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MC68HC908QY4 MC68HC908QT4 MC68HC908QY2 MC68HC908QT2 MC68HC908QY1 MC68HC908QT1
Data Sheet
M68HC08 Microcontrollers
MC68HC908QY4/D Rev. 5 07/2005
freescale.com
MC68HC908QY4 MC68HC908QT4 MC68HC908QY2 MC68HC908QT2 MC68HC908QY1 MC68HC908QT1
Data Sheet
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FreescaleTM and the Freescale logo are trademarks of Freescale Semiconductor, Inc. This product incorporates SuperFlash(R) technology licensed from SST. (c) Freescale Semiconductor, Inc., 2005. All rights reserved. MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 3
Revision History
The following revision history table summarizes changes contained in this document. For your convenience, the page number designators have been linked to the appropriate location.
Revision History (Sheet 1 of 3)
Date September, 2002 Revision Level N/A Initial release 1.2 Features -- Added 8-pin dual flat no lead (DFN) packages to features list. Figure 1-2. MCU Pin Assignments -- Figure updated to include DFN packages. Figure 2-1. Memory Map -- Clarified illegal address and unimplemented memory. Figure 2-2. Control, Status, and Data Registers -- Corrected bit definitions for Port A Data Register (PTA) and Data Direction Register A (DDRA). Table 13-3. Interrupt Sources -- Corrected vector addresses for keyboard interrupt and ADC conversion complete interrupt. Chapter 13 System Integration Module (SIM) -- Removed reference to break status register as it is duplicated in break module. 11.3.1 Internal Oscillator and 11.3.1.1 Internal Oscillator Trimming -- Clarified oscillator trim option ordering information and what to expect with untrimmed device. Figure 11-5. Oscillator Trim Register (OSCTRIM) -- Bit 1 designation corrected. December, 2002 Figure 15-13. Monitor Mode Circuit (Internal Clock, No High Voltage) -- Diagram updated for clarity. 0.1 Figure 12-1. I/O Port Register Summary -- Corrected bit definitions for PTA7, DDRA7, and DDRA6. Figure 12-2. Port A Data Register (PTA) -- Corrected bit definition for PTA7. Figure 12-3. Data Direction Register A (DDRA) -- Corrected bit definitions for DDRA7 and DDRA6. Figure 12-6. Port B Data Register (PTB) -- Corrected bit definition for PTB1 Chapter 9 Keyboard Interrupt Module (KBI) -- Section reworked after deletion of auto wakeup for clarity. Chapter 4 Auto Wakeup Module (AWU) -- New section added for clarity. Figure 10-1. LVI Module Block Diagram -- Corrected LVI stop representation. Chapter 16 Electrical Specifications -- Extensive changes made to electrical specifications. 17.5 8-Pin Dual Flat No Lead (DFN) Package (Case #1452) -- Added case outline drawing for DFN package. Chapter 17 Ordering Information and Mechanical Specifications -- Added ordering information for DFN package. January, 2003 0.2 4.2 Features -- Corrected third bulleted item. Description Page Number(s) N/A 19 21 27 27 118 113
92 98 150 99 100 101 103 83 49 87 169 177 185 49
MC68HC908QY/QT Family Data Sheet, Rev. 5 4 Freescale Semiconductor
Revision History (Sheet 2 of 3)
Date Revision Level Description Reformatted to meet latest M68HC08 documentation standards Figure 1-1. Block Diagram -- Diagram redrawn to include keyboard interrupt module and TCLK pin designator. Figure 1-2. MCU Pin Assignments -- Added TCLK pin designator. Table 1-2. Pin Functions -- Added TCLK pin description. Table 1-3. Function Priority in Shared Pins -- Revised table for clarity and to add TCLK. August, 2003 Figure 2-1. Memory Map -- Corrected names for the IRQ status and control register (INTSCR) bits 3-0. 1.0 3.7.3 ADC Input Clock Register -- Clarified bit description for the ADC clock prescaler bits. 4.3 Functional Description -- Updated periodic wakeup request values. Figure 6-1. COP Block Diagram -- Reworked for clarity Chapter 8 External Interrupt (IRQ) -- Corrected bit names for MODE, IRQF, ACK, and IMASK Chapter 14 Timer Interface Module (TIM) -- Added TCLK function. 15.3 Monitor Module (MON) -- Updated with additional data. Chapter 16 Electrical Specifications -- Updated with additional data. Figure 2-2. Control, Status, and Data Registers -- Deleted unimplemented areas from $FFB0-$FFBD and $FFC2-$FFCF as they are actually available. Also corrected $FFBF designation from unimplemented to reserved. Figure 6-1. COP Block Diagram -- Reworked for clarity 6.3.2 STOP Instruction -- Added subsection 13.4.2 Active Resets from Internal Sources -- Reworked notes for clarity. October, 2003 2.0 Table 13-2. Reset Recovery Timing -- Replaced previous table with new information. Chapter 14 Timer Interface Module (TIM) -- Updated with additional data. Figure 15-3. Break I/O Register Summary -- Corrected bit designators for the BRKAR register 15.3 Monitor Module (MON) -- Clarified seventh bullet. Table 17-1. MC Order Numbers -- Corrected temperature and package designators. Figure 2-2. Control, Status, and Data Registers -- Corrected reset state for the FLASH Block Protect Register at address location $FFBE and the Internal Oscillator Trim Value at $FFC0. Figure 2-5. FLASH Block Protect Register (FLBPR) -- Restated reset state for clarity. Page Number(s) N/A 20 21 22 23 26 47 51 59 77-79 131-139 147 169-173 27 59 60 111 112 131 143 147 175
January, 2004
32
3.0
38
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 5
Revision History
Revision History (Sheet 3 of 3)
Date Revision Level Description Reformatted to meet current documentation standards 6.3.1 BUSCLKX4 -- Clarified description of BUSCLKX4 Chapter 7 Central Processor Unit (CPU) -- In 7.7 Instruction Set Summary: Reworked definitions for STOP instruction Added WAIT instruction November, 2004 4.0 13.8.1 SIM Reset Status Register -- Clarified SRSR flag setting 14.9.1 TIM Status and Control Register -- Added information to TSTOP note 16.8 5-V Oscillator Characteristics -- Added values for deviation from trimmed inernal oscillator 16.12 3-V Oscillator Characteristics -- Added values for deviation from trimmed inernal oscillator Figure 5-2. Configuration Register 1 (CONFIG1) -- Clarified bit definitions for COPRS. July, 2005 Chapter 8 External Interrupt (IRQ) -- Reworked for clarification. 5.0 11.3.4 RC Oscillator -- Improved RC oscillator wording. 12.1 Introduction -- Added note pertaining to non-bonded port pins. 17.3 Package Dimensions -- Updated package information. Page Number(s) Throughout 58 70 71 117 127 155 158 54 73 93 97 165
MC68HC908QY/QT Family Data Sheet, Rev. 5 6 Freescale Semiconductor
List of Chapters
Chapter 1 General Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Chapter 2 Memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 Chapter 3 Analog-to-Digital Converter (ADC). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 Chapter 4 Auto Wakeup Module (AWU) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 Chapter 5 Configuration Register (CONFIG) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 Chapter 6 Computer Operating Properly (COP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 Chapter 7 Central Processor Unit (CPU). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61 Chapter 8 External Interrupt (IRQ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73 Chapter 9 Keyboard Interrupt Module (KBI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79 Chapter 10 Low-Voltage Inhibit (LVI). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85 Chapter 11 Oscillator Module (OSC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89 Chapter 12 Input/Output Ports (PORTS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97 Chapter 13 System Integration Module (SIM) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103 Chapter 14 Timer Interface Module (TIM) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119 Chapter 15 Development Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133 Chapter 16 Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149 Chapter 17 Ordering Information and Mechanical Specifications . . . . . . . . . . . . . . . . . . 165
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 7
List of Chapters
MC68HC908QY/QT Family Data Sheet, Rev. 5 8 Freescale Semiconductor
Table of Contents
Chapter 1 General Description
1.1 1.2 1.3 1.4 1.5 1.6 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . MCU Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Pin Assignments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Pin Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Pin Function Priority. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 17 19 19 22 23
Chapter 2 Memory
2.1 2.2 2.3 2.4 2.5 2.6 2.6.1 2.6.2 2.6.3 2.6.4 2.6.5 2.6.6 2.6.7 2.6.8 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Unimplemented Memory Locations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Reserved Memory Locations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Input/Output (I/O) Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Random-Access Memory (RAM) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . FLASH Memory (FLASH) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . FLASH Control Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . FLASH Page Erase Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . FLASH Mass Erase Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . FLASH Program Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . FLASH Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . FLASH Block Protect Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Stop Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 25 25 27 32 33 33 34 35 35 36 38 39 39
Chapter 3 Analog-to-Digital Converter (ADC)
3.1 3.2 3.3 3.3.1 3.3.2 3.3.3 3.3.4 3.3.5 3.4 3.5 3.5.1 3.5.2 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ADC Port I/O Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Voltage Conversion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Conversion Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Continuous Conversion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Accuracy and Precision . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Low-Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Stop Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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41 41 41 41 44 44 44 44 44 44 44 45
Table of Contents
3.6 3.7 3.7.1 3.7.2 3.7.3
Input/Output Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Input/Output Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ADC Status and Control Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ADC Data Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ADC Input Clock Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
45 45 45 47 47
Chapter 4 Auto Wakeup Module (AWU)
4.1 4.2 4.3 4.4 4.5 4.6 4.6.1 4.6.2 4.6.3 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Stop Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Input/Output Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Port A I/O Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Keyboard Status and Control Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Keyboard Interrupt Enable Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 49 49 50 50 51 51 51 52
Chapter 5 Configuration Register (CONFIG)
5.1 5.2 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
Chapter 6 Computer Operating Properly (COP)
6.1 6.2 6.3 6.3.1 6.3.2 6.3.3 6.3.4 6.3.5 6.3.6 6.3.7 6.4 6.5 6.6 6.7 6.7.1 6.7.2 6.8 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I/O Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . BUSCLKX4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . STOP Instruction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . COPCTL Write . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Power-On Reset. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Internal Reset. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . COPD (COP Disable). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . COPRS (COP Rate Select) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . COP Control Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Monitor Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Low-Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Stop Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . COP Module During Break Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 57 58 58 58 58 58 58 58 59 59 59 59 59 59 59 59
MC68HC908QY/QT Family Data Sheet, Rev. 5 10 Freescale Semiconductor
Chapter 7 Central Processor Unit (CPU)
7.1 7.2 7.3 7.3.1 7.3.2 7.3.3 7.3.4 7.3.5 7.4 7.5 7.5.1 7.5.2 7.6 7.7 7.8 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . CPU Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Accumulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Index Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Stack Pointer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Program Counter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Condition Code Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Arithmetic/Logic Unit (ALU) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Low-Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Stop Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . CPU During Break Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Instruction Set Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Opcode Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61 61 61 62 62 63 63 64 65 65 65 65 65 66 71
Chapter 8 External Interrupt (IRQ)
8.1 8.2 8.3 8.3.1 8.3.2 8.4 8.5 8.5.1 8.5.2 8.6 8.7 8.7.1 8.8 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . MODE = 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . MODE = 0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Low-Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Stop Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IRQ Module During Break Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I/O Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IRQ Input Pins (IRQ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73 73 73 75 75 76 76 76 76 76 76 77 77
Chapter 9 Keyboard Interrupt Module (KBI)
9.1 9.2 9.3 9.3.1 9.3.2 9.4 9.5 9.6 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Keyboard Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Keyboard Initialization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Stop Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Keyboard Module During Break Interrupts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79 79 79 79 82 82 82 82
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9.7 9.7.1 9.7.2
Input/Output Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83 Keyboard Status and Control Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83 Keyboard Interrupt Enable Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
Chapter 10 Low-Voltage Inhibit (LVI)
10.1 10.2 10.3 10.3.1 10.3.2 10.3.3 10.3.4 10.4 10.5 10.6 10.6.1 10.6.2 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Polled LVI Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Forced Reset Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Voltage Hysteresis Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . LVI Trip Selection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . LVI Status Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . LVI Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Low-Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Stop Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85 85 85 86 86 86 86 87 87 87 87 87
Chapter 11 Oscillator Module (OSC)
11.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.2 Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.3 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.3.1 Internal Oscillator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.3.1.1 Internal Oscillator Trimming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.3.1.2 Internal to External Clock Switching . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.3.2 External Oscillator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.3.3 XTAL Oscillator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.3.4 RC Oscillator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.4 Oscillator Module Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.4.1 Crystal Amplifier Input Pin (OSC1). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.4.2 Crystal Amplifier Output Pin (OSC2/PTA4/BUSCLKX4) . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.4.3 Oscillator Enable Signal (SIMOSCEN) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.4.4 XTAL Oscillator Clock (XTALCLK). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.4.5 RC Oscillator Clock (RCCLK) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.4.6 Internal Oscillator Clock (INTCLK) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.4.7 Oscillator Out 2 (BUSCLKX4) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.4.8 Oscillator Out (BUSCLKX2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.5 Low Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.5.1 Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.5.2 Stop Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.6 Oscillator During Break Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.7 CONFIG2 Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.8 Input/Output (I/O) Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.8.1 Oscillator Status Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.8.2 Oscillator Trim Register (OSCTRIM) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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89 89 89 90 91 91 91 92 93 93 93 94 94 94 94 94 94 94 95 95 95 95 95 95 96 96
Chapter 12 Input/Output Ports (PORTS)
12.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97 12.2 Port A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97 12.2.1 Port A Data Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98 12.2.2 Data Direction Register A. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98 12.2.3 Port A Input Pullup Enable Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99 12.3 Port B . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100 12.3.1 Port B Data Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100 12.3.2 Data Direction Register B. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101 12.3.3 Port B Input Pullup Enable Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102
Chapter 13 System Integration Module (SIM)
13.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.2 RST and IRQ Pins Initialization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.3 SIM Bus Clock Control and Generation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.3.1 Bus Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.3.2 Clock Start-Up from POR. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.3.3 Clocks in Stop Mode and Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.4 Reset and System Initialization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.4.1 External Pin Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.4.2 Active Resets from Internal Sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.4.2.1 Power-On Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.4.2.2 Computer Operating Properly (COP) Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.4.2.3 Illegal Opcode Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.4.2.4 Illegal Address Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.4.2.5 Low-Voltage Inhibit (LVI) Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.5 SIM Counter. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.5.1 SIM Counter During Power-On Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.5.2 SIM Counter During Stop Mode Recovery. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.5.3 SIM Counter and Reset States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.6 Exception Control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.6.1 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.6.1.1 Hardware Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.6.1.2 SWI Instruction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.6.2 Interrupt Status Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.6.2.1 Interrupt Status Register 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.6.2.2 Interrupt Status Register 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.6.2.3 Interrupt Status Register 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.6.3 Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.6.4 Break Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.6.5 Status Flag Protection in Break Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.7 Low-Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.7.1 Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.7.2 Stop Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103 104 104 105 105 105 105 106 106 107 108 108 108 108 108 108 109 109 109 109 111 112 112 113 113 113 114 114 114 114 114 115
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13.8 SIM Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116 13.8.1 SIM Reset Status Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117 13.8.2 Break Flag Control Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118
Chapter 14 Timer Interface Module (TIM)
14.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14.2 Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14.3 Pin Name Conventions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14.4 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14.4.1 TIM Counter Prescaler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14.4.2 Input Capture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14.4.3 Output Compare. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14.4.3.1 Unbuffered Output Compare . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14.4.3.2 Buffered Output Compare . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14.4.4 Pulse Width Modulation (PWM) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14.4.4.1 Unbuffered PWM Signal Generation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14.4.4.2 Buffered PWM Signal Generation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14.4.4.3 PWM Initialization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14.5 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14.6 Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14.7 TIM During Break Interrupts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14.8 Input/Output Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14.8.1 TIM Clock Pin (PTA2/TCLK) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14.8.2 TIM Channel I/O Pins (PTA0/TCH0 and PTA1/TCH1). . . . . . . . . . . . . . . . . . . . . . . . . . . . 14.9 Input/Output Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14.9.1 TIM Status and Control Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14.9.2 TIM Counter Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14.9.3 TIM Counter Modulo Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14.9.4 TIM Channel Status and Control Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14.9.5 TIM Channel Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119 119 119 121 122 122 122 122 122 123 124 124 125 125 126 126 126 126 126 126 127 128 129 129 132
Chapter 15 Development Support
15.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15.2 Break Module (BRK) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15.2.1 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15.2.1.1 Flag Protection During Break Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15.2.1.2 TIM During Break Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15.2.1.3 COP During Break Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15.2.2 Break Module Registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15.2.2.1 Break Status and Control Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15.2.2.2 Break Address Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15.2.2.3 Break Auxiliary Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15.2.2.4 Break Status Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15.2.2.5 Break Flag Control Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15.2.3 Low-Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
MC68HC908QY/QT Family Data Sheet, Rev. 5 14 Freescale Semiconductor
133 133 133 135 135 135 135 136 136 137 137 138 138
15.3 Monitor Module (MON) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15.3.1 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15.3.1.1 Normal Monitor Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15.3.1.2 Forced Monitor Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15.3.1.3 Monitor Vectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15.3.1.4 Data Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15.3.1.5 Break Signal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15.3.1.6 Baud Rate. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15.3.1.7 Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15.3.2 Security . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
138 139 142 143 143 144 144 144 144 148
Chapter 16 Electrical Specifications
16.1 16.2 16.3 16.4 16.5 16.6 16.7 16.8 16.9 16.10 16.11 16.12 16.13 16.14 16.15 16.16 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Absolute Maximum Ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Functional Operating Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Thermal Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-V DC Electrical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Typical 5-V Output Drive Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-V Control Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-V Oscillator Characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-V DC Electrical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Typical 3.0-V Output Drive Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-V Control Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-V Oscillator Characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Supply Current Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Analog-to-Digital Converter Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Timer Interface Module Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Memory Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149 149 150 150 151 152 153 154 155 156 157 158 159 161 162 163
Chapter 17 Ordering Information and Mechanical Specifications
17.1 17.2 17.3 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165 MC Order Numbers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165 Package Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 15
Table of Contents
MC68HC908QY/QT Family Data Sheet, Rev. 5 16 Freescale Semiconductor
Chapter 1 General Description
1.1 Introduction
The MC68HC908QY4 is a member of the low-cost, high-performance M68HC08 Family of 8-bit microcontroller units (MCUs). The M68HC08 Family is a Complex Instruction Set Computer (CISC) with a Von Neumann architecture. All MCUs in the family use the enhanced M68HC08 central processor unit (CPU08) and are available with a variety of modules, memory sizes and types, and package types.
0.4
Table 1-1. Summary of Device Variations
Device MC68HC908QT1 MC68HC908QT2 MC68HC908QT4 MC68HC908QY1 MC68HC908QY2 MC68HC908QY4 FLASH Memory Size 1536 bytes 1536 bytes 4096 bytes 1536 bytes 1536 bytes 4096 bytes Analog-to-Digital Converter -- 4 ch, 8 bit 4 ch, 8 bit -- 4 ch, 8 bit 4 ch, 8 bit Pin Count 8 pins 8 pins 8 pins 16 pins 16 pins 16 pins
1.2 Features
Features include: * High-performance M68HC08 CPU core * Fully upward-compatible object code with M68HC05 Family * 5-V and 3-V operating voltages (VDD) * 8-MHz internal bus operation at 5 V, 4-MHz at 3 V * Trimmable internal oscillator - 3.2 MHz internal bus operation - 8-bit trim capability allows 0.4% accuracy(1) - 25% untrimmed * Auto wakeup from STOP capability * Configuration (CONFIG) register for MCU configuration options, including: - Low-voltage inhibit (LVI) trip point * In-system FLASH programming * FLASH security(2)
1. The oscillator frequency is guaranteed to 5% over temperature and voltage range after trimming. 2. No security feature is absolutely secure. However, Freescale's strategy is to make reading or copying the FLASH difficult for unauthorized users. MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 17
General Description
*
* * * *
* * *
* * * * * * *
*
On-chip in-application programmable FLASH memory (with internal program/erase voltage generation) - MC68HC908QY4 and MC68HC908QT4 -- 4096 bytes - MC68HC908QY2, MC68HC908QY1, MC68HC908QT2, and MC68HC908QT1 -- 1536 bytes 128 bytes of on-chip random-access memory (RAM) 2-channel, 16-bit timer interface module (TIM) 4-channel, 8-bit analog-to-digital converter (ADC) on MC68HC908QY2, MC68HC908QY4, MC68HC908QT2, and MC68HC908QT4 5 or 13 bidirectional input/output (I/O) lines and one input only: - Six shared with keyboard interrupt function and ADC - Two shared with timer channels - One shared with external interrupt (IRQ) - Eight extra I/O lines on 16-pin package only - High current sink/source capability on all port pins - Selectable pullups on all ports, selectable on an individual bit basis - Three-state ability on all port pins 6-bit keyboard interrupt with wakeup feature (KBI) Low-voltage inhibit (LVI) module features: - Software selectable trip point in CONFIG register System protection features: - Computer operating properly (COP) watchdog - Low-voltage detection with reset - Illegal opcode detection with reset - Illegal address detection with reset External asynchronous interrupt pin with internal pullup (IRQ) shared with general-purpose input pin Master asynchronous reset pin (RST) shared with general-purpose input/output (I/O) pin Power-on reset Internal pullups on IRQ and RST to reduce external components Memory mapped I/O registers Power saving stop and wait modes MC68HC908QY4, MC68HC908QY2, and MC68HC908QY1 are available in these packages: - 16-pin plastic dual in-line package (PDIP) - 16-pin small outline integrated circuit (SOIC) package - 16-pin thin shrink small outline package (TSSOP) MC68HC908QT4, MC68HC908QT2, and MC68HC908QT1 are available in these packages: - 8-pin PDIP - 8-pin SOIC - 8-pin dual flat no lead (DFN) package
MC68HC908QY/QT Family Data Sheet, Rev. 5 18 Freescale Semiconductor
MCU Block Diagram
Features of the CPU08 include the following: * Enhanced HC05 programming model * Extensive loop control functions * 16 addressing modes (eight more than the HC05) * 16-bit index register and stack pointer * Memory-to-memory data transfers * Fast 8 x 8 multiply instruction * Fast 16/8 divide instruction * Binary-coded decimal (BCD) instructions * Optimization for controller applications * Efficient C language support
1.3 MCU Block Diagram
Figure 1-1 shows the structure of the MC68HC908QY4.
1.4 Pin Assignments
The MC68HC908QT4, MC68HC908QT2, and MC68HC908QT1 are available in 8-pin packages and the MC68HC908QY4, MC68HC908QY2, and MC68HC908QY1 in 16-pin packages. Figure 1-2 shows the pin assignment for these packages.
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 19
General Description
PTA0/AD0/TCH0/KBI0 PTA1/AD1/TCH1/KBI1 DDRA PTA PTA2/IRQ/KBI2/TCLK PTA3/RST/KBI3 PTA4/OSC2/AD2/KBI4 PTA5/OSC1/AD3/KBI5 M68HC08 CPU PTB0 PTB1 PTB2 PTB3 PTB4 PTB5 PTB6 PTB7 CLOCK GENERATOR (OSCILLATOR)
SYSTEM INTEGRATION MODULE SINGLE INTERRUPT MODULE BREAK MODULE POWER-ON RESET MODULE MC68HC908QY4 AND MC68HC908QT4 4096 BYTES MC68HC908QY2, MC68HC908QY1, MC68HC908QT2, AND MC68HC908QT1: 1536 BYTES USER FLASH KEYBOARD INTERRUPT MODULE 16-BIT TIMER MODULE COP MODULE VDD
8-BIT ADC
128 BYTES RAM
POWER SUPPLY VSS
DDRB
PTB
MONITOR ROM
RST, IRQ: Pins have internal (about 30K Ohms) pull up PTA[0:5]: High current sink and source capability PTA[0:5]: Pins have programmable keyboard interrupt and pull up PTB[0:7]: Not available on 8-pin devices - MC68HC908QT1, MC68HC908QT2, and MC68HC908QT4 (see note in 12.1 Introduction) ADC: Not available on the MC68HC908QY1 and MC68HC908QT1
Figure 1-1. Block Diagram
MC68HC908QY/QT Family Data Sheet, Rev. 5 20 Freescale Semiconductor
Pin Assignments
VDD PTA5/OSC1/KBI5 PTA4/OSC2/KBI4 PTA3/RST/KBI3
1 2 3 4
8 7 6 5
VSS PTA0/TCH0/KBI0 PTA1/TCH1/KBI1 PTA2/IRQ/KBI2/TCLK
VDD PTA5/OSC1/AD3/KBI5 PTA4/OSC2/AD2/KBI4 PTA3/RST/KBI3
1 2 3 4
8 7 6 5
VSS PTA0/AD0/TCH0/KBI0 PTA1/AD1/TCH1/KBI1 PTA2/IRQ/KBI2/TCLK
8-PIN ASSIGNMENT MC68HC908QT1 PDIP/SOIC
8-PIN ASSIGNMENT MC68HC908QT2 AND MC68HC908QT4 PDIP/SOIC
VDD PTB7 PTB6 PTA5/OSC1/KBI5 PTA4/OSC2/KBI4 PTB5 PTB4 PTA3/RST/KBI3
1 2 3 4 5 6 7 8
16 15 14 13 12 11 10 9
VSS PTB0 PTB1 PTA0/TCH0/KBI0 PTA1/TCH1/KBI1 PTB2 PTB3 PTA2/IRQ/KBI2/TCLK
VDD PTB7 PTB6 PTA5/OSC1/AD3/KBI5 PTA4/OSC2/AD2/KBI4 PTB5 PTB4 PTA3/RST/KBI3
1 2 3 4 5 6 7 8
16 15 14 13 12 11 10 9
VSS PTB0 PTB1 PTA0/AD0/TCH0/KBI0 PTA1/AD1/TCH1/KBI1 PTB2 PTB3 PTA2/IRQ/KBI2/TCLK
16-PIN ASSIGNMENT MC68HC908QY1 PDIP/SOIC
16-PIN ASSIGNMENT MC68HC908QY2 AND MC68HC908QY4 PDIP/SOIC
PTA0/TCH0/KBI0 PTB1 PTB0 VSS VDD PTB7 PTB6 PTA5/OSC1/KBI5
1 2 3 4 5 6 7 8
16 15 14 13 12 11 10 9
PTA1/TCH1/KBI1 PTB2 PTB3 PTA2/IRQ/KBI2/TCLK PTA3/RST/KBI3 PTB4 PTB5 PTA4/OSC2/KBI4
PTA0/AD0/TCH0/KBI0 PTB1 PTB0 VSS VDD PTB7 PTB6 PTA5/OSC1/AD3/KBI5
1 2 3 4 5 6 7 8
16 15 14 13 12 11 10 9
PTA1/AD1/TCH1/KBI1 PTB2 PTB3 PTA2/IRQ/KBI2/TCLK PTA3/RST/KBI3 PTB4 PTB5 PTA4/OSC2/AD2/KBI4
16-PIN ASSIGNMENT MC68HC908QY1 TSSOP
16-PIN ASSIGNMENT MC68HC908QY2 AND MC68HC908QY4 TSSOP
PTA0/TCH0/KBI0 1 VSS 2 VDD 3 PTA5/OSC1/KB15 4
8 PTA1/TCH1/KBI1 7 PTA2/IRQ/KBI2/TCLK 6 PTA3/RST/KBI3 5 PTA4/OSC2/KBI4
PTA0/AD0/TCH0/KBI0 1 VSS 2 VDD 3 PTA5//OSC1/AD3/KB15 4
8 PTA1/AD1/TCH1/KBI1 7 PTA2/IRQ/KBI2/TCLK 6 PTA3/RST/KBI3 5 PTA4/OSC2/AD2/KBI4
8-PIN ASSIGNMENT MC68HC908QT1 DFN
8-PIN ASSIGNMENT MC68HC908QT2 AND MC68HC908QT4 DFN
Figure 1-2. MCU Pin Assignments
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 21
General Description
1.5 Pin Functions
Table 1-2 provides a description of the pin functions. Table 1-2. Pin Functions
Pin Name VDD VSS Power supply Power supply ground PTA0 -- General purpose I/O port AD0 -- A/D channel 0 input PTA0 TCH0 -- Timer Channel 0 I/O KBI0 -- Keyboard interrupt input 0 PTA1 -- General purpose I/O port AD1 -- A/D channel 1 input PTA1 TCH1 -- Timer Channel 1 I/O KBI1 -- Keyboard interrupt input 1 PTA2 -- General purpose input-only port IRQ -- External interrupt with programmable pullup and Schmitt trigger input PTA2 KBI2 -- Keyboard interrupt input 2 TCLK -- Timer clock input PTA3 -- General purpose I/O port PTA3 RST -- Reset input, active low with internal pullup and Schmitt trigger KBI3 -- Keyboard interrupt input 3 PTA4 -- General purpose I/O port OSC2 --XTAL oscillator output (XTAL option only) RC or internal oscillator output (OSC2EN = 1 in PTAPUE register) AD2 -- A/D channel 2 input KBI4 -- Keyboard interrupt input 4 PTA5 -- General purpose I/O port OSC1 -- XTAL, RC, or external oscillator input PTA5 AD3 -- A/D channel 3 input KBI5 -- Keyboard interrupt input 5 PTB[0:7](1) 8 general-purpose I/O ports Input Input Input/Output Input Input Input/Output Input Input Input/Output Output Output Input Input Input/Output Input Input/Output Input Input Input Input/Output Input Input/Output Input Description Input/Output Power Power Input/Output Input
PTA4
1. The PTB pins are not available on the 8-pin packages (see note in 12.1 Introduction).
MC68HC908QY/QT Family Data Sheet, Rev. 5 22 Freescale Semiconductor
Pin Function Priority
1.6 Pin Function Priority
Table 1-3 is meant to resolve the priority if multiple functions are enabled on a single pin. NOTE Upon reset all pins come up as input ports regardless of the priority table. Table 1-3. Function Priority in Shared Pins
Pin Name PTA0 PTA1 PTA2 PTA3 PTA4 PTA5 Highest-to-Lowest Priority Sequence AD0 TCH0 KBI0 PTA0 AD1 TCH1 KBI1 PTA1 IRQ KBI2 TCLK PTA2 RST KBI3 PTA3 OSC2 AD2 KBI4 PTA4 OSC1 AD3 KBI5 PTA5
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 23
General Description
MC68HC908QY/QT Family Data Sheet, Rev. 5 24 Freescale Semiconductor
Chapter 2 Memory
2.1 Introduction
The central processor unit (CPU08) can address 64 Kbytes of memory space. The memory map, shown in Figure 2-1, includes: * 4096 bytes of user FLASH for MC68HC908QT4 and MC68HC908QY4 * 1536 bytes of user FLASH for MC68HC908QT2, MC68HC908QT1, MC68HC908QY2, and MC68HC908QY1 * 128 bytes of random access memory (RAM) * 48 bytes of user-defined vectors, located in FLASH * 416 bytes of monitor read-only memory (ROM) * 1536 bytes of FLASH program and erase routines, located in ROM
2.2 Unimplemented Memory Locations
Accessing an unimplemented location can have unpredictable effects on MCU operation. In Figure 2-1 and in register figures in this document, unimplemented locations are shaded.
2.3 Reserved Memory Locations
Accessing a reserved location can have unpredictable effects on MCU operation. In Figure 2-1 and in register figures in this document, reserved locations are marked with the word Reserved or with the letter R.
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 25
Memory
$0000 $003F $0040 $007F $0080 $00FF $0100 $27FF $2800 $2DFF $2E00 $EDFF $EE00 $FDFF $FE00 $FE01 $FE02 $FE03 $FE04 $FE05 $FE06 $FE07 $FE08 $FE09 $FE0A $FE0B $FE0C $FE0D $FE0F $FE10 $FFAF $FFB0 $FFBD $FFBE $FFBF $FFC0 $FFC1 $FFC2 $FFCF $FFD0 $FFFF
I/O REGISTERS 64 BYTES RESERVED(1) 64 BYTES RAM 128 BYTES UNIMPLEMENTED(1) 9984 BYTES AUXILIARY ROM 1536 BYTES UNIMPLEMENTED(1) 49152 BYTES FLASH MEMORY MC68HC908QT4 AND MC68HC908QY4 4096 BYTES BREAK STATUS REGISTER (BSR) RESET STATUS REGISTER (SRSR) BREAK AUXILIARY REGISTER (BRKAR) BREAK FLAG CONTROL REGISTER (BFCR) INTERRUPT STATUS REGISTER 1 (INT1) INTERRUPT STATUS REGISTER 2 (INT2) INTERRUPT STATUS REGISTER 3 (INT3) RESERVED FOR FLASH TEST CONTROL REGISTER (FLTCR) FLASH CONTROL REGISTER (FLCR) BREAK ADDRESS HIGH REGISTER (BRKH) BREAK ADDRESS LOW REGISTER (BRKL) BREAK STATUS AND CONTROL REGISTER (BRKSCR) LVISR RESERVED FOR FLASH TEST 3 BYTES MONITOR ROM 416 BYTES FLASH 14 BYTES FLASH BLOCK PROTECT REGISTER (FLBPR) RESERVED FLASH INTERNAL OSCILLATOR TRIM VALUE RESERVED FLASH FLASH 14 BYTES USER VECTORS 48 BYTES $2E00 UNIMPLEMENTED 51712 BYTES $F7FF FLASH MEMORY 1536 BYTES MC68HC908QT1, MC68HC908QT2, MC68HC908QY1, and MC68HC908QY2 Memory Map $F800 $FDFF
Note 1. Attempts to execute code from addresses in this range will generate an illegal address reset.
Figure 2-1. Memory Map
MC68HC908QY/QT Family Data Sheet, Rev. 5 26 Freescale Semiconductor
Input/Output (I/O) Section
2.4 Input/Output (I/O) Section
Addresses $0000-$003F, shown in Figure 2-2, contain most of the control, status, and data registers. Additional I/O registers have these addresses: * $FE00 -- Break status register, BSR * $FE01 -- Reset status register, SRSR * $FE02 -- Break auxiliary register, BRKAR * $FE03 -- Break flag control register, BFCR * $FE04 -- Interrupt status register 1, INT1 * $FE05 -- Interrupt status register 2, INT2 * $FE06 -- Interrupt status register 3, INT3 * $FE07 -- Reserved * $FE08 -- FLASH control register, FLCR * $FE09 -- Break address register high, BRKH * $FE0A -- Break address register low, BRKL * $FE0B -- Break status and control register, BRKSCR * $FE0C -- LVI status register, LVISR * $FE0D -- Reserved * $FFBE -- FLASH block protect register, FLBPR * $FFC0 -- Internal OSC trim value -- Optional * $FFFF -- COP control register, COPCTL
Addr. $0000
Register Name Port A Data Register Read: (PTA) Write: See page 98. Reset: Port B Data Register (PTB) Write: See page 100. Reset: Unimplemented Unimplemented Data Direction Register A Read: (DDRA) Write: See page 98. Reset: Data Direction Register B (DDRB) Write: See page 101. Reset: Read: Read:
Bit 7 R
6 AWUL
5 PTA5
4 PTA4
3 PTA3
2 PTA2
1 PTA1
Bit 0 PTA0
Unaffected by reset PTB7 PTB6 PTB5 PTB4 PTB3 PTB2 PTB1 PTB0
$0001 $0002 $0003
Unaffected by reset
$0004
R 0 DDRB7 0
R 0 DDRB6 0
DDRA5 0 DDRB5 0
DDRA4 0 DDRB4 0 R
DDRA3 0 DDRB3 0 = Reserved
0 0 DDRB2 0
DDRA1 0 DDRB1 0
DDRA0 0 DDRB0 0
$0005
= Unimplemented
U = Unaffected
Figure 2-2. Control, Status, and Data Registers (Sheet 1 of 5)
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 27
Memory Addr. $0006 $000A Register Name Unimplemented Unimplemented Port A Input Pullup Enable Read: OSC2EN Register (PTAPUE) Write: See page 99. Reset: 0 Port B Input Pullup Enable Read: PTBPUE7 Register (PTBPUE) Write: See page 102. Reset: 0 Unimplemented 0 0 PTBPUE6 0 Bit 7 6 5 4 3 2 1 Bit 0
$000B
PTAPUE5 0 PTBPUE5 0
PTAPUE4 0 PTBPUE4 0
PTAPUE3 0 PTBPUE3 0
PTAPUE2 0 PTBPUE2 0
PTAPUE1 0 PTBPUE1 0
PTAPUE0 0 PTBPUE0 0
$000C $000D $0019
$001A
Keyboard Status and Read: Control Register (KBSCR) Write: See page 83. Reset: Keyboard Interrupt Enable Register (KBIER) Write: See page 84. Reset: Unimplemented IRQ Status and Control Read: Register (INTSCR) Write: See page 77. Reset: Configuration Register 2 (CONFIG2)(1) Write: See page 53. Reset: Read: Read:
0 0 0 0
0 0 AWUIE 0
0 0 KBIE5 0
0 0 KBIE4 0
KEYF 0 KBIE3 0
0 ACKK 0 KBIE2 0
IMASKK 0 KBIE1 0
MODEK 0 KBIE0 0
$001B $001C
0 0 IRQPUD 0
0 0 IRQEN 0
0 0 R 0
0 0
IRQF 0
0 ACK 0 R 0
$001D
IMASK 0 R 0
MODE 0 RSTEN 0(2)
$001E
OSCOPT1 OSCOPT0 0 0
1. One-time writable register after each reset. 2. RSTEN reset to 0 by a power-on reset (POR) only. Configuration Register 1 Read: (CONFIG1)(1) Write: See page 54. Reset:
$001F
COPRS 0
LVISTOP 0
LVIRSTD 0
LVIPWRD 0
LVI5OR3 0(2)
SSREC 0
STOP 0
COPD 0
1. One-time writable register after each reset. 2. LVI5OR3 reset to 0 by a power-on reset (POR) only. TIM Status and Control Read: Register (TSC) Write: See page 127. Reset: TIM Counter Register High Read: (TCNTH) Write: See page 128. Reset: TOF 0 0 Bit 15 0 0 TRST 0 Bit 12 0 R 0 Bit 11 0 = Reserved 0
$0020
TOIE 0 Bit 14 0
TSTOP 1 Bit 13 0
PS2 0 Bit 10 0
PS1 0 Bit 9 0
PS0 0 Bit 8 0
$0021
= Unimplemented
U = Unaffected
Figure 2-2. Control, Status, and Data Registers (Sheet 2 of 5)
MC68HC908QY/QT Family Data Sheet, Rev. 5 28 Freescale Semiconductor
Input/Output (I/O) Section Addr. $0022 Register Name TIM Counter Register Low (TCNTL) Write: See page 128. Reset: TIM Counter Modulo Read: Register High (TMODH) Write: See page 129. Reset: TIM Counter Modulo Register Low (TMODL) Write: See page 129. Reset: TIM Channel 0 Status and Read: Control Register (TSC0) Write: See page 130. Reset: TIM Channel 0 Register High (TCH0H) Write: See page 132. Reset: TIM Channel 0 Read: Register Low (TCH0L) Write: See page 132. Reset: TIM Channel 1 Status and Control Register (TSC1) Write: See page 130. Reset: TIM Channel 1 Read: Register High (TCH1H) Write: See page 132. Reset: TIM Channel 1 Register Low (TCH1L) Write: See page 132. Reset: Unimplemented Read: Read: Read: Read: Read: Bit 7 Bit 7 0 Bit 15 1 Bit 7 1 CH0F 0 0 Bit 15 6 Bit 6 0 Bit 14 1 Bit 6 1 CH0IE 0 Bit 14 5 Bit 5 0 Bit 13 1 Bit 5 1 MS0B 0 Bit 13 4 Bit 4 0 Bit 12 1 Bit 4 1 MS0A 0 Bit 12 3 Bit 3 0 Bit 11 1 Bit 3 1 ELS0B 0 Bit 11 2 Bit 2 0 Bit 10 1 Bit 2 1 ELS0A 0 Bit 10 1 Bit 1 0 Bit 9 1 Bit 1 1 TOV0 0 Bit 9 Bit 0 Bit 0 0 Bit 8 1 Bit 0 1 CH0MAX 0 Bit 8
$0023
$0024
$0025
$0026
Indeterminate after reset Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
$0027
Indeterminate after reset CH1F 0 0 Bit 15 CH1IE 0 Bit 14 0 0 Bit 13 MS1A 0 Bit 12 ELS1B 0 Bit 11 ELS1A 0 Bit 10 TOV1 0 Bit 9 CH1MAX 0 Bit 8
$0028
$0029
Indeterminate after reset Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
$002A $002B $0035
Indeterminate after reset
$0036 $0037
Oscillator Status Register Read: (OSCSTAT) Write: See page 96. Reset: Unimplemented Oscillator Trim Register (OSCTRIM) See page 96. Read: Read: Write: Reset:
R 0
R 0
R 0
R 0
R 0
R 0
ECGON 0
ECGST 0
TRIM7 1
TRIM6 0
TRIM5 0
TRIM4 0 R
TRIM3 0 = Reserved
TRIM2 0
TRIM1 0
TRIM0 0
$0038
= Unimplemented
U = Unaffected
Figure 2-2. Control, Status, and Data Registers (Sheet 3 of 5)
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 29
Memory Addr. $0039 $003B Register Name Unimplemented Bit 7 6 5 4 3 2 1 Bit 0
$003C $003D
ADC Status and Control Read: Register (ADSCR) Write: See page 45. Reset: Unimplemented ADC Data Register Read: (ADR) Write: See page 47. Reset: ADC Input Clock Register Read: (ADICLK) Write: See page 47. Reset: Break Status Register (BSR) Write: See page 137. Reset: Read:
COCO R 0
AIEN 0
ADCO 0
CH4 1
CH3 1
CH2 1
CH1 1
CH0 1
$003E
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Indeterminate after reset ADIV2 0 R ADIV1 0 R ADIV0 0 R 0 0 R 0 0 R 0 0 R 0 0 SBSW See note 1 0 1. Writing a 0 clears SBSW. 0 0 R
$003F
$FE00
$FE01
SIM Reset Status Register (SRSR) See page 117.
Read: Write: POR: Read:
POR 1 0 0 BCFE 0 0 R 0 IF14 R 0 0 R 0 R
PIN 0 0 0 R
COP 0 0 0 R
ILOP 0 0 0 R
ILAD 0 0 0 R
MODRST 0 0 0 R
LVI 0 0 0 R
0 0 BDCOP 0 R
$FE02
Break Auxiliary Register (BRKAR) Write: See page 137. Reset: Break Flag Control Read: Register (BFCR) Write: See page 138. Reset: Interrupt Status Register 1 (INT1) Write: See page 77. Reset: Interrupt Status Register 2 Read: (INT2) Write: See page 77. Reset: Interrupt Status Register 3 (INT3) Write: See page 77. Reset: Reserved Read: Read:
$FE03
IF5 R 0 0 R 0 0 R 0 R
IF4 R 0 0 R 0 0 R 0 R
IF3 R 0 0 R 0 0 R 0 R R
0 R 0 0 R 0 0 R 0 R = Reserved
IF1 R 0 0 R 0 0 R 0 R U = Unaffected
0 R 0 0 R 0 0 R 0 R
0 R 0 0 R 0 IF15 R 0 R
$FE04
$FE05
$FE06 $FE07
= Unimplemented
Figure 2-2. Control, Status, and Data Registers (Sheet 4 of 5)
MC68HC908QY/QT Family Data Sheet, Rev. 5 30 Freescale Semiconductor
Input/Output (I/O) Section Addr. $FE08 Register Name FLASH Control Register (FLCR) Write: See page 33. Reset: Break Address High Read: Register (BRKH) Write: See page 136. Reset: Break Address low Register (BRKL) Write: See page 136. Reset: Break Status and Control Read: Register (BRKSCR) Write: See page 136. Reset: LVI Status Register (LVISR) Write: See page 87. Reset: Reserved for FLASH Test Read: Read: Read: Bit 7 0 0 Bit 15 0 Bit 7 0 BRKE 0 LVIOUT 0 R 6 0 0 Bit 14 0 Bit 6 0 BRKA 0 0 0 R 5 0 0 Bit 13 0 Bit 5 0 0 0 0 0 R 4 0 0 Bit 12 0 Bit 4 0 0 0 0 0 R 3 HVEN 0 Bit 11 0 Bit 3 0 0 0 0 0 R 2 MASS 0 Bit 10 0 Bit 2 0 0 0 0 0 R 1 ERASE 0 Bit 9 0 Bit 1 0 0 0 0 0 R Bit 0 PGM 0 Bit 8 0 Bit 0 0 0 0 R 0 R
$FE09
$FE0A
$FE0B
$FE0C $FE0D $FE0F
$FFBE $FFBF
FLASH Block Protect Read: Register (FLBPR) Write: See page 38. Reset: Reserved Read:
BPR7
BPR6
BPR5
BPR4
BPR3
BPR2
BPR1
BPR0
Unaffected by reset R R R R R R R R
$FFC0 $FFC1
Internal Oscillator Trim Value (Optional) Reserved
Write: Reset:
TRIM7
TRIM6
TRIM5
TRIM4
TRIM3
TRIM2
TRIM1
TRIM0
Unaffected by reset R R R R R R R R
$FFFF
COP Control Register Read: (COPCTL) Write: See page 59. Reset:
LOW BYTE OF RESET VECTOR WRITING CLEARS COP COUNTER (ANY VALUE) Unaffected by reset = Unimplemented R = Reserved U = Unaffected
Figure 2-2. Control, Status, and Data Registers (Sheet 5 of 5)
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 31
Memory
Table 2-1. Vector Addresses
Vector Priority Lowest Vector IF15 IF14 IF13 IF6 IF5 IF4 IF3 IF2 IF1 -- -- Address $FFDE $FFDF $FFE0 $FFE1 -- $FFF2 $FFF3 $FFF4 $FFF5 $FFF6 $FFF7 -- $FFFA $FFFB $FFFC $FFFD $FFFE $FFFF Vector ADC conversion complete vector (high) ADC conversion complete vector (low) Keyboard vector (high) Keyboard vector (low) Not used TIM overflow vector (high) TIM overflow vector (low) TIM Channel 1 vector (high) TIM Channel 1 vector (low) TIM Channel 0 vector (high) TIM Channel 0 vector (low) Not used IRQ vector (high) IRQ vector (low) SWI vector (high) SWI vector (low) Reset vector (high) Reset vector (low)
.
Highest
2.5 Random-Access Memory (RAM)
Addresses $0080-$00FF are RAM locations. The location of the stack RAM is programmable. The 16-bit stack pointer allows the stack to be anywhere in the 64-Kbyte memory space. NOTE For correct operation, the stack pointer must point only to RAM locations. Before processing an interrupt, the central processor unit (CPU) uses five bytes of the stack to save the contents of the CPU registers. NOTE For M6805, M146805, and M68HC05 compatibility, the H register is not stacked. During a subroutine call, the CPU uses two bytes of the stack to store the return address. The stack pointer decrements during pushes and increments during pulls. NOTE Be careful when using nested subroutines. The CPU may overwrite data in the RAM during a subroutine or during the interrupt stacking operation.
MC68HC908QY/QT Family Data Sheet, Rev. 5 32 Freescale Semiconductor
FLASH Memory (FLASH)
2.6 FLASH Memory (FLASH)
This subsection describes the operation of the embedded FLASH memory. The FLASH memory can be read, programmed, and erased from a single external supply. The program and erase operations are enabled through the use of an internal charge pump. The FLASH memory consists of an array of 4096 or 1536 bytes with an additional 48 bytes for user vectors. The minimum size of FLASH memory that can be erased is 64 bytes; and the maximum size of FLASH memory that can be programmed in a program cycle is 32 bytes (a row). Program and erase operations are facilitated through control bits in the FLASH control register (FLCR). Details for these operations appear later in this section. The address ranges for the user memory and vectors are: * $EE00 - $FDFF; user memory, 4096 bytes: MC68HC908QY4 and MC68HC908QT4 * $F800 - $FDFF; user memory, 1536 bytes: MC68HC908QY2, MC68HC908QT2, MC68HC908QY1 and MC68HC908QT1 * $FFD0 - $FFFF; user interrupt vectors, 48 bytes. NOTE An erased bit reads as a 1 and a programmed bit reads as a 0. A security feature prevents viewing of the FLASH contents.(1)
2.6.1 FLASH Control Register
The FLASH control register (FLCR) controls FLASH program and erase operations.
Address: Read: Write: Reset: 0 0 = Unimplemented 0 0 $FE08 Bit 7 0 6 0 5 0 4 0 3 HVEN 0 2 MASS 0 1 ERASE 0 Bit 0 PGM 0
Figure 2-3. FLASH Control Register (FLCR) HVEN -- High Voltage Enable Bit This read/write bit enables high voltage from the charge pump to the memory for either program or erase operation. It can only be set if either PGM =1 or ERASE =1 and the proper sequence for program or erase is followed. 1 = High voltage enabled to array and charge pump on 0 = High voltage disabled to array and charge pump off MASS -- Mass Erase Control Bit This read/write bit configures the memory for mass erase operation. 1 = Mass erase operation selected 0 = Mass erase operation unselected
1. No security feature is absolutely secure. However, Freescale's strategy is to make reading or copying the FLASH difficult for unauthorized users. MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 33
Memory
ERASE -- Erase Control Bit This read/write bit configures the memory for erase operation. ERASE is interlocked with the PGM bit such that both bits cannot be equal to 1 or set to 1 at the same time. 1 = Erase operation selected 0 = Erase operation unselected PGM -- Program Control Bit This read/write bit configures the memory for program operation. PGM is interlocked with the ERASE bit such that both bits cannot be equal to 1 or set to 1 at the same time. 1 = Program operation selected 0 = Program operation unselected
2.6.2 FLASH Page Erase Operation
Use the following procedure to erase a page of FLASH memory. A page consists of 64 consecutive bytes starting from addresses $XX00, $XX40, $XX80, or $XXC0. The 48-byte user interrupt vectors area also forms a page. Any FLASH memory page can be erased alone. 1. Set the ERASE bit and clear the MASS bit in the FLASH control register. 2. Read the FLASH block protect register. 3. Write any data to any FLASH location within the address range of the block to be erased. 4. Wait for a time, tNVS (minimum 10 s). 5. Set the HVEN bit. 6. Wait for a time, tErase (minimum 1 ms or 4 ms). 7. Clear the ERASE bit. 8. Wait for a time, tNVH (minimum 5 s). 9. Clear the HVEN bit. 10. After time, tRCV (typical 1 s), the memory can be accessed in read mode again. NOTE Programming and erasing of FLASH locations cannot be performed by code being executed from the FLASH memory. While these operations must be performed in the order as shown, but other unrelated operations may occur between the steps. CAUTION A page erase of the vector page will erase the internal oscillator trim value at $FFC0. In applications that require more than 1000 program/erase cycles, use the 4 ms page erase specification to get improved long-term reliability. Any application can use this 4 ms page erase specification. However, in applications where a FLASH location will be erased and reprogrammed less than 1000 times, and speed is important, use the 1 ms page erase specification to get a shorter cycle time.
MC68HC908QY/QT Family Data Sheet, Rev. 5 34 Freescale Semiconductor
FLASH Memory (FLASH)
2.6.3 FLASH Mass Erase Operation
Use the following procedure to erase the entire FLASH memory to read as a 1: 1. Set both the ERASE bit and the MASS bit in the FLASH control register. 2. Read the FLASH block protect register. 3. Write any data to any FLASH address(1) within the FLASH memory address range. 4. Wait for a time, tNVS (minimum 10 s). 5. Set the HVEN bit. 6. Wait for a time, tMErase (minimum 4 ms). 7. Clear the ERASE and MASS bits. NOTE Mass erase is disabled whenever any block is protected (FLBPR does not equal $FF). 8. Wait for a time, tNVHL (minimum 100 s). 9. Clear the HVEN bit. 10. After time, tRCV (typical 1 s), the memory can be accessed in read mode again. NOTE Programming and erasing of FLASH locations cannot be performed by code being executed from the FLASH memory. While these operations must be performed in the order as shown, but other unrelated operations may occur between the steps. CAUTION A mass erase will erase the internal oscillator trim value at $FFC0.
2.6.4 FLASH Program Operation
Programming of the FLASH memory is done on a row basis. A row consists of 32 consecutive bytes starting from addresses $XX00, $XX20, $XX40, $XX60, $XX80, $XXA0, $XXC0, or $XXE0. Use the following step-by-step procedure to program a row of FLASH memory Figure 2-4 shows a flowchart of the programming algorithm. NOTE Only bytes which are currently $FF may be programmed. 1. Set the PGM bit. This configures the memory for program operation and enables the latching of address and data for programming. 2. Read the FLASH block protect register. 3. Write any data to any FLASH location within the address range desired. 4. Wait for a time, tNVS (minimum 10 s). 5. Set the HVEN bit. 6. Wait for a time, tPGS (minimum 5 s). 7. Write data to the FLASH address being programmed(2).
1. When in monitor mode, with security sequence failed (see 15.3.2 Security), write to the FLASH block protect register instead of any FLASH address. 2. The time between each FLASH address change, or the time between the last FLASH address programmed to clearing PGM bit, must not exceed the maximum programming time, tPROG maximum. MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 35
Memory
8. 9. 10. 11. 12. 13.
Wait for time, tPROG (minimum 30 s). Repeat step 7 and 8 until all desired bytes within the row are programmed. Clear the PGM bit(1). Wait for time, tNVH (minimum 5 s). Clear the HVEN bit. After time, tRCV (typical 1 s), the memory can be accessed in read mode again. NOTE The COP register at location $FFFF should not be written between steps 5-12, when the HVEN bit is set. Since this register is located at a valid FLASH address, unpredictable behavior may occur if this location is written while HVEN is set.
This program sequence is repeated throughout the memory until all data is programmed. NOTE Programming and erasing of FLASH locations cannot be performed by code being executed from the FLASH memory. While these operations must be performed in the order shown, other unrelated operations may occur between the steps. Do not exceed tPROG maximum, see 16.16 Memory Characteristics.
2.6.5 FLASH Protection
Due to the ability of the on-board charge pump to erase and program the FLASH memory in the target application, provision is made to protect blocks of memory from unintentional erase or program operations due to system malfunction. This protection is done by use of a FLASH block protect register (FLBPR). The FLBPR determines the range of the FLASH memory which is to be protected. The range of the protected area starts from a location defined by FLBPR and ends to the bottom of the FLASH memory ($FFFF). When the memory is protected, the HVEN bit cannot be set in either ERASE or PROGRAM operations. NOTE In performing a program or erase operation, the FLASH block protect register must be read after setting the PGM or ERASE bit and before asserting the HVEN bit. When the FLBPR is programmed with all 0 s, the entire memory is protected from being programmed and erased. When all the bits are erased (all 1's), the entire memory is accessible for program and erase. When bits within the FLBPR are programmed, they lock a block of memory. The address ranges are shown in 2.6.6 FLASH Block Protect Register. Once the FLBPR is programmed with a value other than $FF, any erase or program of the FLBPR or the protected block of FLASH memory is prohibited. Mass erase is disabled whenever any block is protected (FLBPR does not equal $FF). The FLBPR itself can be erased or programmed only with an external voltage, VTST, present on the IRQ pin. This voltage also allows entry from reset into the monitor mode.
MC68HC908QY/QT Family Data Sheet, Rev. 5 36 Freescale Semiconductor
FLASH Memory (FLASH)
Algorithm for Programming a Row (32 Bytes) of FLASH Memory
1
SET PGM BIT
2 READ THE FLASH BLOCK PROTECT REGISTER
3
WRITE ANY DATA TO ANY FLASH ADDRESS WITHIN THE ROW ADDRESS RANGE DESIRED
4
WAIT FOR A TIME, tNVS
5
SET HVEN BIT
6
WAIT FOR A TIME, tPGS
7
WRITE DATA TO THE FLASH ADDRESS TO BE PROGRAMMED
8
WAIT FOR A TIME, tPROG
9
COMPLETED PROGRAMMING THIS ROW? N 10
Y
CLEAR PGM BIT
11
WAIT FOR A TIME, tNVH
NOTES: The time between each FLASH address change (step 7 to step 7), or the time between the last FLASH address programmed to clearing PGM bit (step 7 to step 10) must not exceed the maximum programming time, tPROG max. This row program algorithm assumes the row/s to be programmed are initially erased.
12
CLEAR HVEN BIT
13
WAIT FOR A TIME, tRCV
END OF PROGRAMMING
Figure 2-4. FLASH Programming Flowchart
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 37
Memory
2.6.6 FLASH Block Protect Register
The FLASH block protect register is implemented as a byte within the FLASH memory, and therefore can only be written during a programming sequence of the FLASH memory. The value in this register determines the starting address of the protected range within the FLASH memory.
Address: Read: Write: Reset: $FFBE Bit 7 BPR7 6 BPR6 5 BPR5 4 BPR4 3 BPR3 2 BPR2 1 BPR1 Bit 0 BPR0
Unaffected by reset. Initial value from factory is 1.
Write to this register is by a programming sequence to the FLASH memory.
Figure 2-5. FLASH Block Protect Register (FLBPR) BPR[7:0] -- FLASH Protection Register Bits [7:0] These eight bits in FLBPR represent bits [13:6] of a 16-bit memory address. Bits [15:14] are 1s and bits [5:0] are 0s. The resultant 16-bit address is used for specifying the start address of the FLASH memory for block protection. The FLASH is protected from this start address to the end of FLASH memory, at $FFFF. With this mechanism, the protect start address can be XX00, XX40, XX80, or XXC0 within the FLASH memory. See Figure 2-6 and Table 2-2.
16-BIT MEMORY ADDRESS START ADDRESS OF FLASH BLOCK PROTECT 1 1 FLBPR VALUE 0 0 0 0 0 0
Figure 2-6. FLASH Block Protect Start Address Table 2-2. Examples of Protect Start Address
BPR[7:0] $00-$B8 $B9 (1011 1001) $BA (1011 1010) $BB (1011 1011) $BC (1011 1100) Start of Address of Protect Range The entire FLASH memory is protected. $EE40 (1110 1110 0100 0000) $EE80 (1110 1110 1000 0000) $EEC0 (1110 1110 1100 0000) $EF00 (1110 1111 0000 0000) and so on... $DE (1101 1110) $DF (1101 1111) $FE (1111 1110) $FF $F780 (1111 0111 1000 0000) $F7C0 (1111 0111 1100 0000) $FF80 (1111 1111 1000 0000) FLBPR, OSCTRIM, and vectors are protected The entire FLASH memory is not protected.
MC68HC908QY/QT Family Data Sheet, Rev. 5 38 Freescale Semiconductor
FLASH Memory (FLASH)
2.6.7 Wait Mode
Putting the MCU into wait mode while the FLASH is in read mode does not affect the operation of the FLASH memory directly, but there will not be any memory activity since the CPU is inactive. The WAIT instruction should not be executed while performing a program or erase operation on the FLASH, or the operation will discontinue and the FLASH will be on standby mode.
2.6.8 Stop Mode
Putting the MCU into stop mode while the FLASH is in read mode does not affect the operation of the FLASH memory directly, but there will not be any memory activity since the CPU is inactive. The STOP instruction should not be executed while performing a program or erase operation on the FLASH, or the operation will discontinue and the FLASH will be on standby mode NOTE Standby mode is the power-saving mode of the FLASH module in which all internal control signals to the FLASH are inactive and the current consumption of the FLASH is at a minimum.
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 39
Memory
MC68HC908QY/QT Family Data Sheet, Rev. 5 40 Freescale Semiconductor
Chapter 3 Analog-to-Digital Converter (ADC)
3.1 Introduction
This section describes the analog-to-digital converter (ADC). The ADC is an 8-bit, 4-channel analog-todigital converter. The ADC module is only available on the MC68HC908QY2, MC68HC908QT2, MC68HC908QY4, and MC68HC908QT4.
3.2 Features
Features of the ADC module include: * 4 channels with multiplexed input * Linear successive approximation with monotonicity * 8-bit resolution * Single or continuous conversion * Conversion complete flag or conversion complete interrupt * Selectable ADC clock frequency
3.3 Functional Description
Four ADC channels are available for sampling external sources at pins PTA0, PTA1, PTA4, and PTA5. An analog multiplexer allows the single ADC converter to select one of the four ADC channels as an ADC voltage input (ADCVIN). ADCVIN is converted by the successive approximation register-based counters. The ADC resolution is eight bits. When the conversion is completed, ADC puts the result in the ADC data register and sets a flag or generates an interrupt. Figure 3-2 shows a block diagram of the ADC.
3.3.1 ADC Port I/O Pins
PTA0, PTA1, PTA4, and PTA5 are general-purpose I/O pins that are shared with the ADC channels. The channel select bits (ADC status and control register (ADSCR), $003C), define which ADC channel/port pin will be used as the input signal. The ADC overrides the port I/O logic by forcing that pin as input to the ADC. The remaining ADC channels/port pins are controlled by the port I/O logic and can be used as general-purpose I/O. Writes to the port register or data direction register (DDR) will not have any affect on the port pin that is selected by the ADC. Read of a port pin which is in use by the ADC will return a 0 if the corresponding DDR bit is at 0. If the DDR bit is at 1, the value in the port data latch is read.
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 41
Analog-to-Digital Converter (ADC)
PTA0/AD0/TCH0/KBI0 PTA1/AD1/TCH1/KBI1 DDRA PTA PTA2/IRQ/KBI2/TCLK PTA3/RST/KBI3 PTA4/OSC2/AD2/KBI4 PTA5/OSC1/AD3/KBI5 M68HC08 CPU PTB0 PTB1 PTB2 PTB3 PTB4 PTB5 PTB6 PTB7 CLOCK GENERATOR (OSCILLATOR)
SYSTEM INTEGRATION MODULE SINGLE INTERRUPT MODULE BREAK MODULE POWER-ON RESET MODULE MC68HC908QY4 AND MC68HC908QT4 4096 BYTES MC68HC908QY2, MC68HC908QY1, MC68HC908QT2, AND MC68HC908QT1: 1536 BYTES USER FLASH KEYBOARD INTERRUPT MODULE 16-BIT TIMER MODULE COP MODULE VDD
8-BIT ADC
128 BYTES RAM
POWER SUPPLY VSS
DDRB
PTB
MONITOR ROM
RST, IRQ: Pins have internal (about 30K Ohms) pull up PTA[0:5]: High current sink and source capability PTA[0:5]: Pins have programmable keyboard interrupt and pull up PTB[0:7]: Not available on 8-pin devices - MC68HC908QT1, MC68HC908QT2, and MC68HC908QT4 (see note in 12.1 Introduction) ADC: Not available on the MC68HC908QY1 and MC68HC908QT1
Figure 3-1. Block Diagram Highlighting ADC Block and Pins
MC68HC908QY/QT Family Data Sheet, Rev. 5 42 Freescale Semiconductor
Functional Description
INTERNAL DATA BUS READ DDRA DISABLE RESET WRITE PTA PTAx ADCx DDRAx
WRITE DDRA
READ PTA
DISABLE ADC CHANNEL x ADC DATA REGISTER
INTERRUPT LOGIC
CONVERSION COMPLETE
ADC VOLTAGE IN ADCVIN ADC
CHANNEL SELECT (1 OF 4 CHANNELS)
CH[4:0]
AIEN
COCO
ADC CLOCK
BUS CLOCK
CLOCK GENERATOR
ADIV[2:0]
Figure 3-2. ADC Block Diagram
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 43
Analog-to-Digital Converter (ADC)
3.3.2 Voltage Conversion
When the input voltage to the ADC equals VDD, the ADC converts the signal to $FF (full scale). If the input voltage equals VSS, the ADC converts it to $00. Input voltages between VDD and VSS are a straight-line linear conversion. All other input voltages will result in $FF if greater than VDD and $00 if less than VSS. NOTE Input voltage should not exceed the analog supply voltages.
3.3.3 Conversion Time
Sixteen ADC internal clocks are required to perform one conversion. The ADC starts a conversion on the first rising edge of the ADC internal clock immediately following a write to the ADSCR. If the ADC internal clock is selected to run at 1 MHz, then one conversion will take 16 s to complete. With a 1-MHz ADC internal clock the maximum sample rate is 62.5 kHz.
Conversion Time = 16 ADC Clock Cycles ADC Clock Frequency Number of Bus Cycles = Conversion Time x Bus Frequency
3.3.4 Continuous Conversion
In the continuous conversion mode (ADCO = 1), the ADC continuously converts the selected channel filling the ADC data register (ADR) with new data after each conversion. Data from the previous conversion will be overwritten whether that data has been read or not. Conversions will continue until the ADCO bit is cleared. The COCO bit (ADSCR, $003C) is set after each conversion and will stay set until the next read of the ADC data register. When a conversion is in process and the ADSCR is written, the current conversion data should be discarded to prevent an incorrect reading.
3.3.5 Accuracy and Precision
The conversion process is monotonic and has no missing codes.
3.4 Interrupts
When the AIEN bit is set, the ADC module is capable of generating a central processor unit (CPU) interrupt after each ADC conversion. A CPU interrupt is generated if the COCO bit is at 0. The COCO bit is not used as a conversion complete flag when interrupts are enabled.
3.5 Low-Power Modes
The following subsections describe the ADC in low-power modes.
3.5.1 Wait Mode
The ADC continues normal operation during wait mode. Any enabled CPU interrupt request from the ADC can bring the microcontroller unit (MCU) out of wait mode. If the ADC is not required to bring the MCU out of wait mode, power down the ADC by setting the CH[4:0] bits in ADSCR to 1s before executing the WAIT instruction.
MC68HC908QY/QT Family Data Sheet, Rev. 5 44 Freescale Semiconductor
Input/Output Signals
3.5.2 Stop Mode
The ADC module is inactive after the execution of a STOP instruction. Any pending conversion is aborted. ADC conversions resume when the MCU exits stop mode. Allow one conversion cycle to stabilize the analog circuitry before using ADC data after exiting stop mode.
3.6 Input/Output Signals
The ADC module has four channels that are shared with I/O port A. ADC voltage in (ADCVIN) is the input voltage signal from one of the four ADC channels to the ADC module.
3.7 Input/Output Registers
These I/O registers control and monitor ADC operation: * ADC status and control register (ADSCR) * ADC data register (ADR) * ADC clock register (ADICLK)
3.7.1 ADC Status and Control Register
The following paragraphs describe the function of the ADC status and control register (ADSCR). When a conversion is in process and the ADSCR is written, the current conversion data should be discarded to prevent an incorrect reading.
Address: $003C Bit 7 Read: Write: Reset: COCO R 0 R 6 AIEN 0 = Reserved 5 ADCO 0 4 CH4 1 3 CH3 1 2 CH2 1 1 CH1 1 Bit 0 CH0 1
Figure 3-3. ADC Status and Control Register (ADSCR) COCO -- Conversions Complete Bit In non-interrupt mode (AIEN = 0), COCO is a read-only bit that is set at the end of each conversion. COCO will stay set until cleared by a read of the ADC data register. Reset clears this bit. In interrupt mode (AIEN = 1), COCO is a read-only bit that is not set at the end of a conversion. It always reads as a 0. 1 = Conversion completed (AIEN = 0) 0 = Conversion not completed (AIEN = 0) or CPU interrupt enabled (AIEN = 1) NOTE The write function of the COCO bit is reserved. When writing to the ADSCR register, always have a 0 in the COCO bit position.
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 45
Analog-to-Digital Converter (ADC)
AIEN -- ADC Interrupt Enable Bit When this bit is set, an interrupt is generated at the end of an ADC conversion. The interrupt signal is cleared when ADR is read or ADSCR is written. Reset clears the AIEN bit. 1 = ADC interrupt enabled 0 = ADC interrupt disabled ADCO -- ADC Continuous Conversion Bit When set, the ADC will convert samples continuously and update ADR at the end of each conversion. Only one conversion is allowed when this bit is cleared. Reset clears the ADCO bit. 1 = Continuous ADC conversion 0 = One ADC conversion CH[4:0] -- ADC Channel Select Bits CH4, CH3, CH2, CH1, and CH0 form a 5-bit field which is used to select one of the four ADC channels. The five select bits are detailed in Table 3-1. Care should be taken when using a port pin as both an analog and a digital input simultaneously to prevent switching noise from corrupting the analog signal. The ADC subsystem is turned off when the channel select bits are all set to 1. This feature allows for reduced power consumption for the MCU when the ADC is not used. Reset sets all of these bits to 1. NOTE Recovery from the disabled state requires one conversion cycle to stabilize. Table 3-1. MUX Channel Select
CH4 0 0 0 0 0 1 1 1 1 1 1 CH3 0 0 0 0 0 1 1 1 1 1 1 CH2 0 0 0 0 1 0 0 1 1 1 1 CH1 0 0 1 1 0 1 1 0 0 1 1 CH0 0 1 0 1 0 0 1 0 1 0 1 ADC Channel ADC0 ADC1 ADC2 ADC3 -- -- -- -- -- -- -- -- Reserved Unused VDDA(2) VSSA(2) ADC power off Unused(1) Input Select PTA0 PTA1 PTA4 PTA5
1. If any unused channels are selected, the resulting ADC conversion will be unknown. 2. The voltage levels supplied from internal reference nodes, as specified in the table, are used to verify the operation of the ADC converter both in production test and for user applications.
MC68HC908QY/QT Family Data Sheet, Rev. 5 46 Freescale Semiconductor
Input/Output Registers
3.7.2 ADC Data Register
One 8-bit result register is provided. This register is updated each time an ADC conversion completes.
Address: $003E Bit 7 Read: Write: Reset: = Unimplemented Indeterminate after reset AD7 6 AD6 5 AD5 4 AD4 3 AD3 2 AD2 1 AD1 Bit 0 AD0
Figure 3-4. ADC Data Register (ADR)
3.7.3 ADC Input Clock Register
This register selects the clock frequency for the ADC.
Address: $003F Bit 7 Read: Write: Reset: ADIV2 0 6 ADIV1 0 5 ADIV0 0 4 0 0 3 0 0 2 0 0 1 0 0 Bit 0 0 0
= Unimplemented
Figure 3-5. ADC Input Clock Register (ADICLK) ADIV2-ADIV0 -- ADC Clock Prescaler Bits ADIV2, ADIV1, and ADIV0 form a 3-bit field which selects the divide ratio used by the ADC to generate the internal ADC clock. Table 3-2 shows the available clock configurations. The ADC clock frequency should be set between fADIC(MIN) and fADIC(MAX). The analog input level should remain stable for the entire conversion time (maximum = 17 ADC clock cycles). Table 3-2. ADC Clock Divide Ratio
ADIV2 0 0 0 0 1 X = don't care ADIV1 0 0 1 1 X ADIV0 0 1 0 1 X ADC Clock Rate Bus clock / 1 Bus clock / 2 Bus clock / 4 Bus clock / 8 Bus clock / 16
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 47
Analog-to-Digital Converter (ADC)
MC68HC908QY/QT Family Data Sheet, Rev. 5 48 Freescale Semiconductor
Chapter 4 Auto Wakeup Module (AWU)
4.1 Introduction
This section describes the auto wakeup module (AWU). The AWU generates a periodic interrupt during stop mode to wake the part up without requiring an external signal. Figure 4-1 is a block diagram of the AWU.
4.2 Features
Features of the auto wakeup module include: * One internal interrupt with separate interrupt enable bit, sharing the same keyboard interrupt vector and keyboard interrupt mask bit * Exit from low-power stop mode without external signals * Selectable timeout periods * Dedicated low-power internal oscillator separate from the main system clock sources
4.3 Functional Description
The function of the auto wakeup logic is to generate periodic wakeup requests to bring the microcontroller unit (MCU) out of stop mode. The wakeup requests are treated as regular keyboard interrupt requests, with the difference that instead of a pin, the interrupt signal is generated by an internal logic. Writing the AWUIE bit in the keyboard interrupt enable register enables or disables the auto wakeup interrupt input (see Figure 4-1). A logic 1 applied to the AWUIREQ input with auto wakeup interrupt request enabled, latches an auto wakeup interrupt request. Auto wakeup latch, AWUL, can be read directly from the bit 6 position of port A data register (PTA). This is a read-only bit which is occupying an empty bit position on PTA. No PTA associated registers, such as PTA6 data direction or PTA6 pullup exist for this bit. Entering stop mode will enable the auto wakeup generation logic. An internal RC oscillator (exclusive for the auto wakeup feature) drives the wakeup request generator. Once the overflow count is reached in the generator counter, a wakeup request, AWUIREQ, is latched and sent to the KBI logic. See Figure 4-1. Wakeup interrupt requests will only be serviced if the associated interrupt enable bit, AWUIE, in KBIER is set. The AWU shares the keyboard interrupt vector. The overflow count can be selected from two options defined by the COPRS bit in CONFIG1. This bit was "borrowed" from the computer operating properly (COP) using the fact that the COP feature is idle (no MCU clock available) in stop mode. The typical values of the periodic wakeup request are (at room temperature): * COPRS = 0: 650 ms @ 5 V, 875 ms @ 3 V * COPRS = 1: 16 ms @ 5 V, 22 ms @ 3 V
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 49
Auto Wakeup Module (AWU)
COPRS (FROM CONFIG1) AUTOWUGEN 1 = DIV 29 SHORT 0 = DIV 214 INT RC OSC EN 32 kHz CLK OVERFLOW RST VDD TO PTA READ, BIT 6 D Q AWUL
E
AWUIREQ R TO KBI INTERRUPT LOGIC (SEE Figure 9-2. Keyboard Interrupt Block Diagram)
CLRLOGIC CLEAR (CGMXCLK) BUSCLKX4 CLK RST RESET ISTOP RESET ACKK
RESET AWUIE
Figure 4-1. Auto Wakeup Interrupt Request Generation Logic The auto wakeup RC oscillator is highly dependent on operating voltage and temperature. This feature is not recommended for use as a time-keeping function. The wakeup request is latched to allow the interrupt source identification. The latched value, AWUL, can be read directly from the bit 6 position of PTA data register. This is a read-only bit which is occupying an empty bit position on PTA. No PTA associated registers, such as PTA6 data, PTA6 direction, and PTA6 pullup exist for this bit. The latch can be cleared by writing to the ACKK bit in the KBSCR register. Reset also clears the latch. AWUIE bit in KBI interrupt enable register (see Figure 4-1) has no effect on AWUL reading. The AWU oscillator and counters are inactive in normal operating mode and become active only upon entering stop mode.
4.4 Wait Mode
The AWU module remains inactive in wait mode.
4.5 Stop Mode
When the AWU module is enabled (AWUIE = 1 in the keyboard interrupt enable register) it is activated automatically upon entering stop mode. Clearing the IMASKK bit in the keyboard status and control register enables keyboard interrupt requests to bring the MCU out of stop mode. The AWU counters start from `0' each time stop mode is entered.
MC68HC908QY/QT Family Data Sheet, Rev. 5 50 Freescale Semiconductor
Input/Output Registers
4.6 Input/Output Registers
The AWU shares registers with the keyboard interrupt (KBI) module and the port A I/O module. The following I/O registers control and monitor operation of the AWU: * Port A data register (PTA) * Keyboard interrupt status and control register (KBSCR) * Keyboard interrupt enable register (KBIER)
4.6.1 Port A I/O Register
The port A data register (PTA) contains a data latch for the state of the AWU interrupt request, in addition to the data latches for port A.
Address: $0000 Bit 7 Read: Write: Reset: 0 0 = Unimplemented 0 6 AWUL 5 PTA5 4 PTA4 3 PTA3 2 PTA2 1 PTA1 Bit 0 PTA0
Unaffected by reset
Figure 4-2. Port A Data Register (PTA) AWUL -- Auto Wakeup Latch This is a read-only bit which has the value of the auto wakeup interrupt request latch. The wakeup request signal is generated internally. There is no PTA6 port or any of the associated bits such as PTA6 data direction or pullup bits. 1 = Auto wakeup interrupt request is pending 0 = Auto wakeup interrupt request is not pending NOTE PTA5-PTA0 bits are not used in conjuction with the auto wakeup feature. To see a description of these bits, see 12.2.1 Port A Data Register.
4.6.2 Keyboard Status and Control Register
The keyboard status and control register (KBSCR): * Flags keyboard/auto wakeup interrupt requests * Acknowledges keyboard/auto wakeup interrupt requests * Masks keyboard/auto wakeup interrupt requests
Address: $001A Bit 7 Read: Write: Reset: 0 0 0 0 0 = Unimplemented 0 6 0 5 0 4 0 3 KEYF 2 0 ACKK 0 1 IMASKK 0 Bit 0 MODEK 0
Figure 4-3. Keyboard Status and Control Register (KBSCR)
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 51
Auto Wakeup Module (AWU)
Bits 7-4 -- Not used These read-only bits always read as 0s. KEYF -- Keyboard Flag Bit This read-only bit is set when a keyboard interrupt is pending on port A or auto wakeup. Reset clears the KEYF bit. 1 = Keyboard/auto wakeup interrupt pending 0 = No keyboard/auto wakeup interrupt pending ACKK -- Keyboard Acknowledge Bit Writing a 1 to this write-only bit clears the keyboard/auto wakeup interrupt request on port A and auto wakeup logic. ACKK always reads as 0.Reset clears ACKK. IMASKK-- Keyboard Interrupt Mask Bit Writing a 1 to this read/write bit prevents the output of the keyboard interrupt mask from generating interrupt requests on port A or auto wakeup. Reset clears the IMASKK bit. 1 = Keyboard/auto wakeup interrupt requests masked 0 = Keyboard/auto wakeup interrupt requests not masked NOTE MODEK is not used in conjuction with the auto wakeup feature. To see a description of this bit, see 9.7.1 Keyboard Status and Control Register.
4.6.3 Keyboard Interrupt Enable Register
The keyboard interrupt enable register (KBIER) enables or disables the auto wakeup to operate as a keyboard/auto wakeup interrupt input.
Address: $001B Bit 7 Read: Write: Reset: 0 0 6 AWUIE 0 5 KBIE5 0 4 KBIE4 0 3 KBIE3 0 2 KBIE2 0 1 KBIE1 0 Bit 0 KBIE0 0
= Unimplemented
Figure 4-4. Keyboard Interrupt Enable Register (KBIER) AWUIE -- Auto Wakeup Interrupt Enable Bit This read/write bit enables the auto wakeup interrupt input to latch interrupt requests. Reset clears AWUIE. 1 = Auto wakeup enabled as interrupt input 0 = Auto wakeup not enabled as interrupt input NOTE KBIE5-KBIE0 bits are not used in conjuction with the auto wakeup feature. To see a description of these bits, see 9.7.2 Keyboard Interrupt Enable Register.
MC68HC908QY/QT Family Data Sheet, Rev. 5 52 Freescale Semiconductor
Chapter 5 Configuration Register (CONFIG)
5.1 Introduction
This section describes the configuration registers (CONFIG1 and CONFIG2). The configuration registers enable or disable the following options: * Stop mode recovery time (32 x BUSCLKX4 cycles or 4096 x BUSCLKX4 cycles) * STOP instruction * Computer operating properly module (COP) * COP reset period (COPRS): 8176 x BUSCLKX4 or 262,128 x BUSCLKX4 * Low-voltage inhibit (LVI) enable and trip voltage selection * OSC option selection * IRQ pin * RST pin * Auto wakeup timeout period
5.2 Functional Description
The configuration registers are used in the initialization of various options. The configuration registers can be written once after each reset. Most of the configuration register bits are cleared during reset. Since the various options affect the operation of the microcontroller unit (MCU) it is recommended that this register be written immediately after reset. The configuration registers are located at $001E and $001F, and may be read at anytime. NOTE The CONFIG registers are one-time writable by the user after each reset. Upon a reset, the CONFIG registers default to predetermined settings as shown in Figure 5-1 and Figure 5-2.
Address: $001E Bit 7 Read: Write: Reset: POR: IRQPUD 0 0 R 6 IRQEN 0 0 = Reserved 5 R 0 0 4 OSCOPT1 0 0 U = Unaffected 3 OSCOPT0 0 0 2 R 0 0 1 R 0 0 Bit 0 RSTEN U 0
Figure 5-1. Configuration Register 2 (CONFIG2)
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 53
Configuration Register (CONFIG)
IRQPUD -- IRQ Pin Pullup Control Bit 1 = Internal pullup is disconnected 0 = Internal pullup is connected between IRQ pin and VDD IRQEN -- IRQ Pin Function Selection Bit 1 = Interrupt request function active in pin 0 = Interrupt request function inactive in pin OSCOPT1 and OSCOPT0 -- Selection Bits for Oscillator Option (0, 0) Internal oscillator (0, 1) External oscillator (1, 0) External RC oscillator (1, 1) External XTAL oscillator RSTEN -- RST Pin Function Selection 1 = Reset function active in pin 0 = Reset function inactive in pin NOTE The RSTEN bit is cleared by a power-on reset (POR) only. Other resets will leave this bit unaffected.
Address: $001F Bit 7 Read: Write: Reset: POR: COPRS 0 0 U = Unaffected 6 LVISTOP 0 0 5 LVIRSTD 0 0 4 LVIPWRD 0 0 3 LVI5OR3 U 0 2 SSREC 0 0 1 STOP 0 0 Bit 0 COPD 0 0
Figure 5-2. Configuration Register 1 (CONFIG1) COPRS (Out of STOP Mode) -- COP Reset Period Selection Bit 1 = COP reset short cycle = 8176 x BUSCLKX4 0 = COP reset long cycle = 262,128 x BUSCLKX4 COPRS (In STOP Mode) -- Auto Wakeup Period Selection Bit 1 = Auto wakeup short cycle = 512 x INTRCOSC 0 = Auto wakeup long cycle = 16,384 x INTRCOSC LVISTOP -- LVI Enable in Stop Mode Bit When the LVIPWRD bit is clear, setting the LVISTOP bit enables the LVI to operate during stop mode. Reset clears LVISTOP. 1 = LVI enabled during stop mode 0 = LVI disabled during stop mode LVIRSTD -- LVI Reset Disable Bit LVIRSTD disables the reset signal from the LVI module. 1 = LVI module resets disabled 0 = LVI module resets enabled
MC68HC908QY/QT Family Data Sheet, Rev. 5 54 Freescale Semiconductor
Functional Description
LVIPWRD -- LVI Power Disable Bit LVIPWRD disables the LVI module. 1 = LVI module power disabled 0 = LVI module power enabled LVI5OR3 -- LVI 5-V or 3-V Operating Mode Bit LVI5OR3 selects the voltage operating mode of the LVI module. The voltage mode selected for the LVI should match the operating VDD for the LVI's voltage trip points for each of the modes. 1 = LVI operates in 5-V mode 0 = LVI operates in 3-V mode NOTE The LVI5OR3 bit is cleared by a power-on reset (POR) only. Other resets will leave this bit unaffected. SSREC -- Short Stop Recovery Bit SSREC enables the CPU to exit stop mode with a delay of 32 BUSCLKX4 cycles instead of a 4096 BUSCLKX4 cycle delay. 1 = Stop mode recovery after 32 BUSCLKX4 cycles 0 = Stop mode recovery after 4096 BUSCLKX4 cycles NOTE Exiting stop mode by an LVI reset will result in the long stop recovery. The system stabilization time for power-on reset and long stop recovery (both 4096 BUSCLKX4 cycles) gives a delay longer than the LVI enable time for these startup scenarios. There is no period where the MCU is not protected from a low-power condition. However, when using the short stop recovery configuration option, the 32 BUSCLKX4 delay must be greater than the LVI's turn on time to avoid a period in startup where the LVI is not protecting the MCU. STOP -- STOP Instruction Enable Bit STOP enables the STOP instruction. 1 = STOP instruction enabled 0 = STOP instruction treated as illegal opcode COPD -- COP Disable Bit COPD disables the COP module. 1 = COP module disabled 0 = COP module enabled
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 55
Configuration Register (CONFIG)
MC68HC908QY/QT Family Data Sheet, Rev. 5 56 Freescale Semiconductor
Chapter 6 Computer Operating Properly (COP)
6.1 Introduction
The computer operating properly (COP) module contains a free-running counter that generates a reset if allowed to overflow. The COP module helps software recover from runaway code. Prevent a COP reset by clearing the COP counter periodically. The COP module can be disabled through the COPD bit in the configuration 1 (CONFIG1) register.
6.2 Functional Description
BUSCLKX4
12-BIT SIM COUNTER CLEAR ALL STAGES CLEAR STAGES 5-12
RESET CIRCUIT RESET STATUS REGISTER
STOP INSTRUCTION INTERNAL RESET SOURCES COPCTL WRITE
COP CLOCK
COPEN (FROM SIM) COP DISABLE (COPD FROM CONFIG1) RESET COPCTL WRITE COP RATE SELECT (COPRS FROM CONFIG1)
6-BIT COP COUNTER
CLEAR COP COUNTER
Figure 6-1. COP Block Diagram
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 57
COP TIMEOUT
Computer Operating Properly (COP)
The COP counter is a free-running 6-bit counter preceded by the 12-bit system integration module (SIM) counter. If not cleared by software, the COP counter overflows and generates an asynchronous reset after 262,128 or 8176 BUSCLKX4 cycles; depending on the state of the COP rate select bit, COPRS, in configuration register 1. With a 262,128 BUSCLKX4 cycle overflow option, the internal 12.8-MHz oscillator gives a COP timeout period of 20.48 ms. Writing any value to location $FFFF before an overflow occurs prevents a COP reset by clearing the COP counter and stages 12-5 of the SIM counter. NOTE Service the COP immediately after reset and before entering or after exiting stop mode to guarantee the maximum time before the first COP counter overflow. A COP reset pulls the RST pin low (if the RSTEN bit is set in the CONFIG1 register) for 32 x BUSCLKX4 cycles and sets the COP bit in the reset status register (RSR). See 13.8.1 SIM Reset Status Register. NOTE Place COP clearing instructions in the main program and not in an interrupt subroutine. Such an interrupt subroutine could keep the COP from generating a reset even while the main program is not working properly.
6.3 I/O Signals
The following paragraphs describe the signals shown in Figure 6-1.
6.3.1 BUSCLKX4
BUSCLKX4 is the oscillator output signal. BUSCLKX4 frequency is equal to the internal oscillator frequency, the crystal frequency, or the RC-oscillator frequency.
6.3.2 STOP Instruction
The STOP instruction clears the SIM counter.
6.3.3 COPCTL Write
Writing any value to the COP control register (COPCTL) (see 6.4 COP Control Register) clears the COP counter and clears stages 12-5 of the SIM counter. Reading the COP control register returns the low byte of the reset vector.
6.3.4 Power-On Reset
The power-on reset (POR) circuit in the SIM clears the SIM counter 4096 x BUSCLKX4 cycles after power up.
6.3.5 Internal Reset
An internal reset clears the SIM counter and the COP counter.
6.3.6 COPD (COP Disable)
The COPD signal reflects the state of the COP disable bit (COPD) in the configuration register 1 (CONFIG1). See Chapter 5 Configuration Register (CONFIG).
MC68HC908QY/QT Family Data Sheet, Rev. 5 58 Freescale Semiconductor
COP Control Register
6.3.7 COPRS (COP Rate Select)
The COPRS signal reflects the state of the COP rate select bit (COPRS) in the configuration register 1 (CONFIG1). See Chapter 5 Configuration Register (CONFIG).
6.4 COP Control Register
The COP control register (COPCTL) is located at address $FFFF and overlaps the reset vector. Writing any value to $FFFF clears the COP counter and starts a new timeout period. Reading location $FFFF returns the low byte of the reset vector.
Address: $FFFF Bit 7 Read: Write: Reset: 6 5 4 3 2 1 Bit 0 LOW BYTE OF RESET VECTOR CLEAR COP COUNTER Unaffected by reset
Figure 6-2. COP Control Register (COPCTL)
6.5 Interrupts
The COP does not generate CPU interrupt requests.
6.6 Monitor Mode
The COP is disabled in monitor mode when VTST is present on the IRQ pin.
6.7 Low-Power Modes
The WAIT and STOP instructions put the MCU in low power-consumption standby modes.
6.7.1 Wait Mode
The COP continues to operate during wait mode. To prevent a COP reset during wait mode, periodically clear the COP counter.
6.7.2 Stop Mode
Stop mode turns off the BUSCLKX4 input to the COP and clears the SIM counter. Service the COP immediately before entering or after exiting stop mode to ensure a full COP timeout period after entering or exiting stop mode.
6.8 COP Module During Break Mode
The COP is disabled during a break interrupt with monitor mode when BDCOP bit is set in break auxiliary register (BRKAR).
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 59
Computer Operating Properly (COP)
MC68HC908QY/QT Family Data Sheet, Rev. 5 60 Freescale Semiconductor
Chapter 7 Central Processor Unit (CPU)
7.1 Introduction
The M68HC08 CPU (central processor unit) is an enhanced and fully object-code-compatible version of the M68HC05 CPU. The CPU08 Reference Manual (document order number CPU08RM/AD) contains a description of the CPU instruction set, addressing modes, and architecture.
7.2 Features
Features of the CPU include: * Object code fully upward-compatible with M68HC05 Family * 16-bit stack pointer with stack manipulation instructions * 16-bit index register with x-register manipulation instructions * 8-MHz CPU internal bus frequency * 64-Kbyte program/data memory space * 16 addressing modes * Memory-to-memory data moves without using accumulator * Fast 8-bit by 8-bit multiply and 16-bit by 8-bit divide instructions * Enhanced binary-coded decimal (BCD) data handling * Modular architecture with expandable internal bus definition for extension of addressing range beyond 64 Kbytes * Low-power stop and wait modes
7.3 CPU Registers
Figure 7-1 shows the five CPU registers. CPU registers are not part of the memory map.
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 61
Central Processor Unit (CPU)
7 15 H 15 15 X 0 STACK POINTER (SP) 0 PROGRAM COUNTER (PC) 7 0 V11HINZC CONDITION CODE REGISTER (CCR) 0 ACCUMULATOR (A) 0 INDEX REGISTER (H:X)
CARRY/BORROW FLAG ZERO FLAG NEGATIVE FLAG INTERRUPT MASK HALF-CARRY FLAG TWO'S COMPLEMENT OVERFLOW FLAG
Figure 7-1. CPU Registers
7.3.1 Accumulator
The accumulator is a general-purpose 8-bit register. The CPU uses the accumulator to hold operands and the results of arithmetic/logic operations.
Bit 7 Read: Write: Reset: Unaffected by reset 6 5 4 3 2 1 Bit 0
Figure 7-2. Accumulator (A)
7.3.2 Index Register
The 16-bit index register allows indexed addressing of a 64-Kbyte memory space. H is the upper byte of the index register, and X is the lower byte. H:X is the concatenated 16-bit index register. In the indexed addressing modes, the CPU uses the contents of the index register to determine the conditional address of the operand. The index register can serve also as a temporary data storage location.
Bit 15 Read: Write: Reset: 0 0 0 0 0 0 0 0 X X X X X X X X X = Indeterminate 14 13 12 11 10 9 8 7 6 5 4 3 2 1 Bit 0
Figure 7-3. Index Register (H:X)
MC68HC908QY/QT Family Data Sheet, Rev. 5 62 Freescale Semiconductor
CPU Registers
7.3.3 Stack Pointer
The stack pointer is a 16-bit register that contains the address of the next location on the stack. During a reset, the stack pointer is preset to $00FF. The reset stack pointer (RSP) instruction sets the least significant byte to $FF and does not affect the most significant byte. The stack pointer decrements as data is pushed onto the stack and increments as data is pulled from the stack. In the stack pointer 8-bit offset and 16-bit offset addressing modes, the stack pointer can function as an index register to access data on the stack. The CPU uses the contents of the stack pointer to determine the conditional address of the operand.
Bit 15 Read: Write: Reset: 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 14 13 12 11 10 9 8 7 6 5 4 3 2 1 Bit 0
Figure 7-4. Stack Pointer (SP) NOTE The location of the stack is arbitrary and may be relocated anywhere in random-access memory (RAM). Moving the SP out of page 0 ($0000 to $00FF) frees direct address (page 0) space. For correct operation, the stack pointer must point only to RAM locations.
7.3.4 Program Counter
The program counter is a 16-bit register that contains the address of the next instruction or operand to be fetched. Normally, the program counter automatically increments to the next sequential memory location every time an instruction or operand is fetched. Jump, branch, and interrupt operations load the program counter with an address other than that of the next sequential location. During reset, the program counter is loaded with the reset vector address located at $FFFE and $FFFF. The vector address is the address of the first instruction to be executed after exiting the reset state.
Bit 15 Read: Write: Reset: Loaded with vector from $FFFE and $FFFF 14 13 12 11 10 9 8 7 6 5 4 3 2 1 Bit 0
Figure 7-5. Program Counter (PC)
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 63
Central Processor Unit (CPU)
7.3.5 Condition Code Register
The 8-bit condition code register contains the interrupt mask and five flags that indicate the results of the instruction just executed. Bits 6 and 5 are set permanently to 1. The following paragraphs describe the functions of the condition code register.
Bit 7 Read: Write: Reset: V X X = Indeterminate 6 1 1 5 1 1 4 H X 3 I 1 2 N X 1 Z X Bit 0 C X
Figure 7-6. Condition Code Register (CCR) V -- Overflow Flag The CPU sets the overflow flag when a two's complement overflow occurs. The signed branch instructions BGT, BGE, BLE, and BLT use the overflow flag. 1 = Overflow 0 = No overflow H -- Half-Carry Flag The CPU sets the half-carry flag when a carry occurs between accumulator bits 3 and 4 during an add-without-carry (ADD) or add-with-carry (ADC) operation. The half-carry flag is required for binary-coded decimal (BCD) arithmetic operations. The DAA instruction uses the states of the H and C flags to determine the appropriate correction factor. 1 = Carry between bits 3 and 4 0 = No carry between bits 3 and 4 I -- Interrupt Mask When the interrupt mask is set, all maskable CPU interrupts are disabled. CPU interrupts are enabled when the interrupt mask is cleared. When a CPU interrupt occurs, the interrupt mask is set automatically after the CPU registers are saved on the stack, but before the interrupt vector is fetched. 1 = Interrupts disabled 0 = Interrupts enabled NOTE To maintain M6805 Family compatibility, the upper byte of the index register (H) is not stacked automatically. If the interrupt service routine modifies H, then the user must stack and unstack H using the PSHH and PULH instructions. After the I bit is cleared, the highest-priority interrupt request is serviced first. A return-from-interrupt (RTI) instruction pulls the CPU registers from the stack and restores the interrupt mask from the stack. After any reset, the interrupt mask is set and can be cleared only by the clear interrupt mask software instruction (CLI). N -- Negative Flag The CPU sets the negative flag when an arithmetic operation, logic operation, or data manipulation produces a negative result, setting bit 7 of the result. 1 = Negative result 0 = Non-negative result
MC68HC908QY/QT Family Data Sheet, Rev. 5 64 Freescale Semiconductor
Arithmetic/Logic Unit (ALU)
Z -- Zero Flag The CPU sets the zero flag when an arithmetic operation, logic operation, or data manipulation produces a result of $00. 1 = Zero result 0 = Non-zero result C -- Carry/Borrow Flag The CPU sets the carry/borrow flag when an addition operation produces a carry out of bit 7 of the accumulator or when a subtraction operation requires a borrow. Some instructions -- such as bit test and branch, shift, and rotate -- also clear or set the carry/borrow flag. 1 = Carry out of bit 7 0 = No carry out of bit 7
7.4 Arithmetic/Logic Unit (ALU)
The ALU performs the arithmetic and logic operations defined by the instruction set. Refer to the CPU08 Reference Manual (document order number CPU08RM/AD) for a description of the instructions and addressing modes and more detail about the architecture of the CPU.
7.5 Low-Power Modes
The WAIT and STOP instructions put the MCU in low power-consumption standby modes.
7.5.1 Wait Mode
The WAIT instruction: * Clears the interrupt mask (I bit) in the condition code register, enabling interrupts. After exit from wait mode by interrupt, the I bit remains clear. After exit by reset, the I bit is set. * Disables the CPU clock
7.5.2 Stop Mode
The STOP instruction: * Clears the interrupt mask (I bit) in the condition code register, enabling external interrupts. After exit from stop mode by external interrupt, the I bit remains clear. After exit by reset, the I bit is set. * Disables the CPU clock After exiting stop mode, the CPU clock begins running after the oscillator stabilization delay.
7.6 CPU During Break Interrupts
If a break module is present on the MCU, the CPU starts a break interrupt by: * Loading the instruction register with the SWI instruction * Loading the program counter with $FFFC:$FFFD or with $FEFC:$FEFD in monitor mode The break interrupt begins after completion of the CPU instruction in progress. If the break address register match occurs on the last cycle of a CPU instruction, the break interrupt begins immediately. A return-from-interrupt instruction (RTI) in the break routine ends the break interrupt and returns the MCU to normal operation if the break interrupt has been deasserted.
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 65
Central Processor Unit (CPU)
7.7 Instruction Set Summary
Table 7-1 provides a summary of the M68HC08 instruction set. Table 7-1. Instruction Set Summary (Sheet 1 of 6)
Address Mode Opcode Source Form
ADC #opr ADC opr ADC opr ADC opr,X ADC opr,X ADC ,X ADC opr,SP ADC opr,SP ADD #opr ADD opr ADD opr ADD opr,X ADD opr,X ADD ,X ADD opr,SP ADD opr,SP AIS #opr AIX #opr AND #opr AND opr AND opr AND opr,X AND opr,X AND ,X AND opr,SP AND opr,SP ASL opr ASLA ASLX ASL opr,X ASL ,X ASL opr,SP ASR opr ASRA ASRX ASR opr,X ASR opr,X ASR opr,SP BCC rel
Operation
Description
VH I NZC
Add with Carry
A (A) + (M) + (C)
-
IMM DIR EXT IX2 IX1 IX SP1 SP2 IMM DIR EXT IX2 IX1 IX SP1 SP2
A9 B9 C9 D9 E9 F9 9EE9 9ED9 AB BB CB DB EB FB 9EEB 9EDB A7 AF A4 B4 C4 D4 E4 F4 9EE4 9ED4
ii dd hh ll ee ff ff ff ee ff ii dd hh ll ee ff ff ff ee ff ii ii ii dd hh ll ee ff ff ff ee ff
Add without Carry
A (A) + (M)
-
Add Immediate Value (Signed) to SP Add Immediate Value (Signed) to H:X
SP (SP) + (16 M) H:X (H:X) + (16 M)
- - - - - - IMM - - - - - - IMM IMM DIR EXT IX2 - IX1 IX SP1 SP2 DIR INH INH IX1 IX SP1 DIR INH INH IX1 IX SP1
Logical AND
A (A) & (M)
0--
Arithmetic Shift Left (Same as LSL)
C b7 b0
0
--
38 dd 48 58 68 ff 78 9E68 ff 37 dd 47 57 67 ff 77 9E67 ff 24 11 13 15 17 19 1B 1D 1F 25 27 90 92 28 29 22 rr dd dd dd dd dd dd dd dd rr rr rr rr rr rr rr
Arithmetic Shift Right
b7 b0
C
--
Branch if Carry Bit Clear
PC (PC) + 2 + rel ? (C) = 0
- - - - - - REL DIR (b0) DIR (b1) DIR (b2) - - - - - - DIR (b3) DIR (b4) DIR (b5) DIR (b6) DIR (b7) - - - - - - REL - - - - - - REL - - - - - - REL
BCLR n, opr
Clear Bit n in M
Mn 0
BCS rel BEQ rel BGE opr BGT opr BHCC rel BHCS rel BHI rel
Branch if Carry Bit Set (Same as BLO) Branch if Equal Branch if Greater Than or Equal To (Signed Operands) Branch if Greater Than (Signed Operands) Branch if Half Carry Bit Clear Branch if Half Carry Bit Set Branch if Higher
PC (PC) + 2 + rel ? (C) = 1 PC (PC) + 2 + rel ? (Z) = 1 PC (PC) + 2 + rel ? (N V) = 0
PC (PC) + 2 + rel ? (Z) | (N V) = 0 - - - - - - REL PC (PC) + 2 + rel ? (H) = 0 PC (PC) + 2 + rel ? (H) = 1 PC (PC) + 2 + rel ? (C) | (Z) = 0 - - - - - - REL - - - - - - REL - - - - - - REL
3 3
MC68HC908QY/QT Family Data Sheet, Rev. 5 66 Freescale Semiconductor
Cycles
2 3 4 4 3 2 4 5 2 3 4 4 3 2 4 5 2 2 2 3 4 4 3 2 4 5 4 1 1 4 3 5 4 1 1 4 3 5 3 4 4 4 4 4 4 4 4 3 3 3 3 3
Effect on CCR
Operand
Instruction Set Summary
Table 7-1. Instruction Set Summary (Sheet 2 of 6)
Address Mode Opcode Source Form
BHS rel BIH rel BIL rel BIT #opr BIT opr BIT opr BIT opr,X BIT opr,X BIT ,X BIT opr,SP BIT opr,SP BLE opr BLO rel BLS rel BLT opr BMC rel BMI rel BMS rel BNE rel BPL rel BRA rel
Operation
Branch if Higher or Same (Same as BCC) Branch if IRQ Pin High Branch if IRQ Pin Low
Description
PC (PC) + 2 + rel ? (C) = 0 PC (PC) + 2 + rel ? IRQ = 1 PC (PC) + 2 + rel ? IRQ = 0
VH I NZC
- - - - - - REL - - - - - - REL - - - - - - REL IMM DIR EXT - IX2 IX1 IX SP1 SP2
24 2F 2E A5 B5 C5 D5 E5 F5 9EE5 9ED5 93 25 23 91 2C 2B 2D 26 2A 20 01 03 05 07 09 0B 0D 0F 21 00 02 04 06 08 0A 0C 0E 10 12 14 16 18 1A 1C 1E AD 31 41 51 61 71 9E61 98 9A
rr rr rr ii dd hh ll ee ff ff ff ee ff rr rr rr rr rr rr rr rr rr rr dd rr dd rr dd rr dd rr dd rr dd rr dd rr dd rr rr dd rr dd rr dd rr dd rr dd rr dd rr dd rr dd rr dd dd dd dd dd dd dd dd rr dd rr ii rr ii rr ff rr rr ff rr
Bit Test
(A) & (M)
0--
Branch if Less Than or Equal To (Signed Operands) Branch if Lower (Same as BCS) Branch if Lower or Same Branch if Less Than (Signed Operands) Branch if Interrupt Mask Clear Branch if Minus Branch if Interrupt Mask Set Branch if Not Equal Branch if Plus Branch Always
PC (PC) + 2 + rel ? (Z) | (N V) = 1 - - - - - - REL PC (PC) + 2 + rel ? (C) = 1 PC (PC) + 2 + rel ? (C) | (Z) = 1 PC (PC) + 2 + rel ? (N V) =1 PC (PC) + 2 + rel ? (I) = 0 PC (PC) + 2 + rel ? (N) = 1 PC (PC) + 2 + rel ? (I) = 1 PC (PC) + 2 + rel ? (Z) = 0 PC (PC) + 2 + rel ? (N) = 0 PC (PC) + 2 + rel - - - - - - REL - - - - - - REL - - - - - - REL - - - - - - REL - - - - - - REL - - - - - - REL - - - - - - REL - - - - - - REL - - - - - - REL DIR (b0) DIR (b1) DIR (b2) DIR (b3) DIR (b4) DIR (b5) DIR (b6) DIR (b7) DIR (b0) DIR (b1) DIR (b2) DIR (b3) DIR (b4) DIR (b5) DIR (b6) DIR (b7)
BRCLR n,opr,rel Branch if Bit n in M Clear
PC (PC) + 3 + rel ? (Mn) = 0
-----
BRN rel
Branch Never
PC (PC) + 2
- - - - - - REL
BRSET n,opr,rel Branch if Bit n in M Set
PC (PC) + 3 + rel ? (Mn) = 1
-----
BSET n,opr
Set Bit n in M
Mn 1
DIR (b0) DIR (b1) DIR (b2) - - - - - - DIR (b3) DIR (b4) DIR (b5) DIR (b6) DIR (b7) - - - - - - REL DIR IMM - - - - - - IMM IX1+ IX+ SP1 - - - - - 0 INH - - 0 - - - INH
BSR rel
Branch to Subroutine
PC (PC) + 2; push (PCL) SP (SP) - 1; push (PCH) SP (SP) - 1 PC (PC) + rel PC (PC) + 3 + rel ? (A) - (M) = $00 PC (PC) + 3 + rel ? (A) - (M) = $00 PC (PC) + 3 + rel ? (X) - (M) = $00 PC (PC) + 3 + rel ? (A) - (M) = $00 PC (PC) + 2 + rel ? (A) - (M) = $00 PC (PC) + 4 + rel ? (A) - (M) = $00 C0 I0
CBEQ opr,rel CBEQA #opr,rel CBEQX #opr,rel Compare and Branch if Equal CBEQ opr,X+,rel CBEQ X+,rel CBEQ opr,SP,rel CLC CLI Clear Carry Bit Clear Interrupt Mask
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 67
Cycles
3 3 3 2 3 4 4 3 2 4 5 3 3 3 3 3 3 3 3 3 3 5 5 5 5 5 5 5 5 3 5 5 5 5 5 5 5 5 4 4 4 4 4 4 4 4 4 5 4 4 5 4 6 1 2
Effect on CCR
Operand
Central Processor Unit (CPU)
Table 7-1. Instruction Set Summary (Sheet 3 of 6)
Address Mode Opcode Source Form
CLR opr CLRA CLRX CLRH CLR opr,X CLR ,X CLR opr,SP CMP #opr CMP opr CMP opr CMP opr,X CMP opr,X CMP ,X CMP opr,SP CMP opr,SP COM opr COMA COMX COM opr,X COM ,X COM opr,SP CPHX #opr CPHX opr CPX #opr CPX opr CPX opr CPX ,X CPX opr,X CPX opr,X CPX opr,SP CPX opr,SP DAA
Operation
Description
M $00 A $00 X $00 H $00 M $00 M $00 M $00
VH I NZC
Clear
DIR INH INH 0 - - 0 1 - INH IX1 IX SP1 IMM DIR EXT IX2 IX1 IX SP1 SP2 DIR INH INH 1 IX1 IX SP1 IMM DIR IMM DIR EXT IX2 IX1 IX SP1 SP2 INH
3F dd 4F 5F 8C 6F ff 7F 9E6F ff A1 B1 C1 D1 E1 F1 9EE1 9ED1 ii dd hh ll ee ff ff ff ee ff
Compare A with M
(A) - (M)
--
Complement (One's Complement)
M (M) = $FF - (M) A (A) = $FF - (M) X (X) = $FF - (M) M (M) = $FF - (M) M (M) = $FF - (M) M (M) = $FF - (M) (H:X) - (M:M + 1)
0--
33 dd 43 53 63 ff 73 9E63 ff 65 75 A3 B3 C3 D3 E3 F3 9EE3 9ED3 72 3B 4B 5B 6B 7B 9E6B dd rr rr rr ff rr rr ff rr ii ii+1 dd ii dd hh ll ee ff ff ff ee ff
Compare H:X with M
--
Compare X with M
(X) - (M)
--
Decimal Adjust A
(A)10
U--
DBNZ opr,rel DBNZA rel DBNZX rel Decrement and Branch if Not Zero DBNZ opr,X,rel DBNZ X,rel DBNZ opr,SP,rel DEC opr DECA DECX DEC opr,X DEC ,X DEC opr,SP DIV EOR #opr EOR opr EOR opr EOR opr,X EOR opr,X EOR ,X EOR opr,SP EOR opr,SP INC opr INCA INCX INC opr,X INC ,X INC opr,SP
A (A) - 1 or M (M) - 1 or X (X) - 1 PC (PC) + 3 + rel ? (result) 0 DIR PC (PC) + 2 + rel ? (result) 0 INH PC (PC) + 2 + rel ? (result) 0 - - - - - - INH PC (PC) + 3 + rel ? (result) 0 IX1 PC (PC) + 2 + rel ? (result) 0 IX PC (PC) + 4 + rel ? (result) 0 SP1 M (M) - 1 A (A) - 1 X (X) - 1 M (M) - 1 M (M) - 1 M (M) - 1 A (H:A)/(X) H Remainder DIR INH INH - IX1 IX SP1 INH IMM DIR EXT - IX2 IX1 IX SP1 SP2 DIR INH - INH IX1 IX SP1
Decrement
--
3A dd 4A 5A 6A ff 7A 9E6A ff 52 A8 B8 C8 D8 E8 F8 9EE8 9ED8 ii dd hh ll ee ff ff ff ee ff
Divide
----
Exclusive OR M with A
A (A M)
0--
Increment
M (M) + 1 A (A) + 1 X (X) + 1 M (M) + 1 M (M) + 1 M (M) + 1
--
3C dd 4C 5C 6C ff 7C 9E6C ff
MC68HC908QY/QT Family Data Sheet, Rev. 5 68 Freescale Semiconductor
Cycles
3 1 1 1 3 2 4 2 3 4 4 3 2 4 5 4 1 1 4 3 5 3 4 2 3 4 4 3 2 4 5 2 5 3 3 5 4 6 4 1 1 4 3 5 7 2 3 4 4 3 2 4 5 4 1 1 4 3 5
Effect on CCR
Operand
Instruction Set Summary
Table 7-1. Instruction Set Summary (Sheet 4 of 6)
Address Mode Opcode Source Form
JMP opr JMP opr JMP opr,X JMP opr,X JMP ,X JSR opr JSR opr JSR opr,X JSR opr,X JSR ,X LDA #opr LDA opr LDA opr LDA opr,X LDA opr,X LDA ,X LDA opr,SP LDA opr,SP LDHX #opr LDHX opr LDX #opr LDX opr LDX opr LDX opr,X LDX opr,X LDX ,X LDX opr,SP LDX opr,SP LSL opr LSLA LSLX LSL opr,X LSL ,X LSL opr,SP LSR opr LSRA LSRX LSR opr,X LSR ,X LSR opr,SP MOV opr,opr MOV opr,X+ MOV #opr,opr MOV X+,opr MUL NEG opr NEGA NEGX NEG opr,X NEG ,X NEG opr,SP NOP NSA ORA #opr ORA opr ORA opr ORA opr,X ORA opr,X ORA ,X ORA opr,SP ORA opr,SP PSHA PSHH PSHX
Operation
Description
VH I NZC
PC Jump Address
Jump
DIR EXT - - - - - - IX2 IX1 IX DIR EXT - - - - - - IX2 IX1 IX IMM DIR EXT IX2 - IX1 IX SP1 SP2 - IMM DIR
BC CC DC EC FC BD CD DD ED FD A6 B6 C6 D6 E6 F6 9EE6 9ED6 45 55 AE BE CE DE EE FE 9EEE 9EDE
dd hh ll ee ff ff dd hh ll ee ff ff ii dd hh ll ee ff ff ff ee ff ii jj dd ii dd hh ll ee ff ff ff ee ff
Jump to Subroutine
PC (PC) + n (n = 1, 2, or 3) Push (PCL); SP (SP) - 1 Push (PCH); SP (SP) - 1 PC Unconditional Address
Load A from M
A (M)
0--
Load H:X from M
H:X (M:M + 1)
0--
Load X from M
X (M)
0--
IMM DIR EXT IX2 - IX1 IX SP1 SP2 DIR INH INH IX1 IX SP1 DIR INH INH IX1 IX SP1 DD DIX+ - IMD IX+D DIR INH INH IX1 IX SP1
Logical Shift Left (Same as ASL)
C b7 b0
0
--
38 dd 48 58 68 ff 78 9E68 ff 34 dd 44 54 64 ff 74 9E64 ff 4E 5E 6E 7E 42 30 dd 40 50 60 ff 70 9E60 ff 9D 62 AA BA CA DA EA FA 9EEA 9EDA 87 8B 89 ii dd hh ll ee ff ff ff ee ff dd dd dd ii dd dd
Logical Shift Right
0 b7 b0
C
--0
Move Unsigned multiply
(M)Destination (M)Source H:X (H:X) + 1 (IX+D, DIX+) X:A (X) x (A) M -(M) = $00 - (M) A -(A) = $00 - (A) X -(X) = $00 - (X) M -(M) = $00 - (M) M -(M) = $00 - (M) None A (A[3:0]:A[7:4])
0--
- 0 - - - 0 INH
Negate (Two's Complement)
--
No Operation Nibble Swap A
- - - - - - INH - - - - - - INH IMM DIR EXT IX2 - IX1 IX SP1 SP2
Inclusive OR A and M
A (A) | (M)
0--
Push A onto Stack Push H onto Stack Push X onto Stack
Push (A); SP (SP) - 1 Push (H); SP (SP) - 1 Push (X); SP (SP) - 1
- - - - - - INH - - - - - - INH - - - - - - INH
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 69
Cycles
2 3 4 3 2 4 5 6 5 4 2 3 4 4 3 2 4 5 3 4 2 3 4 4 3 2 4 5 4 1 1 4 3 5 4 1 1 4 3 5 5 4 4 4 5 4 1 1 4 3 5 1 3 2 3 4 4 3 2 4 5 2 2 2
Effect on CCR
Operand
Central Processor Unit (CPU)
Table 7-1. Instruction Set Summary (Sheet 5 of 6)
Address Mode Opcode Source Form
PULA PULH PULX ROL opr ROLA ROLX ROL opr,X ROL ,X ROL opr,SP ROR opr RORA RORX ROR opr,X ROR ,X ROR opr,SP RSP
Operation
Pull A from Stack Pull H from Stack Pull X from Stack
Description
SP (SP + 1); Pull (A) SP (SP + 1); Pull (H) SP (SP + 1); Pull (X)
VH I NZC
- - - - - - INH - - - - - - INH - - - - - - INH DIR INH INH IX1 IX SP1 DIR INH INH IX1 IX SP1
86 8A 88 39 dd 49 59 69 ff 79 9E69 ff 36 dd 46 56 66 ff 76 9E66 ff 9C
Rotate Left through Carry
C b7 b0
--
Rotate Right through Carry
b7 b0
C
--
Reset Stack Pointer
SP $FF SP (SP) + 1; Pull (CCR) SP (SP) + 1; Pull (A) SP (SP) + 1; Pull (X) SP (SP) + 1; Pull (PCH) SP (SP) + 1; Pull (PCL) SP SP + 1; Pull (PCH) SP SP + 1; Pull (PCL)
- - - - - - INH
RTI
Return from Interrupt
INH
80
RTS SBC #opr SBC opr SBC opr SBC opr,X SBC opr,X SBC ,X SBC opr,SP SBC opr,SP SEC SEI STA opr STA opr STA opr,X STA opr,X STA ,X STA opr,SP STA opr,SP STHX opr STOP STX opr STX opr STX opr,X STX opr,X STX ,X STX opr,SP STX opr,SP SUB #opr SUB opr SUB opr SUB opr,X SUB opr,X SUB ,X SUB opr,SP SUB opr,SP
Return from Subroutine
- - - - - - INH IMM DIR EXT IX2 IX1 IX SP1 SP2
81 A2 B2 C2 D2 E2 F2 9EE2 9ED2 99 9B B7 C7 D7 E7 F7 9EE7 9ED7 35 8E BF CF DF EF FF 9EEF 9EDF A0 B0 C0 D0 E0 F0 9EE0 9ED0 dd hh ll ee ff ff ff ee ff ii dd hh ll ee ff ff ff ee ff dd hh ll ee ff ff ff ee ff dd ii dd hh ll ee ff ff ff ee ff
Subtract with Carry
A (A) - (M) - (C)
--
Set Carry Bit Set Interrupt Mask
C1 I1
- - - - - 1 INH - - 1 - - - INH DIR EXT IX2 - IX1 IX SP1 SP2 - DIR
Store A in M
M (A)
0--
Store H:X in M Enable Interrupts, Stop Processing, Refer to MCU Documentation
(M:M + 1) (H:X) I 0; Stop Processing
0--
- - 0 - - - INH DIR EXT IX2 - IX1 IX SP1 SP2 IMM DIR EXT IX2 IX1 IX SP1 SP2
Store X in M
M (X)
0--
Subtract
A (A) - (M)
--
MC68HC908QY/QT Family Data Sheet, Rev. 5 70 Freescale Semiconductor
Cycles
2 2 2 4 1 1 4 3 5 4 1 1 4 3 5 1 7 4 2 3 4 4 3 2 4 5 1 2 3 4 4 3 2 4 5 4 1 3 4 4 3 2 4 5 2 3 4 4 3 2 4 5
Effect on CCR
Operand
Opcode Map
Table 7-1. Instruction Set Summary (Sheet 6 of 6)
Address Mode Opcode Source Form Operation Description
PC (PC) + 1; Push (PCL) SP (SP) - 1; Push (PCH) SP (SP) - 1; Push (X) SP (SP) - 1; Push (A) SP (SP) - 1; Push (CCR) SP (SP) - 1; I 1 PCH Interrupt Vector High Byte PCL Interrupt Vector Low Byte CCR (A) X (A) A (CCR)
VH I NZC
SWI
Software Interrupt
- - 1 - - - INH
83
TAP TAX TPA TST opr TSTA TSTX TST opr,X TST ,X TST opr,SP TSX TXA TXS WAIT A C CCR dd dd rr DD DIR DIX+ ee ff EXT ff H H hh ll I ii IMD IMM INH IX IX+ IX+D IX1 IX1+ IX2 M N
Transfer A to CCR Transfer A to X Transfer CCR to A
INH - - - - - - INH - - - - - - INH DIR INH INH - IX1 IX SP1
84 97 85 3D dd 4D 5D 6D ff 7D 9E6D ff 95 9F 94 8F
Test for Negative or Zero
(A) - $00 or (X) - $00 or (M) - $00
0--
Transfer SP to H:X Transfer X to A Transfer H:X to SP Enable Interrupts; Wait for Interrupt
H:X (SP) + 1 A (X) (SP) (H:X) - 1 I bit 0; Inhibit CPU clocking until interrupted n opr PC PCH PCL REL rel rr SP1 SP2 SP U V X Z & |
- - - - - - INH - - - - - - INH - - - - - - INH - - 0 - - - INH
Accumulator Carry/borrow bit Condition code register Direct address of operand Direct address of operand and relative offset of branch instruction Direct to direct addressing mode Direct addressing mode Direct to indexed with post increment addressing mode High and low bytes of offset in indexed, 16-bit offset addressing Extended addressing mode Offset byte in indexed, 8-bit offset addressing Half-carry bit Index register high byte High and low bytes of operand address in extended addressing Interrupt mask Immediate operand byte Immediate source to direct destination addressing mode Immediate addressing mode Inherent addressing mode Indexed, no offset addressing mode Indexed, no offset, post increment addressing mode Indexed with post increment to direct addressing mode Indexed, 8-bit offset addressing mode Indexed, 8-bit offset, post increment addressing mode Indexed, 16-bit offset addressing mode Memory location Negative bit
() -( ) #
? : --
Any bit Operand (one or two bytes) Program counter Program counter high byte Program counter low byte Relative addressing mode Relative program counter offset byte Relative program counter offset byte Stack pointer, 8-bit offset addressing mode Stack pointer 16-bit offset addressing mode Stack pointer Undefined Overflow bit Index register low byte Zero bit Logical AND Logical OR Logical EXCLUSIVE OR Contents of Negation (two's complement) Immediate value Sign extend Loaded with If Concatenated with Set or cleared Not affected
7.8 Opcode Map
See Table 7-2.
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 71
Cycles
9 2 1 1 3 1 1 3 2 4 2 1 2 1
Effect on CCR
Operand
72
Bit Manipulation DIR DIR
MSB LSB
Central Processor Unit (CPU)
Table 7-2. Opcode Map
Branch REL 2 3 BRA 2 REL 3 BRN 2 REL 3 BHI 2 REL 3 BLS 2 REL 3 BCC 2 REL 3 BCS 2 REL 3 BNE 2 REL 3 BEQ 2 REL 3 BHCC 2 REL 3 BHCS 2 REL 3 BPL 2 REL 3 BMI 2 REL 3 BMC 2 REL 3 BMS 2 REL 3 BIL 2 REL 3 BIH 2 REL DIR 3 INH 4 Read-Modify-Write INH IX1 5 1 NEGX 1 INH 4 CBEQX 3 IMM 7 DIV 1 INH 1 COMX 1 INH 1 LSRX 1 INH 4 LDHX 2 DIR 1 RORX 1 INH 1 ASRX 1 INH 1 LSLX 1 INH 1 ROLX 1 INH 1 DECX 1 INH 3 DBNZX 2 INH 1 INCX 1 INH 1 TSTX 1 INH 4 MOV 2 DIX+ 1 CLRX 1 INH 6 4 NEG 2 IX1 5 CBEQ 3 IX1+ 3 NSA 1 INH 4 COM 2 IX1 4 LSR 2 IX1 3 CPHX 3 IMM 4 ROR 2 IX1 4 ASR 2 IX1 4 LSL 2 IX1 4 ROL 2 IX1 4 DEC 2 IX1 5 DBNZ 3 IX1 4 INC 2 IX1 3 TST 2 IX1 4 MOV 3 IMD 3 CLR 2 IX1 SP1 9E6 IX 7 Control INH INH 8 9 IMM A 2 SUB 2 IMM 2 CMP 2 IMM 2 SBC 2 IMM 2 CPX 2 IMM 2 AND 2 IMM 2 BIT 2 IMM 2 LDA 2 IMM 2 AIS 2 IMM 2 EOR 2 IMM 2 ADC 2 IMM 2 ORA 2 IMM 2 ADD 2 IMM DIR B EXT C 4 SUB 3 EXT 4 CMP 3 EXT 4 SBC 3 EXT 4 CPX 3 EXT 4 AND 3 EXT 4 BIT 3 EXT 4 LDA 3 EXT 4 STA 3 EXT 4 EOR 3 EXT 4 ADC 3 EXT 4 ORA 3 EXT 4 ADD 3 EXT 3 JMP 3 EXT 5 JSR 3 EXT 4 LDX 3 EXT 4 STX 3 EXT Register/Memory IX2 SP2 D 4 SUB 3 IX2 4 CMP 3 IX2 4 SBC 3 IX2 4 CPX 3 IX2 4 AND 3 IX2 4 BIT 3 IX2 4 LDA 3 IX2 4 STA 3 IX2 4 EOR 3 IX2 4 ADC 3 IX2 4 ORA 3 IX2 4 ADD 3 IX2 4 JMP 3 IX2 6 JSR 3 IX2 4 LDX 3 IX2 4 STX 3 IX2 9ED 5 SUB 4 SP2 5 CMP 4 SP2 5 SBC 4 SP2 5 CPX 4 SP2 5 AND 4 SP2 5 BIT 4 SP2 5 LDA 4 SP2 5 STA 4 SP2 5 EOR 4 SP2 5 ADC 4 SP2 5 ORA 4 SP2 5 ADD 4 SP2 IX1 E SP1 9EE 4 SUB 3 SP1 4 CMP 3 SP1 4 SBC 3 SP1 4 CPX 3 SP1 4 AND 3 SP1 4 BIT 3 SP1 4 LDA 3 SP1 4 STA 3 SP1 4 EOR 3 SP1 4 ADC 3 SP1 4 ORA 3 SP1 4 ADD 3 SP1 IX F 0 5 BRSET0 3 DIR 5 BRCLR0 3 DIR 5 BRSET1 3 DIR 5 BRCLR1 3 DIR 5 BRSET2 3 DIR 5 BRCLR2 3 DIR 5 BRSET3 3 DIR 5 BRCLR3 3 DIR 5 BRSET4 3 DIR 5 BRCLR4 3 DIR 5 BRSET5 3 DIR 5 BRCLR5 3 DIR 5 BRSET6 3 DIR 5 BRCLR6 3 DIR 5 BRSET7 3 DIR 5 BRCLR7 3 DIR 1 4 BSET0 2 DIR 4 BCLR0 2 DIR 4 BSET1 2 DIR 4 BCLR1 2 DIR 4 BSET2 2 DIR 4 BCLR2 2 DIR 4 BSET3 2 DIR 4 BCLR3 2 DIR 4 BSET4 2 DIR 4 BCLR4 2 DIR 4 BSET5 2 DIR 4 BCLR5 2 DIR 4 BSET6 2 DIR 4 BCLR6 2 DIR 4 BSET7 2 DIR 4 BCLR7 2 DIR
0 1 2 3
4 5 6 7 8 9 A B C D E
F
4 1 NEG NEGA 2 DIR 1 INH 5 4 CBEQ CBEQA 3 DIR 3 IMM 5 MUL 1 INH 4 1 COM COMA 2 DIR 1 INH 4 1 LSR LSRA 2 DIR 1 INH 4 3 STHX LDHX 2 DIR 3 IMM 4 1 ROR RORA 2 DIR 1 INH 4 1 ASR ASRA 2 DIR 1 INH 4 1 LSL LSLA 2 DIR 1 INH 4 1 ROL ROLA 2 DIR 1 INH 4 1 DEC DECA 2 DIR 1 INH 5 3 DBNZ DBNZA 3 DIR 2 INH 4 1 INC INCA 2 DIR 1 INH 3 1 TST TSTA 2 DIR 1 INH 5 MOV 3 DD 3 1 CLR CLRA 2 DIR 1 INH
5 3 NEG NEG 3 SP1 1 IX 6 4 CBEQ CBEQ 4 SP1 2 IX+ 2 DAA 1 INH 5 3 COM COM 3 SP1 1 IX 5 3 LSR LSR 3 SP1 1 IX 4 CPHX 2 DIR 5 3 ROR ROR 3 SP1 1 IX 5 3 ASR ASR 3 SP1 1 IX 5 3 LSL LSL 3 SP1 1 IX 5 3 ROL ROL 3 SP1 1 IX 5 3 DEC DEC 3 SP1 1 IX 6 4 DBNZ DBNZ 4 SP1 2 IX 5 3 INC INC 3 SP1 1 IX 4 2 TST TST 3 SP1 1 IX 4 MOV 2 IX+D 4 2 CLR CLR 3 SP1 1 IX
7 3 RTI BGE 1 INH 2 REL 4 3 RTS BLT 1 INH 2 REL 3 BGT 2 REL 9 3 SWI BLE 1 INH 2 REL 2 2 TAP TXS 1 INH 1 INH 1 2 TPA TSX 1 INH 1 INH 2 PULA 1 INH 2 1 PSHA TAX 1 INH 1 INH 2 1 PULX CLC 1 INH 1 INH 2 1 PSHX SEC 1 INH 1 INH 2 2 PULH CLI 1 INH 1 INH 2 2 PSHH SEI 1 INH 1 INH 1 1 CLRH RSP 1 INH 1 INH 1 NOP 1 INH 1 STOP * 1 INH 1 1 WAIT TXA 1 INH 1 INH
3 SUB 2 DIR 3 CMP 2 DIR 3 SBC 2 DIR 3 CPX 2 DIR 3 AND 2 DIR 3 BIT 2 DIR 3 LDA 2 DIR 3 STA 2 DIR 3 EOR 2 DIR 3 ADC 2 DIR 3 ORA 2 DIR 3 ADD 2 DIR 2 JMP 2 DIR 4 4 BSR JSR 2 REL 2 DIR 2 3 LDX LDX 2 IMM 2 DIR 2 3 AIX STX 2 IMM 2 DIR
MSB LSB
3 SUB 2 IX1 3 CMP 2 IX1 3 SBC 2 IX1 3 CPX 2 IX1 3 AND 2 IX1 3 BIT 2 IX1 3 LDA 2 IX1 3 STA 2 IX1 3 EOR 2 IX1 3 ADC 2 IX1 3 ORA 2 IX1 3 ADD 2 IX1 3 JMP 2 IX1 5 JSR 2 IX1 5 3 LDX LDX 4 SP2 2 IX1 5 3 STX STX 4 SP2 2 IX1
2 SUB 1 IX 2 CMP 1 IX 2 SBC 1 IX 2 CPX 1 IX 2 AND 1 IX 2 BIT 1 IX 2 LDA 1 IX 2 STA 1 IX 2 EOR 1 IX 2 ADC 1 IX 2 ORA 1 IX 2 ADD 1 IX 2 JMP 1 IX 4 JSR 1 IX 4 2 LDX LDX 3 SP1 1 IX 4 2 STX STX 3 SP1 1 IX
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor
Inherent REL Relative Immediate IX Indexed, No Offset Direct IX1 Indexed, 8-Bit Offset Extended IX2 Indexed, 16-Bit Offset Direct-Direct IMD Immediate-Direct Indexed-Direct DIX+ Direct-Indexed *Pre-byte for stack pointer indexed instructions
INH IMM DIR EXT DD IX+D
SP1 Stack Pointer, 8-Bit Offset SP2 Stack Pointer, 16-Bit Offset IX+ Indexed, No Offset with Post Increment IX1+ Indexed, 1-Byte Offset with Post Increment
0
High Byte of Opcode in Hexadecimal
Low Byte of Opcode in Hexadecimal
0
5 Cycles BRSET0 Opcode Mnemonic 3 DIR Number of Bytes / Addressing Mode
Chapter 8 External Interrupt (IRQ)
8.1 Introduction
The IRQ pin (external interrupt), shared with PTA2 (general purpose input) and keyboard interrupt (KBI), provides a maskable interrupt input
8.2 Features
Features of the IRQ module include the following: * * * * * External interrupt pin, IRQ IRQ interrupt control bits Programmable edge-only or edge and level interrupt sensitivity Automatic interrupt acknowledge Selectable internal pullup resistor
8.3 Functional Description
IRQ pin functionality is enabled by setting configuration register 2 (CONFIG2) IRQEN bit accordingly. A zero disables the IRQ function and PTA2 will assume the other shared functionalities. A one enables the IRQ function. A low level applied to the external interrupt request (IRQ) pin can latch a CPU interrupt request. Figure 8-2 shows the structure of the IRQ module. Interrupt signals on the IRQ pin are latched into the IRQ latch. The IRQ latch remains set until one of the following actions occurs: * * * IRQ vector fetch -- An IRQ vector fetch automatically generates an interrupt acknowledge signal that clears the IRQ latch. Software clear -- Software can clear the IRQ latch by writing a 1 to the ACK bit in the interrupt status and control register (INTSCR). Reset -- A reset automatically clears the IRQ latch.
The external interrupt pin is falling-edge-triggered out of reset and is software-configurable to be either falling-edge or falling-edge and low-level triggered. The MODE bit in INTSCR controls the triggering sensitivity of the IRQ pin.
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 73
External Interrupt (IRQ)
PTA0/AD0/TCH0/KBI0 PTA1/AD1/TCH1/KBI1 DDRA PTA PTA2/IRQ/KBI2/TCLK PTA3/RST/KBI3 PTA4/OSC2/AD2/KBI4 PTA5/OSC1/AD3/KBI5 M68HC08 CPU PTB0 PTB1 PTB2 PTB3 PTB4 PTB5 PTB6 PTB7 CLOCK GENERATOR (OSCILLATOR)
SYSTEM INTEGRATION MODULE SINGLE INTERRUPT MODULE BREAK MODULE POWER-ON RESET MODULE MC68HC908QY4 AND MC68HC908QT4 4096 BYTES MC68HC908QY2, MC68HC908QY1, MC68HC908QT2, AND MC68HC908QT1: 1536 BYTES USER FLASH KEYBOARD INTERRUPT MODULE 16-BIT TIMER MODULE COP MODULE VDD
8-BIT ADC
128 BYTES RAM
POWER SUPPLY VSS
DDRB
PTB
MONITOR ROM
RST, IRQ: Pins have internal (about 30K Ohms) pull up PTA[0:5]: High current sink and source capability PTA[0:5]: Pins have programmable keyboard interrupt and pull up PTB[0:7]: Not available on 8-pin devices - MC68HC908QT1, MC68HC908QT2, and MC68HC908QT4 (see note in 12.1 Introduction) ADC: Not available on the MC68HC908QY1 and MC68HC908QT1
Figure 8-1. Block Diagram Highlighting IRQ Block and Pins
When set, the IMASK bit in INTSCR masks the IRQ interrupt request. A latched interrupt request is not presented to the interrupt priority logic unless IMASK is clear. NOTE The interrupt mask (I) in the condition code register (CCR) masks all interrupt requests, including the IRQ interrupt request. A falling edge on the IRQ pin can latch an interrupt request into the IRQ latch. An IRQ vector fetch, software clear, or reset clears the IRQ latch.
MC68HC908QY/QT Family Data Sheet, Rev. 5 74 Freescale Semiconductor
Functional Description
ACK RESET INTERNAL ADDRESS BUS VECTOR FETCH DECODER VDD IRQPUD INTERNAL PULLUP DEVICE VDD D IRQ CLR Q SYNCHRONIZER IRQF TO CPU FOR BIL/BIH INSTRUCTIONS
CK IRQ LATCH IMASK
IRQ INTERRUPT REQUEST
MODE HIGH VOLTAGE DETECT TO MODE SELECT LOGIC
Figure 8-2. IRQ Module Block Diagram
8.3.1 MODE = 1
If the MODE bit is set, the IRQ pin is both falling edge sensitive and low level sensitive. With MODE set, both of the following actions must occur to clear the IRQ interrupt request: * Return of the IRQ pin to a high level. As long as the IRQ pin is low, the IRQ request remains active. * IRQ vector fetch or software clear. An IRQ vector fetch generates an interrupt acknowledge signal to clear the IRQ latch. Software generates the interrupt acknowledge signal by writing a 1 to ACK in INTSCR. The ACK bit is useful in applications that poll the IRQ pin and require software to clear the IRQ latch. Writing to ACK prior to leaving an interrupt service routine can also prevent spurious interrupts due to noise. Setting ACK does not affect subsequent transitions on the IRQ pin. A falling edge that occurs after writing to ACK latches another interrupt request. If the IRQ mask bit, IMASK, is clear, the CPU loads the program counter with the IRQ vector address. The IRQ vector fetch or software clear and the return of the IRQ pin to a high level may occur in any order. The interrupt request remains pending as long as the IRQ pin is low. A reset will clear the IRQ latch and the MODE control bit, thereby clearing the interrupt even if the pin stays low. Use the BIH or BIL instruction to read the logic level on the IRQ pin.
8.3.2 MODE = 0
If the MODE bit is clear, the IRQ pin is falling edge sensitive only. With MODE clear, an IRQ vector fetch or software clear immediately clears the IRQ latch. The IRQF bit in INTSCR can be read to check for pending interrupts. The IRQF bit is not affected by IMASK, which makes it useful in applications where polling is preferred. NOTE When using the level-sensitive interrupt trigger, avoid false IRQ interrupts by masking interrupt requests in the interrupt routine.
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 75
External Interrupt (IRQ)
8.4 Interrupts
The following IRQ source can generate interrupt requests: * Interrupt flag (IRQF) -- The IRQF bit is set when the IRQ pin is asserted based on the IRQ mode. The IRQ interrupt mask bit, IMASK, is used to enable or disable IRQ interrupt requests.
8.5 Low-Power Modes
The WAIT and STOP instructions put the MCU in low power-consumption standby modes.
8.5.1 Wait Mode
The IRQ module remains active in wait mode. Clearing IMASK in INTSCR enables IRQ interrupt requests to bring the MCU out of wait mode.
8.5.2 Stop Mode
The IRQ module remains active in stop mode. Clearing IMASK in INTSCR enables IRQ interrupt requests to bring the MCU out of stop mode.
8.6 IRQ Module During Break Interrupts
The system integration module (SIM) controls whether status bits in other modules can be cleared during the break state. The BCFE bit in the break flag control register (BFCR) enables software to clear status bits during the break state. See Chapter 13 System Integration Module (SIM). To allow software to clear status bits during a break interrupt, write a 1 to the BCFE bit. If a status bit is cleared during the break state, it remains cleared when the MCU exits the break state. To protect status bits during the break state, write a 0 to BCFE. With BCFE cleared (its default state), software can read and write registers during the break state without affecting status bits. Some status bits have a two-step read/write clearing procedure. If software does the first step on such a bit before the break, the bit cannot change during the break state as long as BCFE is cleared. After the break, doing the second step clears the status bit.
8.7 I/O Signals
The IRQ module shares its pin with the keyboard interrupt, input/output ports, and timer interface modules. NOTE When the IRQ function is enabled in the CONFIG2 register, the BIH and BIL instructions can be used to read the logic level on the IRQ pin. If the IRQ function is disabled, these instructions will behave as if the IRQ pin is a logic 1, regardless of the actual level on the pin. Conversely, when the IRQ function is enabled, bit 2 of the port A data register will always read a 0. When using the level-sensitive interrupt trigger, avoid false interrupts by masking interrupt requests in the interrupt routine. An internal pullup resistor to VDD is connected to the IRQ pin; this can be disabled by setting the IRQPUD bit in the CONFIG2 register ($001E).
MC68HC908QY/QT Family Data Sheet, Rev. 5 76 Freescale Semiconductor
Registers
8.7.1 IRQ Input Pins (IRQ)
The IRQ pin provides a maskable external interrupt source. The IRQ pin contains an internal pullup device.
8.8 Registers
The IRQ status and control register (INTSCR) controls and monitors operation of the IRQ module. See Chapter 5 Configuration Register (CONFIG). The INTSCR has the following functions: * Shows the state of the IRQ flag * Clears the IRQ latch * Masks the IRQ interrupt request * Controls triggering sensitivity of the IRQ interrupt pin
Address: $001D Bit 7 Read: Write: Reset: 0 0 0 0 0 = Unimplemented 0 6 0 5 0 4 0 3 IRQF 2 0 ACK 0 1 IMASK 0 Bit 0 MODE 0
Figure 8-3. IRQ Status and Control Register (INTSCR) IRQF -- IRQ Flag This read-only status bit is set when the IRQ interrupt is pending. 1 = IRQ interrupt pending 0 = IRQ interrupt not pending ACK -- IRQ Interrupt Request Acknowledge Bit Writing a 1 to this write-only bit clears the IRQ latch. ACK always reads as 0. IMASK -- IRQ Interrupt Mask Bit Writing a 1 to this read/write bit disables the IRQ interrupt request. 1 = IRQ interrupt request disabled 0 = IRQ interrupt request enabled MODE -- IRQ Edge/Level Select Bit This read/write bit controls the triggering sensitivity of the IRQ pin. 1 = IRQ interrupt request on falling edges and low levels 0 = IRQ interrupt request on falling edges only
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 77
External Interrupt (IRQ)
MC68HC908QY/QT Family Data Sheet, Rev. 5 78 Freescale Semiconductor
Chapter 9 Keyboard Interrupt Module (KBI)
9.1 Introduction
The keyboard interrupt module (KBI) provides six independently maskable external interrupts, which are accessible via the PTA0-PTA5 pins.
9.2 Features
Features of the keyboard interrupt module include: * Six keyboard interrupt pins with separate keyboard interrupt enable bits and one keyboard interrupt mask * Software configurable pullup device if input pin is configured as input port bit * Programmable edge-only or edge and level interrupt sensitivity * Exit from low-power modes
9.3 Functional Description
The keyboard interrupt module controls the enabling/disabling of interrupt functions on the six port A pins. These six pins can be enabled/disabled independently of each other. Refer to Figure 9-2.
9.3.1 Keyboard Operation
Writing to the KBIE0-KBIE5 bits in the keyboard interrupt enable register (KBIER) independently enables or disables each port A pin as a keyboard interrupt pin. Enabling a keyboard interrupt pin in port A also enables its internal pullup device irrespective of PTAPUEx bits in the port A input pullup enable register (see 12.2.3 Port A Input Pullup Enable Register). A logic 0 applied to an enabled keyboard interrupt pin latches a keyboard interrupt request. A keyboard interrupt is latched when one or more keyboard interrupt inputs goes low after all were high. The MODEK bit in the keyboard status and control register controls the triggering mode of the keyboard interrupt. * If the keyboard interrupt is edge-sensitive only, a falling edge on a keyboard interrupt input does not latch an interrupt request if another keyboard pin is already low. To prevent losing an interrupt request on one input because another input is still low, software can disable the latter input while it is low. * If the keyboard interrupt is falling edge and low-level sensitive, an interrupt request is present as long as any keyboard interrupt input is low.
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 79
Keyboard Interrupt Module (KBI)
PTA0/AD0/TCH0/KBI0 PTA1/AD1/TCH1/KBI1 DDRA PTA PTA2/IRQ/KBI2/TCLK PTA3/RST/KBI3 PTA4/OSC2/AD2/KBI4 PTA5/OSC1/AD3/KBI5 M68HC08 CPU PTB0 PTB1 PTB2 PTB3 PTB4 PTB5 PTB6 PTB7 CLOCK GENERATOR (OSCILLATOR)
SYSTEM INTEGRATION MODULE SINGLE INTERRUPT MODULE BREAK MODULE POWER-ON RESET MODULE MC68HC908QY4 AND MC68HC908QT4 4096 BYTES MC68HC908QY2, MC68HC908QY1, MC68HC908QT2, AND MC68HC908QT1: 1536 BYTES USER FLASH KEYBOARD INTERRUPT MODULE 16-BIT TIMER MODULE COP MODULE VDD
8-BIT ADC
128 BYTES RAM
POWER SUPPLY VSS
DDRB
PTB
MONITOR ROM
RST, IRQ: Pins have internal (about 30K Ohms) pull up PTA[0:5]: High current sink and source capability PTA[0:5]: Pins have programmable keyboard interrupt and pull up PTB[0:7]: Not available on 8-pin devices - MC68HC908QT1, MC68HC908QT2, and MC68HC908QT4 (see note in 12.1 Introduction) ADC: Not available on the MC68HC908QY1 and MC68HC908QT1
Figure 9-1. Block Diagram Highlighting KBI Block and Pins
MC68HC908QY/QT Family Data Sheet, Rev. 5 80 Freescale Semiconductor
Functional Description
INTERNAL BUS
VECTOR FETCH DECODER KBI0 VDD ACKK RESET D CLR Q SYNCHRONIZER CK KEYBOARD INTERRUPT REQUEST KEYF
KBIE0 TO PULLUP ENABLE
. . .
KBI5
KEYBOARD INTERRUPT FF MODEK KBIE5
IMASKK
TO PULLUP ENABLE AWUIREQ(1) 1. For AWUGEN logic refer to Figure 4-1. Auto Wakeup Interrupt Request Generation Logic.
Figure 9-2. Keyboard Interrupt Block Diagram If the MODEK bit is set, the keyboard interrupt inputs are both falling edge and low-level sensitive, and both of the following actions must occur to clear a keyboard interrupt request: * Vector fetch or software clear -- A vector fetch generates an interrupt acknowledge signal to clear the interrupt request. Software may generate the interrupt acknowledge signal by writing a 1 to the ACKK bit in the keyboard status and control register (KBSCR). The ACKK bit is useful in applications that poll the keyboard interrupt inputs and require software to clear the keyboard interrupt request. Writing to the ACKK bit prior to leaving an interrupt service routine can also prevent spurious interrupts due to noise. Setting ACKK does not affect subsequent transitions on the keyboard interrupt inputs. A falling edge that occurs after writing to the ACKK bit latches another interrupt request. If the keyboard interrupt mask bit, IMASKK, is clear, the central processor unit (CPU) loads the program counter with the vector address at locations $FFE0 and $FFE1. * Return of all enabled keyboard interrupt inputs to logic 1 -- As long as any enabled keyboard interrupt pin is at logic 0, the keyboard interrupt remains set. The auto wakeup interrupt input, AWUIREQ, will be cleared only by writing to ACKK bit in KBSCR or reset. The vector fetch or software clear and the return of all enabled keyboard interrupt pins to logic 1 may occur in any order. If the MODEK bit is clear, the keyboard interrupt pin is falling-edge sensitive only. With MODEK clear, a vector fetch or software clear immediately clears the keyboard interrupt request. Reset clears the keyboard interrupt request and the MODEK bit, clearing the interrupt request even if a keyboard interrupt input stays at logic 0. The keyboard flag bit (KEYF) in the keyboard status and control register can be used to see if a pending interrupt exists. The KEYF bit is not affected by the keyboard interrupt mask bit (IMASKK) which makes it useful in applications where polling is preferred.
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 81
Keyboard Interrupt Module (KBI)
To determine the logic level on a keyboard interrupt pin, use the data direction register to configure the pin as an input and then read the data register. NOTE Setting a keyboard interrupt enable bit (KBIEx) forces the corresponding keyboard interrupt pin to be an input, overriding the data direction register. However, the data direction register bit must be a 0 for software to read the pin.
9.3.2 Keyboard Initialization
When a keyboard interrupt pin is enabled, it takes time for the internal pullup to reach a logic 1. Therefore a false interrupt can occur as soon as the pin is enabled. To prevent a false interrupt on keyboard initialization: 1. Mask keyboard interrupts by setting the IMASKK bit in the keyboard status and control register. 2. Enable the KBI pins by setting the appropriate KBIEx bits in the keyboard interrupt enable register. 3. Write to the ACKK bit in the keyboard status and control register to clear any false interrupts. 4. Clear the IMASKK bit. An interrupt signal on an edge-triggered pin can be acknowledged immediately after enabling the pin. An interrupt signal on an edge- and level-triggered interrupt pin must be acknowledged after a delay that depends on the external load. Another way to avoid a false interrupt: 1. Configure the keyboard pins as outputs by setting the appropriate DDRA bits in the data direction register A. 2. Write 1s to the appropriate port A data register bits. 3. Enable the KBI pins by setting the appropriate KBIEx bits in the keyboard interrupt enable register.
9.4 Wait Mode
The keyboard module remains active in wait mode. Clearing the IMASKK bit in the keyboard status and control register enables keyboard interrupt requests to bring the MCU out of wait mode.
9.5 Stop Mode
The keyboard module remains active in stop mode. Clearing the IMASKK bit in the keyboard status and control register enables keyboard interrupt requests to bring the MCU out of stop mode.
9.6 Keyboard Module During Break Interrupts
The system integration module (SIM) controls whether the keyboard interrupt latch can be cleared during the break state. The BCFE bit in the break flag control register (BFCR) enables software to clear status bits during the break state. To allow software to clear the keyboard interrupt latch during a break interrupt, write a 1 to the BCFE bit. If a latch is cleared during the break state, it remains cleared when the MCU exits the break state.
MC68HC908QY/QT Family Data Sheet, Rev. 5 82 Freescale Semiconductor
Input/Output Registers
To protect the latch during the break state, write a 0 to the BCFE bit. With BCFE at 0 (its default state), writing to the keyboard acknowledge bit (ACKK) in the keyboard status and control register during the break state has no effect.
9.7 Input/Output Registers
The following I/O registers control and monitor operation of the keyboard interrupt module: * Keyboard interrupt status and control register (KBSCR) * Keyboard interrupt enable register (KBIER)
9.7.1 Keyboard Status and Control Register
The keyboard status and control register (KBSCR): * Flags keyboard interrupt requests * Acknowledges keyboard interrupt requests * Masks keyboard interrupt requests * Controls keyboard interrupt triggering sensitivity
Address: $001A Bit 7 Read: Write: Reset: 0 0 0 0 0 = Unimplemented 0 6 0 5 0 4 0 3 KEYF 2 0 ACKK 0 1 IMASKK 0 Bit 0 MODEK 0
Figure 9-3. Keyboard Status and Control Register (KBSCR) Bits 7-4 -- Not used These read-only bits always read as 0s. KEYF -- Keyboard Flag Bit This read-only bit is set when a keyboard interrupt is pending on port A or auto wakeup. Reset clears the KEYF bit. 1 = Keyboard interrupt pending 0 = No keyboard interrupt pending ACKK -- Keyboard Acknowledge Bit Writing a 1 to this write-only bit clears the keyboard interrupt request on port A and auto wakeup logic. ACKK always reads as 0. Reset clears ACKK. IMASKK-- Keyboard Interrupt Mask Bit Writing a 1 to this read/write bit prevents the output of the keyboard interrupt mask from generating interrupt requests on port A or auto wakeup. Reset clears the IMASKK bit. 1 = Keyboard interrupt requests masked 0 = Keyboard interrupt requests not masked MODEK -- Keyboard Triggering Sensitivity Bit This read/write bit controls the triggering sensitivity of the keyboard interrupt pins on port A and auto wakeup. Reset clears MODEK. 1 = Keyboard interrupt requests on falling edges and low levels 0 = Keyboard interrupt requests on falling edges only
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 83
Keyboard Interrupt Module (KBI)
9.7.2 Keyboard Interrupt Enable Register
The port A keyboard interrupt enable register (KBIER) enables or disables each port A pin or auto wakeup to operate as a keyboard interrupt input.
Address: $001B Bit 7 Read: Write: Reset: 0 0 6 AWUIE 0 5 KBIE5 0 4 KBIE4 0 3 KBIE3 0 2 KBIE2 0 1 KBIE1 0 Bit 0 KBIE0 0
= Unimplemented
Figure 9-4. Keyboard Interrupt Enable Register (KBIER) KBIE5-KBIE0 -- Port A Keyboard Interrupt Enable Bits Each of these read/write bits enables the corresponding keyboard interrupt pin on port A to latch interrupt requests. Reset clears the keyboard interrupt enable register. 1 = KBIx pin enabled as keyboard interrupt pin 0 = KBIx pin not enabled as keyboard interrupt pin NOTE AWUIE bit is not used in conjunction with the keyboard interrupt feature. To see a description of this bit, see Chapter 4 Auto Wakeup Module (AWU).
MC68HC908QY/QT Family Data Sheet, Rev. 5 84 Freescale Semiconductor
Chapter 10 Low-Voltage Inhibit (LVI)
10.1 Introduction
This section describes the low-voltage inhibit (LVI) module, which monitors the voltage on the VDD pin and can force a reset when the VDD voltage falls below the LVI trip falling voltage, VTRIPF.
10.2 Features
Features of the LVI module include: * Programmable LVI reset * Programmable power consumption * Selectable LVI trip voltage * Programmable stop mode operation
10.3 Functional Description
Figure 10-1 shows the structure of the LVI module. LVISTOP, LVIPWRD, LVI5OR3, and LVIRSTD are user selectable options found in the configuration register (CONFIG1). See Chapter 5 Configuration Register (CONFIG).
VDD STOP INSTRUCTION LVISTOP FROM CONFIG FROM CONFIG LVIRSTD LVIPWRD FROM CONFIG LOW VDD DETECTOR VDD > LVITRIP = 0 VDD LVITRIP = 1 LVIOUT LVI5OR3 FROM CONFIG LVI RESET
Figure 10-1. LVI Module Block Diagram The LVI is enabled out of reset. The LVI module contains a bandgap reference circuit and comparator. Clearing the LVI power disable bit, LVIPWRD, enables the LVI to monitor VDD voltage. Clearing the LVI reset disable bit, LVIRSTD, enables the LVI module to generate a reset when VDD falls below a voltage,
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 85
Low-Voltage Inhibit (LVI)
VTRIPF. Setting the LVI enable in stop mode bit, LVISTOP, enables the LVI to operate in stop mode. Setting the LVI 5-V or 3-V trip point bit, LVI5OR3, enables the trip point voltage, VTRIPF, to be configured for 5-V operation. Clearing the LVI5OR3 bit enables the trip point voltage, VTRIPF, to be configured for 3-V operation. The actual trip thresholds are specified in 16.5 5-V DC Electrical Characteristics and 16.9 3-V DC Electrical Characteristics. NOTE After a power-on reset, the LVI's default mode of operation is 3 volts. If a 5-V system is used, the user must set the LVI5OR3 bit to raise the trip point to 5-V operation. If the user requires 5-V mode and sets the LVI5OR3 bit after power-on reset while the VDD supply is not above the VTRIPR for 5-V mode, the microcontroller unit (MCU) will immediately go into reset. The next time the LVI releases the reset, the supply will be above the VTRIPR for 5-V mode. Once an LVI reset occurs, the MCU remains in reset until VDD rises above a voltage, VTRIPR, which causes the MCU to exit reset. See Chapter 13 System Integration Module (SIM) for the reset recovery sequence. The output of the comparator controls the state of the LVIOUT flag in the LVI status register (LVISR) and can be used for polling LVI operation when the LVI reset is disabled.
10.3.1 Polled LVI Operation
In applications that can operate at VDD levels below the VTRIPF level, software can monitor VDD by polling the LVIOUT bit. In the configuration register, the LVIPWRD bit must be cleared to enable the LVI module, and the LVIRSTD bit must be at set to disable LVI resets.
10.3.2 Forced Reset Operation
In applications that require VDD to remain above the VTRIPF level, enabling LVI resets allows the LVI module to reset the MCU when VDD falls below the VTRIPF level. In the configuration register, the LVIPWRD and LVIRSTD bits must be cleared to enable the LVI module and to enable LVI resets.
10.3.3 Voltage Hysteresis Protection
Once the LVI has triggered (by having VDD fall below VTRIPF), the LVI will maintain a reset condition until VDD rises above the rising trip point voltage, VTRIPR. This prevents a condition in which the MCU is continually entering and exiting reset if VDD is approximately equal to VTRIPF. VTRIPR is greater than VTRIPF by the hysteresis voltage, VHYS.
10.3.4 LVI Trip Selection
The LVI5OR3 bit in the configuration register selects whether the LVI is configured for 5-V or 3-V protection. NOTE The microcontroller is guaranteed to operate at a minimum supply voltage. The trip point (VTRIPF [5 V] or VTRIPF [3 V]) may be lower than this. See 16.5 5-V DC Electrical Characteristics and 16.9 3-V DC Electrical Characteristics for the actual trip point voltages.
MC68HC908QY/QT Family Data Sheet, Rev. 5 86 Freescale Semiconductor
LVI Status Register
10.4 LVI Status Register
The LVI status register (LVISR) indicates if the VDD voltage was detected below the VTRIPF level while LVI resets have been disabled.
Address: $FE0C Bit 7 Read: Write: Reset: 0 0 = Unimplemented 0 0 0 R 0 = Reserved 0 0 LVIOUT 6 0 5 0 4 0 3 0 2 0 1 0 Bit 0 R
Figure 10-2. LVI Status Register (LVISR) LVIOUT -- LVI Output Bit This read-only flag becomes set when the VDD voltage falls below the VTRIPF trip voltage and is cleared when VDD voltage rises above VTRIPR. The difference in these threshold levels results in a hysteresis that prevents oscillation into and out of reset (see Table 10-1). Reset clears the LVIOUT bit. Table 10-1. LVIOUT Bit Indication
VDD VDD > VTRIPR VDD < VTRIPF VTRIPF < VDD < VTRIPR LVIOUT 0 1 Previous value
10.5 LVI Interrupts
The LVI module does not generate interrupt requests.
10.6 Low-Power Modes
The STOP and WAIT instructions put the MCU in low power-consumption standby modes.
10.6.1 Wait Mode
If enabled, the LVI module remains active in wait mode. If enabled to generate resets, the LVI module can generate a reset and bring the MCU out of wait mode.
10.6.2 Stop Mode
When the LVIPWRD bit in the configuration register is cleared and the LVISTOP bit in the configuration register is set, the LVI module remains active in stop mode. If enabled to generate resets, the LVI module can generate a reset and bring the MCU out of stop mode.
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 87
Low-Voltage Inhibit (LVI)
MC68HC908QY/QT Family Data Sheet, Rev. 5 88 Freescale Semiconductor
Chapter 11 Oscillator Module (OSC)
11.1 Introduction
The oscillator module is used to provide a stable clock source for the microcontroller system and bus. The oscillator module generates two output clocks, BUSCLKX2 and BUSCLKX4. The BUSCLKX4 clock is used by the system integration module (SIM) and the computer operating properly module (COP). The BUSCLKX2 clock is divided by two in the SIM to be used as the bus clock for the microcontroller. Therefore the bus frequency will be one fourth of the BUSCLKX4 frequency.
11.2 Features
The oscillator has these four clock source options available: 1. Internal oscillator: An internally generated, fixed frequency clock, trimmable to 5%.This is the default option out of reset. 2. External oscillator: An external clock that can be driven directly into OSC1. 3. External RC: A built-in oscillator module (RC oscillator) that requires an external R connection only. The capacitor is internal to the chip. 4. External crystal: A built-in oscillator module (XTAL oscillator) that requires an external crystal or ceramic-resonator.
11.3 Functional Description
The oscillator contains these major subsystems: * Internal oscillator circuit * Internal or external clock switch control * External clock circuit * External crystal circuit * External RC clock circuit
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 89
Oscillator Module (OSC)
PTA0/AD0/TCH0/KBI0 PTA1/AD1/TCH1/KBI1 DDRA PTA PTA2/IRQ/KBI2/TCLK PTA3/RST/KBI3 PTA4/OSC2/AD2/KBI4 PTA5/OSC1/AD3/KBI5 M68HC08 CPU PTB0 PTB1 PTB2 PTB3 PTB4 PTB5 PTB6 PTB7 CLOCK GENERATOR (OSCILLATOR)
SYSTEM INTEGRATION MODULE SINGLE INTERRUPT MODULE BREAK MODULE POWER-ON RESET MODULE MC68HC908QY4 AND MC68HC908QT4 4096 BYTES MC68HC908QY2, MC68HC908QY1, MC68HC908QT2, AND MC68HC908QT1: 1536 BYTES USER FLASH KEYBOARD INTERRUPT MODULE 16-BIT TIMER MODULE COP MODULE VDD
8-BIT ADC
128 BYTES RAM
POWER SUPPLY VSS
DDRB
PTB
MONITOR ROM
RST, IRQ: Pins have internal (about 30K Ohms) pull up PTA[0:5]: High current sink and source capability PTA[0:5]: Pins have programmable keyboard interrupt and pull up PTB[0:7]: Not available on 8-pin devices - MC68HC908QT1, MC68HC908QT2, and MC68HC908QT4 (see note in 12.1 Introduction) ADC: Not available on the MC68HC908QY1 and MC68HC908QT1
Figure 11-1. Block Diagram Highlighting OSC Block and Pins
11.3.1 Internal Oscillator
The internal oscillator circuit is designed for use with no external components to provide a clock source with tolerance less than 25% untrimmed.An 8-bit trimming register allows adjustment to a tolerance of less than 5%. The internal oscillator will generate a clock of 12.8 MHz typical (INTCLK) resulting in a bus speed (internal clock / 4) of 3.2 MHz. 3.2 MHz came from the maximum bus speed guaranteed at 3 V which is 4 MHz.Since the internal oscillator will have a 25% tolerance (pre-trim), then the +25% case should not allow a frequency higher than 4 MHz: 3.2 MHz + 25% = 4 MHz Figure 11-3 shows how BUSCLKX4 is derived from INTCLK and, like the RC oscillator, OSC2 can output BUSCLKX4 by setting OSC2EN in PTAPUE register. See Chapter 12 Input/Output Ports (PORTS)
MC68HC908QY/QT Family Data Sheet, Rev. 5 90 Freescale Semiconductor
Functional Description
11.3.1.1 Internal Oscillator Trimming The 8-bit trimming register, OSCTRIM, allows a clock period adjust of +127 and -128 steps. Increasing OSCTRIM value increases the clock period. Trimming allows the internal clock frequency to be set to 12.8 MHz 5%. All devices are programmed with a trim value in a reserved FLASH location, $FFC0. This value can be copied from the FLASH to the OSCTRIM register ($0038) during reset initialization. Reset loads OSCTRIM with a default value of $80. WARNING Bulk FLASH erasure will set location $FFC0 to $FF and the factory programmed value will be lost. 11.3.1.2 Internal to External Clock Switching When external clock source (external OSC, RC, or XTAL) is desired, the user must perform the following steps: 1. For external crystal circuits only, OSCOPT[1:0] = 1:1: To help precharge an external crystal oscillator, set PTA4 (OSC2) as an output and drive high for several cycles. This may help the crystal circuit start more robustly. 2. Set CONFIG2 bits OSCOPT[1:0] according to . The oscillator module control logic will then set OSC1 as an external clock input and, if the external crystal option is selected, OSC2 will also be set as the clock output. 3. Create a software delay to wait the stabilization time needed for the selected clock source (crystal, resonator, RC) as recommended by the component manufacturer. A good rule of thumb for crystal oscillators is to wait 4096 cycles of the crystal frequency, i.e., for a 4-MHz crystal, wait approximately 1 msec. 4. After the manufacturer's recommended delay has elapsed, the ECGON bit in the OSC status register (OSCSTAT) needs to be set by the user software. 5. After ECGON set is detected, the OSC module checks for oscillator activity by waiting two external clock rising edges. 6. The OSC module then switches to the external clock. Logic provides a glitch free transition. 7. The OSC module first sets the ECGST bit in the OSCSTAT register and then stops the internal oscillator. NOTE Once transition to the external clock is done, the internal oscillator will only be reactivated with reset. No post-switch clock monitor feature is implemented (clock does not switch back to internal if external clock dies).
11.3.2 External Oscillator
The external clock option is designed for use when a clock signal is available in the application to provide a clock source to the microcontroller. The OSC1 pin is enabled as an input by the oscillator module. The clock signal is used directly to create BUSCLKX4 and also divided by two to create BUSCLKX2. In this configuration, the OSC2 pin cannot output BUSCLKX4.So the OSC2EN bit in the port A pullup enable register will be clear to enable PTA4 I/O functions on the pin
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 91
Oscillator Module (OSC)
11.3.3 XTAL Oscillator
The XTAL oscillator circuit is designed for use with an external crystal or ceramic resonator to provide an accurate clock source. In this configuration, the OSC2 pin is dedicated to the external crystal circuit. The OSC2EN bit in the port A pullup enable register has no effect when this clock mode is selected. In its typical configuration, the XTAL oscillator is connected in a Pierce oscillator configuration, as shown in Figure 11-2. This figure shows only the logical representation of the internal components and may not represent actual circuitry. The oscillator configuration uses five components: * Crystal, X1 * Fixed capacitor, C1 * Tuning capacitor, C2 (can also be a fixed capacitor) * Feedback resistor, RB * Series resistor, RS (optional) NOTE The series resistor (RS) is included in the diagram to follow strict Pierce oscillator guidelines and may not be required for all ranges of operation, especially with high frequency crystals. Refer to the crystal manufacturer's data for more information.
FROM SIM TO SIM BUSCLKX4 TO SIM BUSCLKX2
XTALCLK SIMOSCEN
/2
MCU OSC1 OSC2
RS(1) RB
X1
C1
C2
Note 1. RS can be zero (shorted) when used with higher-frequency crystals. Refer to manufacturer's data. See Chapter 16 Electrical Specifications for component value recommendations.
Figure 11-2. XTAL Oscillator External Connections
MC68HC908QY/QT Family Data Sheet, Rev. 5 92 Freescale Semiconductor
Oscillator Module Signals
11.3.4 RC Oscillator
The RC oscillator circuit is designed for use with an external resistor (REXT) to provide a clock source with a tolerance within 25% of the expected frequency. See Figure 11-3. The capacitor (C) for the RC oscillator is internal to the MCU. The REXT value must have a tolerance of 1% or less to minimize its effect on the frequency. In this configuration, the OSC2 pin can be left in the reset state as PTA4. Or, the OSC2EN bit in the port A pullup enable register can be set to enable the OSC2 output function on the pin. Enabling the OSC2 output slightly increases the external RC oscillator frequency, fRCCLK.
OSCRCOPT FROM SIM INTCLK 0 BUSCLKX4 1 SIMOSCEN EXTERNAL RC EN OSCILLATOR RCCLK /2 BUSCLKX2 TO SIM TO SIM
1 PTA4 I/O
0 MCU OSC1 PTA4/BUSCLKX4 (OSC2)
PTA4 OSC2EN
VDD REXT See Chapter 16 Electrical Specifications for component value requirements.
Figure 11-3. RC Oscillator External Connections
11.4 Oscillator Module Signals
The following paragraphs describe the signals that are inputs to and outputs from the oscillator module.
11.4.1 Crystal Amplifier Input Pin (OSC1)
The OSC1 pin is either an input to the crystal oscillator amplifier, an input to the RC oscillator circuit, or an external clock source. For the internal oscillator configuration, the OSC1 pin can assume other functions according to Table 1-3. Function Priority in Shared Pins.
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 93
Oscillator Module (OSC)
11.4.2 Crystal Amplifier Output Pin (OSC2/PTA4/BUSCLKX4)
For the XTAL oscillator device, the OSC2 pin is the crystal oscillator inverting amplifier output. For the external clock option, the OSC2 pin is dedicated to the PTA4 I/O function. The OSC2EN bit has no effect. For the internal oscillator or RC oscillator options, the OSC2 pin can assume other functions according to Table 1-3. Function Priority in Shared Pins, or the output of the oscillator clock (BUSCLKX4). Table 11-1. OSC2 Pin Function
Option XTAL oscillator External clock Internal oscillator or RC oscillator OSC2 Pin Function Inverting OSC1 PTA4 I/O Controlled by OSC2EN bit in PTAPUE register OSC2EN = 0: PTA4 I/O OSC2EN = 1: BUSCLKX4 output
11.4.3 Oscillator Enable Signal (SIMOSCEN)
The SIMOSCEN signal comes from the system integration module (SIM) and enables/disables either the XTAL oscillator circuit, the RC oscillator, or the internal oscillator.
11.4.4 XTAL Oscillator Clock (XTALCLK)
XTALCLK is the XTAL oscillator output signal. It runs at the full speed of the crystal (fXCLK) and comes directly from the crystal oscillator circuit. Figure 11-2 shows only the logical relation of XTALCLK to OSC1 and OSC2 and may not represent the actual circuitry. The duty cycle of XTALCLK is unknown and may depend on the crystal and other external factors. Also, the frequency and amplitude of XTALCLK can be unstable at start up.
11.4.5 RC Oscillator Clock (RCCLK)
RCCLK is the RC oscillator output signal. Its frequency is directly proportional to the time constant of external R and internal C. Figure 11-3 shows only the logical relation of RCCLK to OSC1 and may not represent the actual circuitry.
11.4.6 Internal Oscillator Clock (INTCLK)
INTCLK is the internal oscillator output signal. Its nominal frequency is fixed to 12.8 MHz, but it can be also trimmed using the oscillator trimming feature of the OSCTRIM register (see 11.3.1.1 Internal Oscillator Trimming).
11.4.7 Oscillator Out 2 (BUSCLKX4)
BUSCLKX4 is the same as the input clock (XTALCLK, RCCLK, or INTCLK). This signal is driven to the SIM module and is used to determine the COP cycles.
11.4.8 Oscillator Out (BUSCLKX2)
The frequency of this signal is equal to half of the BUSCLKX4, this signal is driven to the SIM for generation of the bus clocks used by the CPU and other modules on the MCU. BUSCLKX2 will be divided
MC68HC908QY/QT Family Data Sheet, Rev. 5 94 Freescale Semiconductor
Low Power Modes
again in the SIM and results in the internal bus frequency being one fourth of either the XTALCLK, RCCLK, or INTCLK frequency.
11.5 Low Power Modes
The WAIT and STOP instructions put the MCU in low-power consumption standby modes.
11.5.1 Wait Mode
The WAIT instruction has no effect on the oscillator logic. BUSCLKX2 and BUSCLKX4 continue to drive to the SIM module.
11.5.2 Stop Mode
The STOP instruction disables either the XTALCLK, the RCCLK, or INTCLK output, hence BUSCLKX2 and BUSCLKX4.
11.6 Oscillator During Break Mode
The oscillator continues to drive BUSCLKX2 and BUSCLKX4 when the device enters the break state.
11.7 CONFIG2 Options
Two CONFIG2 register options affect the operation of the oscillator module: OSCOPT1 and OSCOPT0. All CONFIG2 register bits will have a default configuration. Refer to Chapter 5 Configuration Register (CONFIG) for more information on how the CONFIG2 register is used. Table 11-2 shows how the OSCOPT bits are used to select the oscillator clock source.
.
Table 11-2. Oscillator Modes
OSCOPT1 0 0 1 1 OSCOPT0 0 1 0 1 Oscillator Modes Internal oscillator External oscillator External RC External crystal
11.8 Input/Output (I/O) Registers
The oscillator module contains these two registers: 1. Oscillator status register (OSCSTAT) 2. Oscillator trim register (OSCTRIM)
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 95
Oscillator Module (OSC)
11.8.1 Oscillator Status Register
The oscillator status register (OSCSTAT) contains the bits for switching from internal to external clock sources.
Address: $0036 Bit 7 Read: Write: Reset: R 0 R 6 R 0 = Reserved 5 R 0 4 R 0 3 R 0 = Unimplemented 2 R 0 1 ECGON 0 Bit 0 ECGST 0
Figure 11-4. Oscillator Status Register (OSCSTAT) ECGON -- External Clock Generator On Bit This read/write bit enables external clock generator, so that the switching process can be initiated. This bit is forced low during reset. This bit is ignored in monitor mode with the internal oscillator bypassed, PTM or CTM mode. 1 = External clock generator enabled 0 = External clock generator disabled ECGST -- External Clock Status Bit This read-only bit indicates whether or not an external clock source is engaged to drive the system clock. 1 = An external clock source engaged 0 = An external clock source disengaged
11.8.2 Oscillator Trim Register (OSCTRIM)
Address: $0038 Bit 7 Read: Write: Reset: TRIM7 1 6 TRIM6 0 5 TRIM5 0 4 TRIM4 0 3 TRIM3 0 2 TRIM2 0 1 TRIM1 0 Bit 0 TRIM0 0
Figure 11-5. Oscillator Trim Register (OSCTRIM) TRIM7-TRIM0 -- Internal Oscillator Trim Factor Bits These read/write bits change the size of the internal capacitor used by the internal oscillator. By measuring the period of the internal clock and adjusting this factor accordingly, the frequency of the internal clock can be fine tuned. Increasing (decreasing) this factor by one increases (decreases) the period by approximately 0.2% of the untrimmed period (the period for TRIM = $80). The trimmed frequency is guaranteed not to vary by more than 5% over the full specified range of temperature and voltage. The reset value is $80, which sets the frequency to 12.8 MHz (3.2 MHz bus speed) 25%.
MC68HC908QY/QT Family Data Sheet, Rev. 5 96 Freescale Semiconductor
Chapter 12 Input/Output Ports (PORTS)
12.1 Introduction
The MC68HC908QT1, MC68HC908QT2, and MC68HC908QT4 have five bidirectional input-output (I/O) pins and one input only pin. The MC68HC908QY1, MC68HC908QY2, and MC68HC908QY4 have thirteen bidirectional pins and one input only pin. All I/O pins are programmable as inputs or outputs. NOTE Connect any unused I/O pins to an appropriate logic level, either VDD or VSS. Although the I/O ports do not require termination for proper operation, termination reduces excess current consumption and the possibility of electrostatic damage. 8-pin devices have non-bonded pins. These pins should be configured either as outputs driving low or high, or as inputs with internal pullups enabled. Configuring these non-bonded pins in this manner will prevent any excess current consumption caused by floating inputs.
12.2 Port A
Port A is a 6-bit special function port that shares all six of its pins with the keyboard interrupt (KBI) module (see Chapter 9 Keyboard Interrupt Module (KBI)). Each port A pin also has a software configurable pullup device if the corresponding port pin is configured as an input port. NOTE PTA2 is input only. When the IRQ function is enabled in the configuration register 2 (CONFIG2), bit 2 of the port A data register (PTA) will always read a 0. In this case, the BIH and BIL instructions can be used to read the logic level on the PTA2 pin. When the IRQ function is disabled, these instructions will behave as if the PTA2 pin is a logic 1. However, reading bit 2 of PTA will read the actual logic level on the pin.
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 97
Input/Output Ports (PORTS)
12.2.1 Port A Data Register
The port A data register (PTA) contains a data latch for each of the six port A pins.
Address: $0000 Bit 7 Read: Write: Reset: Additional Functions: R = Reserved KBI5 R 6 AWUL 5 PTA5 4 PTA4 3 PTA3 2 PTA2 1 PTA1 Bit 0 PTA0
Unaffected by reset KBI4 KBI3 KBI2 KBI1 KBI0
= Unimplemented
Figure 12-1. Port A Data Register (PTA) PTA[5:0] -- Port A Data Bits These read/write bits are software programmable. Data direction of each port A pin is under the control of the corresponding bit in data direction register A. Reset has no effect on port A data. AWUL -- Auto Wakeup Latch Data Bit This is a read-only bit which has the value of the auto wakeup interrupt request latch. The wakeup request signal is generated internally (see Chapter 4 Auto Wakeup Module (AWU)). There is no PTA6 port nor any of the associated bits such as PTA6 data register, pullup enable or direction. KBI[5:0] -- Port A Keyboard Interrupts The keyboard interrupt enable bits, KBIE5-KBIE0, in the keyboard interrupt control enable register (KBIER) enable the port A pins as external interrupt pins (see Chapter 9 Keyboard Interrupt Module (KBI)).
12.2.2 Data Direction Register A
Data direction register A (DDRA) determines whether each port A pin is an input or an output. Writing a 1 to a DDRA bit enables the output buffer for the corresponding port A pin; a 0 disables the output buffer.
Address: $0004 Bit 7 Read: Write: Reset: R 0 R 6 R 0 = Reserved 5 DDRA5 0 4 DDRA4 0 3 DDRA3 0 2 0 0 1 DDRA1 0 Bit 0 DDRA0 0
= Unimplemented
Figure 12-2. Data Direction Register A (DDRA) DDRA[5:0] -- Data Direction Register A Bits These read/write bits control port A data direction. Reset clears DDRA[5:0], configuring all port A pins as inputs. 1 = Corresponding port A pin configured as output 0 = Corresponding port A pin configured as input NOTE Avoid glitches on port A pins by writing to the port A data register before changing data direction register A bits from 0 to 1.
MC68HC908QY/QT Family Data Sheet, Rev. 5 98 Freescale Semiconductor
Port A
Figure 12-3 shows the port A I/O logic.
READ DDRA ($0004) PTAPUEx WRITE DDRA ($0004) INTERNAL DATA BUS RESET WRITE PTA ($0000) PTAx PTAx DDRAx 30 k
READ PTA ($0000)
TO KEYBOARD INTERRUPT CIRCUIT
Figure 12-3. Port A I/O Circuit NOTE Figure 12-3 does not apply to PTA2 When DDRAx is a 1, reading address $0000 reads the PTAx data latch. When DDRAx is a 0, reading address $0000 reads the voltage level on the pin. The data latch can always be written, regardless of the state of its data direction bit.
12.2.3 Port A Input Pullup Enable Register
The port A input pullup enable register (PTAPUE) contains a software configurable pullup device for each if the six port A pins. Each bit is individually configurable and requires the corresponding data direction register, DDRAx, to be configured as input. Each pullup device is automatically and dynamically disabled when its corresponding DDRAx bit is configured as output.
Address: $000B Bit 7 Read: Write: Reset: OSC2EN 0 0 6 5 PTAPUE5 0 4 PTAPUE4 0 3 PTAPUE3 0 2 PTAPUE2 0 1 PTAPUE1 0 Bit 0 PTAPUE0 0
= Unimplemented
Figure 12-4. Port A Input Pullup Enable Register (PTAPUE)
OSC2EN -- Enable PTA4 on OSC2 Pin
This read/write bit configures the OSC2 pin function when internal oscillator or RC oscillator option is selected. This bit has no effect for the XTAL or external oscillator options. 1 = OSC2 pin outputs the internal or RC oscillator clock (BUSCLKX4) 0 = OSC2 pin configured for PTA4 I/O, having all the interrupt and pullup functions
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 99
Input/Output Ports (PORTS)
PTAPUE[5:0] -- Port A Input Pullup Enable Bits These read/write bits are software programmable to enable pullup devices on port A pins. 1 = Corresponding port A pin configured to have internal pull if its DDRA bit is set to 0 0 = Pullup device is disconnected on the corresponding port A pin regardless of the state of its DDRA bit Table 12-1 summarizes the operation of the port A pins. Table 12-1. Port A Pin Functions
PTAPUE Bit 1 0 X DDRA Bit 0 0 1 PTA Bit X(1) X X I/O Pin Mode Input, VDD
(2)
Accesses to DDRA Read/Write DDRA5-DDRA0 DDRA5-DDRA0 DDRA5-DDRA0
Accesses to PTA Read Pin Pin PTA5-PTA0 Write PTA5-PTA0(3) PTA5-PTA0(3) PTA5-PTA0(5)
Input, Hi-Z(4) Output
1. X = don't care 2. I/O pin pulled to VDD by internal pullup. 3. Writing affects data register, but does not affect input. 4. Hi-Z = high impedance 5. Output does not apply to PTA2
12.3 Port B
Port B is an 8-bit general purpose I/O port. Port B is only available on the MC68HC908QY1, MC68HC908QY2, and MC68HC908QY4.
12.3.1 Port B Data Register
The port B data register (PTB) contains a data latch for each of the eight port B pins.
Address: $0001 Bit 7 Read: Write: Reset: PTB7 6 PTB6 5 PTB5 4 PTB4 3 PTB3 2 PTB2 1 PTB1 Bit 0 PTB0
Unaffected by reset
Figure 12-5. Port B Data Register (PTB) PTB[7:0] -- Port B Data Bits These read/write bits are software programmable. Data direction of each port B pin is under the control of the corresponding bit in data direction register B. Reset has no effect on port B data.
MC68HC908QY/QT Family Data Sheet, Rev. 5 100 Freescale Semiconductor
Port B
12.3.2 Data Direction Register B
Data direction register B (DDRB) determines whether each port B pin is an input or an output. Writing a 1 to a DDRB bit enables the output buffer for the corresponding port B pin; a 0 disables the output buffer.
Address: $0005 Bit 7 Read: Write: Reset: DDRB7 0 6 DDRB6 0 5 DDRB5 0 4 DDRB4 0 3 DDRB3 0 2 DDRB2 0 1 DDRB1 0 Bit 0 DDRB0 0
Figure 12-6. Data Direction Register B (DDRB) DDRB[7:0] -- Data Direction Register B Bits These read/write bits control port B data direction. Reset clears DDRB[7:0], configuring all port B pins as inputs. 1 = Corresponding port B pin configured as output 0 = Corresponding port B pin configured as input NOTE Avoid glitches on port B pins by writing to the port B data register before changing data direction register B bits from 0 to 1. Figure 12-7 shows the port B I/O logic.
READ DDRB ($0005) PTBPUEx WRITE DDRB ($0005) INTERNAL DATA BUS RESET WRITE PTB ($0001) PTBx PTBx DDRBx 30 k
READ PTB ($0001)
Figure 12-7. Port B I/O Circuit When DDRBx is a 1, reading address $0001 reads the PTBx data latch. When DDRBx is a 0, reading address $0001 reads the voltage level on the pin. The data latch can always be written, regardless of the state of its data direction bit. Table 12-2 summarizes the operation of the port B pins. Table 12-2. Port B Pin Functions
DDRB Bit 0 1 PTB Bit X(1) X I/O Pin Mode Input, Hi-Z(2) Output Accesses to DDRB Read/Write DDRB7-DDRB0 DDRB7-DDRB0 Accesses to PTB Read Pin Pin Write PTB7-PTB0(3) PTB7-PTB0
1. X = don't care 2. Hi-Z = high impedance 3. Writing affects data register, but does not affect the input. MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 101
Input/Output Ports (PORTS)
12.3.3 Port B Input Pullup Enable Register
The port B input pullup enable register (PTBPUE) contains a software configurable pullup device for each of the eight port B pins. Each bit is individually configurable and requires the corresponding data direction register, DDRBx, be configured as input. Each pullup device is automatically and dynamically disabled when its corresponding DDRBx bit is configured as output.
Address: $000C Bit 7 Read: Write: Reset: PTBPUE7 0 6 PTBPUE6 0 5 PTBPUE5 0 4 PTBPUE4 0 3 PTBPUE3 0 2 PTBPUE2 0 1 PTBPUE2 0 Bit 0 PTBPUE0 0
Figure 12-8. Port B Input Pullup Enable Register (PTBPUE) PTBPUE[7:0] -- Port B Input Pullup Enable Bits These read/write bits are software programmable to enable pullup devices on port B pins 1 = Corresponding port B pin configured to have internal pull if its DDRB bit is set to 0 0 = Pullup device is disconnected on the corresponding port B pin regardless of the state of its DDRB bit. Table 12-3 summarizes the operation of the port B pins. Table 12-3. Port B Pin Functions
PTBPUE Bit 1 0 X 1. 2. 3. 4. DDRB Bit 0 0 1 PTB Bit X(1) X X I/O Pin Mode Input, VDD(2) Input, Hi-Z(4) Output Accesses to DDRB Read/Write DDRB7-DDRB0 DDRB7-DDRB0 DDRB7-DDRB0 Accesses to PTB Read Pin Pin PTB7-PTB0 Write PTB7-PTB0(3) PTB7-PTB0(3) PTB7-PTB0
X = don't care I/O pin pulled to VDD by internal pullup. Writing affects data register, but does not affect input. Hi-Z = high impedance
MC68HC908QY/QT Family Data Sheet, Rev. 5 102 Freescale Semiconductor
Chapter 13 System Integration Module (SIM)
13.1 Introduction
This section describes the system integration module (SIM), which supports up to 24 external and/or internal interrupts. Together with the central processor unit (CPU), the SIM controls all microcontroller unit (MCU) activities. A block diagram of the SIM is shown in Figure 13-1. The SIM is a system state controller that coordinates CPU and exception timing. The SIM is responsible for: * Bus clock generation and control for CPU and peripherals - Stop/wait/reset/break entry and recovery - Internal clock control * Master reset control, including power-on reset (POR) and computer operating properly (COP) timeout * Interrupt control: - Acknowledge timing - Arbitration control timing - Vector address generation * CPU enable/disable timing Table 13-1. Signal Name Conventions
Signal Name BUSCLKX4 BUSCLKX2 Address bus Data bus PORRST IRST R/W Description Buffered clock from the internal, RC or XTAL oscillator circuit. The BUSCLKX4 frequency divided by two. This signal is again divided by two in the SIM to generate the internal bus clocks (bus clock = BUSCLKX4 / 4). Internal address bus Internal data bus Signal from the power-on reset module to the SIM Internal reset signal Read/write signal
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 103
System Integration Module (SIM)
MODULE STOP MODULE WAIT STOP/WAIT CONTROL CPU STOP (FROM CPU) CPU WAIT (FROM CPU) SIMOSCEN (TO OSCILLATOR) SIM COUNTER COP CLOCK
BUSCLKX4 (FROM OSCILLATOR) BUSCLKX2 (FROM OSCILLATOR) /2 VDD CLOCK CONTROL CLOCK GENERATORS INTERNAL CLOCKS
INTERNAL PULL-UP
RESET PIN LOGIC
POR CONTROL RESET PIN CONTROL SIM RESET STATUS REGISTER MASTER RESET CONTROL
ILLEGAL OPCODE (FROM CPU) ILLEGAL ADDRESS (FROM ADDRESS MAP DECODERS) COP TIMEOUT (FROM COP MODULE) LVI RESET (FROM LVI MODULE) FORCED MON MODE ENTRY (FROM MENRST MODULE)
RESET
INTERRUPT CONTROL AND PRIORITY DECODE
INTERRUPT SOURCES CPU INTERFACE
Figure 13-1. SIM Block Diagram
13.2 RST and IRQ Pins Initialization
RST and IRQ pins come out of reset as PTA3 and PTA2 respectively. RST and IRQ functions can be activated by programing CONFIG2 accordingly. Refer to Chapter 5 Configuration Register (CONFIG).
13.3 SIM Bus Clock Control and Generation
The bus clock generator provides system clock signals for the CPU and peripherals on the MCU. The system clocks are generated from an incoming clock, BUSCLKX2, as shown in Figure 13-2.
MC68HC908QY/QT Family Data Sheet, Rev. 5 104 Freescale Semiconductor
Reset and System Initialization
FROM OSCILLATOR FROM OSCILLATOR
BUSCLKX4 BUSCLKX2
SIM COUNTER
/2
BUS CLOCK GENERATORS
SIM
Figure 13-2. SIM Clock Signals
13.3.1 Bus Timing
In user mode, the internal bus frequency is the oscillator frequency (BUSCLKX4) divided by four.
13.3.2 Clock Start-Up from POR
When the power-on reset module generates a reset, the clocks to the CPU and peripherals are inactive and held in an inactive phase until after the 4096 BUSCLKX4 cycle POR time out has completed. The IBUS clocks start upon completion of the time out.
13.3.3 Clocks in Stop Mode and Wait Mode
Upon exit from stop mode by an interrupt or reset, the SIM allows BUSCLKX4 to clock the SIM counter. The CPU and peripheral clocks do not become active until after the stop delay time out. This time out is selectable as 4096 or 32 BUSCLKX4 cycles. See 13.7.2 Stop Mode. In wait mode, the CPU clocks are inactive. The SIM also produces two sets of clocks for other modules. Refer to the wait mode subsection of each module to see if the module is active or inactive in wait mode. Some modules can be programmed to be active in wait mode.
13.4 Reset and System Initialization
The MCU has these reset sources: * Power-on reset module (POR) * External reset pin (RST) * Computer operating properly module (COP) * Low-voltage inhibit module (LVI) * Illegal opcode * Illegal address All of these resets produce the vector $FFFE-FFFF ($FEFE-FEFF in monitor mode) and assert the internal reset signal (IRST). IRST causes all registers to be returned to their default values and all modules to be returned to their reset states. An internal reset clears the SIM counter (see 13.5 SIM Counter), but an external reset does not. Each of the resets sets a corresponding bit in the SIM reset status register (SRSR). See 13.8 SIM Registers.
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 105
System Integration Module (SIM)
13.4.1 External Pin Reset
The RST pin circuits include an internal pullup device. Pulling the asynchronous RST pin low halts all processing. The PIN bit of the SIM reset status register (SRSR) is set as long as RST is held low for at least the minimum tRL time. Figure 13-3 shows the relative timing. The RST pin function is only available if the RSTEN bit is set in the CONFIG2 register.
BUSCLKX2 RST ADDRESS BUS PC VECT H VECT L
Figure 13-3. External Reset Timing
13.4.2 Active Resets from Internal Sources
The RST pin is initially setup as a general-purpose input after a POR. Setting the RSTEN bit in the CONFIG2 register enables the pin for the reset function. This section assumes the RSTEN bit is set when describing activity on the RST pin. NOTE For POR and LVI resets, the SIM cycles through 4096 BUSCLKX4 cycles during which the SIM forces the RST pin low. The internal reset signal then follows the sequence from the falling edge of RST shown in Figure 13-4. The COP reset is asynchronous to the bus clock. The active reset feature allows the part to issue a reset to peripherals and other chips within a system built around the MCU. All internal reset sources actively pull the RST pin low for 32 BUSCLKX4 cycles to allow resetting of external peripherals. The internal reset signal IRST continues to be asserted for an additional 32 cycles (see Figure 13-4). An internal reset can be caused by an illegal address, illegal opcode, COP time out, LVI, or POR (see Figure 13-5).
IRST
RST
RST PULLED LOW BY MCU 32 CYCLES 32 CYCLES
BUSCLKX4 ADDRESS BUS
VECTOR HIGH
Figure 13-4. Internal Reset Timing
MC68HC908QY/QT Family Data Sheet, Rev. 5 106 Freescale Semiconductor
Reset and System Initialization
ILLEGAL ADDRESS RST ILLEGAL OPCODE RST COPRST POR LVI INTERNAL RESET
Figure 13-5. Sources of Internal Reset Table 13-2. Reset Recovery Timing
Reset Recovery Type POR/LVI All others Actual Number of Cycles 4163 (4096 + 64 + 3) 67 (64 + 3)
13.4.2.1 Power-On Reset When power is first applied to the MCU, the power-on reset module (POR) generates a pulse to indicate that power on has occurred. The SIM counter counts out 4096 BUSCLKX4 cycles. Sixty-four BUSCLKX4 cycles later, the CPU and memories are released from reset to allow the reset vector sequence to occur. At power on, the following events occur: * A POR pulse is generated. * The internal reset signal is asserted. * The SIM enables the oscillator to drive BUSCLKX4. * Internal clocks to the CPU and modules are held inactive for 4096 BUSCLKX4 cycles to allow stabilization of the oscillator. * The POR bit of the SIM reset status register (SRSR) is set See Figure 13-6.
OSC1
PORRST 4096 CYCLES BUSCLKX4 32 CYCLES 32 CYCLES
BUSCLKX2
RST ADDRESS BUS $FFFE $FFFF
Figure 13-6. POR Recovery
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 107
System Integration Module (SIM)
13.4.2.2 Computer Operating Properly (COP) Reset An input to the SIM is reserved for the COP reset signal. The overflow of the COP counter causes an internal reset and sets the COP bit in the SIM reset status register (SRSR). The SIM actively pulls down the RST pin for all internal reset sources. To prevent a COP module time out, write any value to location $FFFF. Writing to location $FFFF clears the COP counter and stages 12-5 of the SIM counter. The SIM counter output, which occurs at least every 4080 BUSCLKX4 cycles, drives the COP counter. The COP should be serviced as soon as possible out of reset to guarantee the maximum amount of time before the first time out. The COP module is disabled during a break interrupt with monitor mode when BDCOP bit is set in break auxiliary register (BRKAR). 13.4.2.3 Illegal Opcode Reset The SIM decodes signals from the CPU to detect illegal instructions. An illegal instruction sets the ILOP bit in the SIM reset status register (SRSR) and causes a reset. If the stop enable bit, STOP, in the mask option register is 0, the SIM treats the STOP instruction as an illegal opcode and causes an illegal opcode reset. The SIM actively pulls down the RST pin for all internal reset sources. 13.4.2.4 Illegal Address Reset An opcode fetch from an unmapped address generates an illegal address reset. The SIM verifies that the CPU is fetching an opcode prior to asserting the ILAD bit in the SIM reset status register (SRSR) and resetting the MCU. A data fetch from an unmapped address does not generate a reset. The SIM actively pulls down the RST pin for all internal reset sources. See Figure 2-1. Memory Map for memory ranges. 13.4.2.5 Low-Voltage Inhibit (LVI) Reset The LVI asserts its output to the SIM when the VDD voltage falls to the LVI trip voltage VTRIPF. The LVI bit in the SIM reset status register (SRSR) is set, and the external reset pin (RST) is held low while the SIM counter counts out 4096 BUSCLKX4 cycles after VDD rises above VTRIPR. Sixty-four BUSCLKX4 cycles later, the CPU and memories are released from reset to allow the reset vector sequence to occur. The SIM actively pulls down the (RST) pin for all internal reset sources.
13.5 SIM Counter
The SIM counter is used by the power-on reset module (POR) and in stop mode recovery to allow the oscillator time to stabilize before enabling the internal bus (IBUS) clocks. The SIM counter also serves as a prescaler for the computer operating properly module (COP). The SIM counter uses 12 stages for counting, followed by a 13th stage that triggers a reset of SIM counters and supplies the clock for the COP module. The SIM counter is clocked by the falling edge of BUSCLKX4.
13.5.1 SIM Counter During Power-On Reset
The power-on reset module (POR) detects power applied to the MCU. At power-on, the POR circuit asserts the signal PORRST. Once the SIM is initialized, it enables the oscillator to drive the bus clock state machine.
MC68HC908QY/QT Family Data Sheet, Rev. 5 108 Freescale Semiconductor
Exception Control
13.5.2 SIM Counter During Stop Mode Recovery
The SIM counter also is used for stop mode recovery. The STOP instruction clears the SIM counter. After an interrupt, break, or reset, the SIM senses the state of the short stop recovery bit, SSREC, in the configuration register 1 (CONFIG1). If the SSREC bit is a 1, then the stop recovery is reduced from the normal delay of 4096 BUSCLKX4 cycles down to 32 BUSCLKX4 cycles. This is ideal for applications using canned oscillators that do not require long start-up times from stop mode. External crystal applications should use the full stop recovery time, that is, with SSREC cleared in the configuration register 1 (CONFIG1).
13.5.3 SIM Counter and Reset States
External reset has no effect on the SIM counter (see 13.7.2 Stop Mode for details.) The SIM counter is free-running after all reset states. See 13.4.2 Active Resets from Internal Sources for counter control and internal reset recovery sequences.
13.6 Exception Control
Normal sequential program execution can be changed in three different ways: 1. Interrupts a. Maskable hardware CPU interrupts b. Non-maskable software interrupt instruction (SWI) 2. Reset 3. Break interrupts
13.6.1 Interrupts
An interrupt temporarily changes the sequence of program execution to respond to a particular event. Figure 13-7 flow charts the handling of system interrupts. Interrupts are latched, and arbitration is performed in the SIM at the start of interrupt processing. The arbitration result is a constant that the CPU uses to determine which vector to fetch. Once an interrupt is latched by the SIM, no other interrupt can take precedence, regardless of priority, until the latched interrupt is serviced (or the I bit is cleared). At the beginning of an interrupt, the CPU saves the CPU register contents on the stack and sets the interrupt mask (I bit) to prevent additional interrupts. At the end of an interrupt, the RTI instruction recovers the CPU register contents from the stack so that normal processing can resume. Figure 13-8 shows interrupt entry timing. Figure 13-9 shows interrupt recovery timing.
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 109
System Integration Module (SIM)
FROM RESET
BREAK INTERRUPT? I BIT SET? NO
YES
YES
I BIT SET?
NO
IRQ INTERRUPT? NO
YES
TIMER INTERRUPT? NO
YES
STACK CPU REGISTERS SET I BIT LOAD PC WITH INTERRUPT VECTOR
(AS MANY INTERRUPTS AS EXIST ON CHIP)
FETCH NEXT INSTRUCTION
SWI INSTRUCTION? NO
YES
RTI INSTRUCTION? NO
YES
UNSTACK CPU REGISTERS
EXECUTE INSTRUCTION
Figure 13-7. Interrupt Processing
MC68HC908QY/QT Family Data Sheet, Rev. 5 110 Freescale Semiconductor
Exception Control
MODULE INTERRUPT I BIT
ADDRESS BUS
DUMMY
SP
SP - 1
SP - 2
SP - 3
SP - 4
VECT H
VECT L
START ADDR
DATA BUS
DUMMY
PC - 1[7:0] PC - 1[15:8]
X
A
CCR
V DATA H
V DATA L
OPCODE
R/W
Figure 13-8. Interrupt Entry
MODULE INTERRUPT I BIT
ADDRESS BUS
SP - 4
SP - 3
SP - 2
SP - 1
SP
PC
PC + 1
DATA BUS
CCR
A
X
PC - 1[7:0] PC - 1[15:8] OPCODE
OPERAND
R/W
Figure 13-9. Interrupt Recovery 13.6.1.1 Hardware Interrupts A hardware interrupt does not stop the current instruction. Processing of a hardware interrupt begins after completion of the current instruction. When the current instruction is complete, the SIM checks all pending hardware interrupts. If interrupts are not masked (I bit clear in the condition code register), and if the corresponding interrupt enable bit is set, the SIM proceeds with interrupt processing; otherwise, the next instruction is fetched and executed. If more than one interrupt is pending at the end of an instruction execution, the highest priority interrupt is serviced first. Figure 13-10 demonstrates what happens when two interrupts are pending. If an interrupt is pending upon exit from the original interrupt service routine, the pending interrupt is serviced before the LDA instruction is executed. The LDA opcode is prefetched by both the INT1 and INT2 return-from-interrupt (RTI) instructions. However, in the case of the INT1 RTI prefetch, this is a redundant operation. NOTE To maintain compatibility with the M6805 Family, the H register is not pushed on the stack during interrupt entry. If the interrupt service routine modifies the H register or uses the indexed addressing mode, software should save the H register and then restore it prior to exiting the routine.
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 111
System Integration Module (SIM)
CLI LDA #$FF BACKGROUND ROUTINE
INT1
PSHH INT1 INTERRUPT SERVICE ROUTINE PULH RTI
INT2
PSHH INT2 INTERRUPT SERVICE ROUTINE PULH RTI
Figure 13-10. Interrupt Recognition Example 13.6.1.2 SWI Instruction The SWI instruction is a non-maskable instruction that causes an interrupt regardless of the state of the interrupt mask (I bit) in the condition code register. NOTE A software interrupt pushes PC onto the stack. A software interrupt does not push PC - 1, as a hardware interrupt does.
13.6.2 Interrupt Status Registers
The flags in the interrupt status registers identify maskable interrupt sources. Table 13-3 summarizes the interrupt sources and the interrupt status register flags that they set. The interrupt status registers can be useful for debugging. Table 13-3. Interrupt Sources
Priority Highest Reset SWI instruction IRQ pin Timer channel 0 interrupt Timer channel 1 interrupt Timer overflow interrupt Keyboard interrupt Lowest ADC conversion complete interrupt Source Flag -- -- IRQF CH0F CH1F TOF KEYF COCO Mask(1) -- -- IMASK CH0IE CH1IE TOIE IMASKK AIEN INT Register Flag -- -- IF1 IF3 IF4 IF5 IF14 IF15 Vector Address $FFFE-$FFFF $FFFC-$FFFD $FFFA-$FFFB $FFF6-$FFF7 $FFF4-$FFF5 $FFF2-$FFF3 $FFE0-$FFE1 $FFDE-$FFDF
1. The I bit in the condition code register is a global mask for all interrupt sources except the SWI instruction.
MC68HC908QY/QT Family Data Sheet, Rev. 5 112 Freescale Semiconductor
Exception Control
13.6.2.1 Interrupt Status Register 1
Address: $FE04 Bit 7 Read: Write: Reset: 0 R 0 R 6 IF5 R 0 = Reserved 5 IF4 R 0 4 IF3 R 0 3 0 R 0 2 IF1 R 0 1 0 R 0 Bit 0 0 R 0
Figure 13-11. Interrupt Status Register 1 (INT1) IF1 and IF3-IF5 -- Interrupt Flags These flags indicate the presence of interrupt requests from the sources shown in Table 13-3. 1 = Interrupt request present 0 = No interrupt request present Bit 0, 1, 3, and 7 -- Always read 0 13.6.2.2 Interrupt Status Register 2
Address: $FE05 Bit 7 Read: Write: Reset: IF14 R 0 R 6 0 R 0 = Reserved 5 0 R 0 4 0 R 0 3 0 R 0 2 0 R 0 1 0 R 0 Bit 0 0 R 0
Figure 13-12. Interrupt Status Register 2 (INT2) IF14 -- Interrupt Flags This flag indicates the presence of interrupt requests from the sources shown in Table 13-3. 1 = Interrupt request present 0 = No interrupt request present Bit 0-6 -- Always read 0 13.6.2.3 Interrupt Status Register 3
Address: $FE06 Bit 7 Read: Write: Reset: 0 R 0 R 6 0 R 0 = Reserved 5 0 R 0 4 0 R 0 3 0 R 0 2 0 R 0 1 0 R 0 Bit 0 IF15 R 0
Figure 13-13. Interrupt Status Register 3 (INT3) IF15 -- Interrupt Flags These flags indicate the presence of interrupt requests from the sources shown in Table 13-3. 1 = Interrupt request present 0 = No interrupt request present Bit 1-7 -- Always read 0
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 113
System Integration Module (SIM)
13.6.3 Reset
All reset sources always have equal and highest priority and cannot be arbitrated.
13.6.4 Break Interrupts
The break module can stop normal program flow at a software programmable break point by asserting its break interrupt output. (See Chapter 15 Development Support.) The SIM puts the CPU into the break state by forcing it to the SWI vector location. Refer to the break interrupt subsection of each module to see how each module is affected by the break state.
13.6.5 Status Flag Protection in Break Mode
The SIM controls whether status flags contained in other modules can be cleared during break mode. The user can select whether flags are protected from being cleared by properly initializing the break clear flag enable bit (BCFE) in the break flag control register (BFCR). Protecting flags in break mode ensures that set flags will not be cleared while in break mode. This protection allows registers to be freely read and written during break mode without losing status flag information. Setting the BCFE bit enables the clearing mechanisms. Once cleared in break mode, a flag remains cleared even when break mode is exited. Status flags with a two-step clearing mechanism -- for example, a read of one register followed by the read or write of another -- are protected, even when the first step is accomplished prior to entering break mode. Upon leaving break mode, execution of the second step will clear the flag as normal.
13.7 Low-Power Modes
Executing the WAIT or STOP instruction puts the MCU in a low power- consumption mode for standby situations. The SIM holds the CPU in a non-clocked state. The operation of each of these modes is described below. Both STOP and WAIT clear the interrupt mask (I) in the condition code register, allowing interrupts to occur.
13.7.1 Wait Mode
In wait mode, the CPU clocks are inactive while the peripheral clocks continue to run. Figure 13-14 shows the timing for wait mode entry.
ADDRESS BUS WAIT ADDR WAIT ADDR + 1 SAME SAME
DATA BUS
PREVIOUS DATA
NEXT OPCODE
SAME
SAME
R/W NOTE: Previous data can be operand data or the WAIT opcode, depending on the last instruction.
Figure 13-14. Wait Mode Entry Timing
MC68HC908QY/QT Family Data Sheet, Rev. 5 114 Freescale Semiconductor
Low-Power Modes
A module that is active during wait mode can wake up the CPU with an interrupt if the interrupt is enabled. Stacking for the interrupt begins one cycle after the WAIT instruction during which the interrupt occurred. In wait mode, the CPU clocks are inactive. Refer to the wait mode subsection of each module to see if the module is active or inactive in wait mode. Some modules can be programmed to be active in wait mode. Wait mode can also be exited by a reset (or break in emulation mode). A break interrupt during wait mode sets the SIM break stop/wait bit, SBSW, in the break status register (BSR). If the COP disable bit, COPD, in the configuration register is 0, then the computer operating properly module (COP) is enabled and remains active in wait mode. Figure 13-15 and Figure 13-16 show the timing for wait recovery.
ADDRESS BUS $6E0B $6E0C $00FF $00FE $00FD $00FC
DATA BUS
$A6
$A6
$A6
$01
$0B
$6E
EXITSTOPWAIT NOTE: EXITSTOPWAIT = RST pin OR CPU interrupt OR break interrupt
Figure 13-15. Wait Recovery from Interrupt
32 CYCLES ADDRESS BUS $6E0B 32 CYCLES RSTVCT H RSTVCT L
DATA BUS
$A6
$A6
$A6
RST
BUSCLKX4
Figure 13-16. Wait Recovery from Internal Reset
13.7.2 Stop Mode
In stop mode, the SIM counter is reset and the system clocks are disabled. An interrupt request from a module can cause an exit from stop mode. Stacking for interrupts begins after the selected stop recovery time has elapsed. Reset or break also causes an exit from stop mode. The SIM disables the oscillator signals (BUSCLKX2 and BUSCLKX4) in stop mode, stopping the CPU and peripherals. Stop recovery time is selectable using the SSREC bit in the configuration register 1 (CONFIG1). If SSREC is set, stop recovery is reduced from the normal delay of 4096 BUSCLKX4 cycles down to 32. This is ideal for the internal oscillator, RC oscillator, and external oscillator options which do not require long start-up times from stop mode. NOTE External crystal applications should use the full stop recovery time by clearing the SSREC bit.
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 115
System Integration Module (SIM)
The SIM counter is held in reset from the execution of the STOP instruction until the beginning of stop recovery. It is then used to time the recovery period. Figure 13-17 shows stop mode entry timing and Figure 13-18 shows the stop mode recovery time from interrupt or break. NOTE To minimize stop current, all pins configured as inputs should be driven to a logic 1 or logic 0.
CPUSTOP
ADDRESS BUS
STOP ADDR
STOP ADDR + 1
SAME
SAME
DATA BUS
PREVIOUS DATA
NEXT OPCODE
SAME
SAME
R/W NOTE: Previous data can be operand data or the STOP opcode, depending on the last instruction.
Figure 13-17. Stop Mode Entry Timing
STOP RECOVERY PERIOD BUSCLKX4
INTERRUPT
ADDRESS BUS
STOP +1
STOP + 2
STOP + 2
SP
SP - 1
SP - 2
SP - 3
Figure 13-18. Stop Mode Recovery from Interrupt
13.8 SIM Registers
The SIM has three memory mapped registers. Table 13-4 shows the mapping of these registers. Table 13-4. SIM Registers
Address $FE00 $FE01 $FE03 Register BSR SRSR BFCR Access Mode User User User
MC68HC908QY/QT Family Data Sheet, Rev. 5 116 Freescale Semiconductor
SIM Registers
13.8.1 SIM Reset Status Register
The SRSR register contains flags that show the source of the last reset. The status register will automatically clear after reading SRSR. A power-on reset sets the POR bit and clears all other bits in the register. All other reset sources set the individual flag bits but do not clear the register. More than one reset source can be flagged at any time depending on the conditions at the time of the internal or external reset. For example, the POR and LVI bit can both be set if the power supply has a slow rise time.
Address: $FE01 Bit 7 Read: Write: POR: 1 0 = Unimplemented 0 0 0 0 0 0 POR 6 PIN 5 COP 4 ILOP 3 ILAD 2 MODRST 1 LVI Bit 0 0
Figure 13-19. SIM Reset Status Register (SRSR) POR -- Power-On Reset Bit 1 = Last reset caused by POR circuit 0 = Read of SRSR PIN -- External Reset Bit 1 = Last reset caused by external reset pin (RST) 0 = POR or read of SRSR COP -- Computer Operating Properly Reset Bit 1 = Last reset caused by COP counter 0 = POR or read of SRSR ILOP -- Illegal Opcode Reset Bit 1 = Last reset caused by an illegal opcode 0 = POR or read of SRSR ILAD -- Illegal Address Reset Bit (illegal attempt to fetch an opcode from an unimplemented address) 1 = Last reset caused by an opcode fetch from an illegal address 0 = POR or read of SRSR MODRST -- Monitor Mode Entry Module Reset Bit 1 = Last reset caused by monitor mode entry when vector locations $FFFE and $FFFF are $FF after POR while IRQ VTST 0 = POR or read of SRSR LVI -- Low Voltage Inhibit Reset Bit 1 = Last reset caused by LVI circuit 0 = POR or read of SRSR
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 117
System Integration Module (SIM)
13.8.2 Break Flag Control Register
The break control register (BFCR) contains a bit that enables software to clear status bits while the MCU is in a break state.
Address: $FE03 Bit 7 Read: Write: Reset: BCFE 0 R = Reserved 6 R 5 R 4 R 3 R 2 R 1 R Bit 0 R
Figure 13-20. Break Flag Control Register (BFCR) BCFE -- Break Clear Flag Enable Bit This read/write bit enables software to clear status bits by accessing status registers while the MCU is in a break state. To clear status bits during the break state, the BCFE bit must be set. 1 = Status bits clearable during break 0 = Status bits not clearable during break
MC68HC908QY/QT Family Data Sheet, Rev. 5 118 Freescale Semiconductor
Chapter 14 Timer Interface Module (TIM)
14.1 Introduction
This section describes the timer interface module (TIM). The TIM is a two-channel timer that provides a timing reference with input capture, output compare, and pulse-width-modulation functions. Figure 14-2 is a block diagram of the TIM.
14.2 Features
Features of the TIM include the following: * Two input capture/output compare channels - Rising-edge, falling-edge, or any-edge input capture trigger - Set, clear, or toggle output compare action * Buffered and unbuffered pulse width modulation (PWM) signal generation * Programmable TIM clock input - 7-frequency internal bus clock prescaler selection - External TIM clock input * Free-running or modulo up-count operation * Toggle any channel pin on overflow * TIM counter stop and reset bits
14.3 Pin Name Conventions
The TIM shares two input/output (I/O) pins with two port A I/O pins. The full names of the TIM I/O pins are listed in Table 14-1. The generic pin name appear in the text that follows. Table 14-1. Pin Name Conventions
TIM Generic Pin Names: Full TIM Pin Names: TCH0 PTA0/TCH0 TCH1 PTA1/TCH1 TCLK PTA2/TCLK
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 119
Timer Interface Module (TIM)
PTA0/AD0/TCH0/KBI0 PTA1/AD1/TCH1/KBI1 DDRA PTA PTA2/IRQ/KBI2/TCLK PTA3/RST/KBI3 PTA4/OSC2/AD2/KBI4 PTA5/OSC1/AD3/KBI5 M68HC08 CPU PTB0 PTB1 PTB2 PTB3 PTB4 PTB5 PTB6 PTB7 CLOCK GENERATOR (OSCILLATOR)
SYSTEM INTEGRATION MODULE SINGLE INTERRUPT MODULE BREAK MODULE POWER-ON RESET MODULE MC68HC908QY4 AND MC68HC908QT4 4096 BYTES MC68HC908QY2, MC68HC908QY1, MC68HC908QT2, AND MC68HC908QT1: 1536 BYTES USER FLASH KEYBOARD INTERRUPT MODULE 16-BIT TIMER MODULE COP MODULE VDD
8-BIT ADC
128 BYTES RAM
POWER SUPPLY VSS
DDRB
PTB
MONITOR ROM
RST, IRQ: Pins have internal (about 30K Ohms) pull up PTA[0:5]: High current sink and source capability PTA[0:5]: Pins have programmable keyboard interrupt and pull up PTB[0:7]: Not available on 8-pin devices - MC68HC908QT1, MC68HC908QT2, and MC68HC908QT4 (see note in 12.1 Introduction) ADC: Not available on the MC68HC908QY1 and MC68HC908QT1
Figure 14-1. Block Diagram Highlighting TIM Block and Pins
MC68HC908QY/QT Family Data Sheet, Rev. 5 120 Freescale Semiconductor
Functional Description
14.4 Functional Description
Figure 14-2 shows the structure of the TIM. The central component of the TIM is the 16-bit TIM counter that can operate as a free-running counter or a modulo up-counter. The TIM counter provides the timing reference for the input capture and output compare functions. The TIM counter modulo registers, TMODH:TMODL, control the modulo value of the TIM counter. Software can read the TIM counter value at any time without affecting the counting sequence. The two TIM channels are programmable independently as input capture or output compare channels.
PTA2/IRQ/KBI2/TCLK PRESCALER SELECT INTERNAL BUS CLOCK TSTOP TRST 16-BIT COUNTER 16-BIT COMPARATOR TMODH:TMODL TOV0 CHANNEL 0 16-BIT COMPARATOR TCH0H:TCH0L 16-BIT LATCH MS0A MS0B TOV1 INTERNAL BUS CHANNEL 1 16-BIT COMPARATOR TCH1H:TCH1L 16-BIT LATCH MS1A CH1IE CH1F INTERRUPT LOGIC ELS1B ELS1A CH1MAX PORT LOGIC TCH1 CH0IE CH0F INTERRUPT LOGIC ELS0B ELS0A CH0MAX PORT LOGIC TCH0 PRESCALER
PS2
PS1
PS0
TOF TOIE
INTERRUPT LOGIC
Figure 14-2. TIM Block Diagram
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 121
Timer Interface Module (TIM)
14.4.1 TIM Counter Prescaler
The TIM clock source is one of the seven prescaler outputs or the TIM clock pin, TCLK. The prescaler generates seven clock rates from the internal bus clock. The prescaler select bits, PS[2:0], in the TIM status and control register (TSC) select the TIM clock source.
14.4.2 Input Capture
With the input capture function, the TIM can capture the time at which an external event occurs. When an active edge occurs on the pin of an input capture channel, the TIM latches the contents of the TIM counter into the TIM channel registers, TCHxH:TCHxL. The polarity of the active edge is programmable. Input captures can generate TIM central processor unit (CPU) interrupt requests.
14.4.3 Output Compare
With the output compare function, the TIM can generate a periodic pulse with a programmable polarity, duration, and frequency. When the counter reaches the value in the registers of an output compare channel, the TIM can set, clear, or toggle the channel pin. Output compares can generate TIM CPU interrupt requests. 14.4.3.1 Unbuffered Output Compare Any output compare channel can generate unbuffered output compare pulses as described in 14.4.3 Output Compare. The pulses are unbuffered because changing the output compare value requires writing the new value over the old value currently in the TIM channel registers. An unsynchronized write to the TIM channel registers to change an output compare value could cause incorrect operation for up to two counter overflow periods. For example, writing a new value before the counter reaches the old value but after the counter reaches the new value prevents any compare during that counter overflow period. Also, using a TIM overflow interrupt routine to write a new, smaller output compare value may cause the compare to be missed. The TIM may pass the new value before it is written. Use the following methods to synchronize unbuffered changes in the output compare value on channel x: * When changing to a smaller value, enable channel x output compare interrupts and write the new value in the output compare interrupt routine. The output compare interrupt occurs at the end of the current output compare pulse. The interrupt routine has until the end of the counter overflow period to write the new value. * When changing to a larger output compare value, enable TIM overflow interrupts and write the new value in the TIM overflow interrupt routine. The TIM overflow interrupt occurs at the end of the current counter overflow period. Writing a larger value in an output compare interrupt routine (at the end of the current pulse) could cause two output compares to occur in the same counter overflow period. 14.4.3.2 Buffered Output Compare Channels 0 and 1 can be linked to form a buffered output compare channel whose output appears on the TCH0 pin. The TIM channel registers of the linked pair alternately control the output. Setting the MS0B bit in TIM channel 0 status and control register (TSC0) links channel 0 and channel 1. The output compare value in the TIM channel 0 registers initially controls the output on the TCH0 pin. Writing to the TIM channel 1 registers enables the TIM channel 1 registers to synchronously control the output after the TIM overflows. At each subsequent overflow, the TIM channel registers (0 or 1) that
MC68HC908QY/QT Family Data Sheet, Rev. 5 122 Freescale Semiconductor
Functional Description
control the output are the ones written to last. TSC0 controls and monitors the buffered output compare function, and TIM channel 1 status and control register (TSC1) is unused. While the MS0B bit is set, the channel 1 pin, TCH1, is available as a general-purpose I/O pin. NOTE In buffered output compare operation, do not write new output compare values to the currently active channel registers. User software should track the currently active channel to prevent writing a new value to the active channel. Writing to the active channel registers is the same as generating unbuffered output compares.
14.4.4 Pulse Width Modulation (PWM)
By using the toggle-on-overflow feature with an output compare channel, the TIM can generate a PWM signal. The value in the TIM counter modulo registers determines the period of the PWM signal. The channel pin toggles when the counter reaches the value in the TIM counter modulo registers. The time between overflows is the period of the PWM signal As Figure 14-3 shows, the output compare value in the TIM channel registers determines the pulse width of the PWM signal. The time between overflow and output compare is the pulse width. Program the TIM to clear the channel pin on output compare if the state of the PWM pulse is logic 1 (ELSxA = 0). Program the TIM to set the pin if the state of the PWM pulse is logic 0 (ELSxA = 1). The value in the TIM counter modulo registers and the selected prescaler output determines the frequency of the PWM output The frequency of an 8-bit PWM signal is variable in 256 increments. Writing $00FF (255) to the TIM counter modulo registers produces a PWM period of 256 times the internal bus clock period if the prescaler select value is 000. See 14.9.1 TIM Status and Control Register. The value in the TIM channel registers determines the pulse width of the PWM output. The pulse width of an 8-bit PWM signal is variable in 256 increments. Writing $0080 (128) to the TIM channel registers produces a duty cycle of 128/256 or 50%.
OVERFLOW PERIOD POLARITY = 1 (ELSxA = 0) TCHx PULSE WIDTH POLARITY = 0 (ELSxA = 1) TCHx
OVERFLOW
OVERFLOW
OUTPUT COMPARE
OUTPUT COMPARE
OUTPUT COMPARE
Figure 14-3. PWM Period and Pulse Width
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 123
Timer Interface Module (TIM)
14.4.4.1 Unbuffered PWM Signal Generation Any output compare channel can generate unbuffered PWM pulses as described in 14.4.4 Pulse Width Modulation (PWM). The pulses are unbuffered because changing the pulse width requires writing the new pulse width value over the old value currently in the TIM channel registers. An unsynchronized write to the TIM channel registers to change a pulse width value could cause incorrect operation for up to two PWM periods. For example, writing a new value before the counter reaches the old value but after the counter reaches the new value prevents any compare during that PWM period. Also, using a TIM overflow interrupt routine to write a new, smaller pulse width value may cause the compare to be missed. The TIM may pass the new value before it is written. Use the following methods to synchronize unbuffered changes in the PWM pulse width on channel x: * When changing to a shorter pulse width, enable channel x output compare interrupts and write the new value in the output compare interrupt routine. The output compare interrupt occurs at the end of the current pulse. The interrupt routine has until the end of the PWM period to write the new value. * When changing to a longer pulse width, enable TIM overflow interrupts and write the new value in the TIM overflow interrupt routine. The TIM overflow interrupt occurs at the end of the current PWM period. Writing a larger value in an output compare interrupt routine (at the end of the current pulse) could cause two output compares to occur in the same PWM period. NOTE In PWM signal generation, do not program the PWM channel to toggle on output compare. Toggling on output compare prevents reliable 0% duty cycle generation and removes the ability of the channel to self-correct in the event of software error or noise. Toggling on output compare also can cause incorrect PWM signal generation when changing the PWM pulse width to a new, much larger value. 14.4.4.2 Buffered PWM Signal Generation Channels 0 and 1 can be linked to form a buffered PWM channel whose output appears on the TCH0 pin. The TIM channel registers of the linked pair alternately control the pulse width of the output. Setting the MS0B bit in TIM channel 0 status and control register (TSC0) links channel 0 and channel 1. The TIM channel 0 registers initially control the pulse width on the TCH0 pin. Writing to the TIM channel 1 registers enables the TIM channel 1 registers to synchronously control the pulse width at the beginning of the next PWM period. At each subsequent overflow, the TIM channel registers (0 or 1) that control the pulse width are the ones written to last. TSC0 controls and monitors the buffered PWM function, and TIM channel 1 status and control register (TSC1) is unused. While the MS0B bit is set, the channel 1 pin, TCH1, is available as a general-purpose I/O pin. NOTE In buffered PWM signal generation, do not write new pulse width values to the currently active channel registers. User software should track the currently active channel to prevent writing a new value to the active channel. Writing to the active channel registers is the same as generating unbuffered PWM signals.
MC68HC908QY/QT Family Data Sheet, Rev. 5 124 Freescale Semiconductor
Interrupts
14.4.4.3 PWM Initialization To ensure correct operation when generating unbuffered or buffered PWM signals, use the following initialization procedure: 1. In the TIM status and control register (TSC): a. Stop the TIM counter by setting the TIM stop bit, TSTOP. b. Reset the TIM counter and prescaler by setting the TIM reset bit, TRST. 2. In the TIM counter modulo registers (TMODH:TMODL), write the value for the required PWM period. 3. In the TIM channel x registers (TCHxH:TCHxL), write the value for the required pulse width. 4. In TIM channel x status and control register (TSCx): a. Write 0:1 (for unbuffered output compare or PWM signals) or 1:0 (for buffered output compare or PWM signals) to the mode select bits, MSxB:MSxA. See Table 14-3. b. Write 1 to the toggle-on-overflow bit, TOVx. c. Write 1:0 (polarity 1 -- to clear output on compare) or 1:1 (polarity 0 -- to set output on compare) to the edge/level select bits, ELSxB:ELSxA. The output action on compare must force the output to the complement of the pulse width level. See Table 14-3. NOTE In PWM signal generation, do not program the PWM channel to toggle on output compare. Toggling on output compare prevents reliable 0% duty cycle generation and removes the ability of the channel to self-correct in the event of software error or noise. Toggling on output compare can also cause incorrect PWM signal generation when changing the PWM pulse width to a new, much larger value. 5. In the TIM status control register (TSC), clear the TIM stop bit, TSTOP. Setting MS0B links channels 0 and 1 and configures them for buffered PWM operation. The TIM channel 0 registers (TCH0H:TCH0L) initially control the buffered PWM output. TIM status control register 0 (TSCR0) controls and monitors the PWM signal from the linked channels. MS0B takes priority over MS0A. Clearing the toggle-on-overflow bit, TOVx, inhibits output toggles on TIM overflows. Subsequent output compares try to force the output to a state it is already in and have no effect. The result is a 0% duty cycle output. Setting the channel x maximum duty cycle bit (CHxMAX) and setting the TOVx bit generates a 100% duty cycle output. See 14.9.4 TIM Channel Status and Control Registers.
14.5 Interrupts
The following TIM sources can generate interrupt requests: * TIM overflow flag (TOF) -- The TOF bit is set when the TIM counter reaches the modulo value programmed in the TIM counter modulo registers. The TIM overflow interrupt enable bit, TOIE, enables TIM overflow CPU interrupt requests. TOF and TOIE are in the TIM status and control register. * TIM channel flags (CH1F:CH0F) -- The CHxF bit is set when an input capture or output compare occurs on channel x. Channel x TIM CPU interrupt requests are controlled by the channel x interrupt enable bit, CHxIE. Channel x TIM CPU interrupt requests are enabled when CHxIE =1. CHxF and CHxIE are in the TIM channel x status and control register.
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 125
Timer Interface Module (TIM)
14.6 Wait Mode
The WAIT instruction puts the MCU in low power-consumption standby mode. The TIM remains active after the execution of a WAIT instruction. In wait mode the TIM registers are not accessible by the CPU. Any enabled CPU interrupt request from the TIM can bring the MCU out of wait mode. If TIM functions are not required during wait mode, reduce power consumption by stopping the TIM before executing the WAIT instruction.
14.7 TIM During Break Interrupts
A break interrupt stops the TIM counter. The system integration module (SIM) controls whether status bits in other modules can be cleared during the break state. The BCFE bit in the break flag control register (BFCR) enables software to clear status bits during the break state. See 13.8.2 Break Flag Control Register. To allow software to clear status bits during a break interrupt, write a 1 to the BCFE bit. If a status bit is cleared during the break state, it remains cleared when the MCU exits the break state. To protect status bits during the break state, write a 0 to the BCFE bit. With BCFE at 0 (its default state), software can read and write I/O registers during the break state without affecting status bits. Some status bits have a two-step read/write clearing procedure. If software does the first step on such a bit before the break, the bit cannot change during the break state as long as BCFE is at 0. After the break, doing the second step clears the status bit.
14.8 Input/Output Signals
Port A shares three of its pins with the TIM. Two TIM channel I/O pins are PTA0/TCH0 and PTA1/TCH1 and an alternate clock source is PTA2/TCLK.
14.8.1 TIM Clock Pin (PTA2/TCLK)
PTA2/TCLK is an external clock input that can be the clock source for the TIM counter instead of the
prescaled internal bus clock. Select the PTA2/TCLK input by writing 1s to the three prescaler select bits, PS[2-0]. (See 14.9.1 TIM Status and Control Register.) When the PTA2/TCLK pin is the TIM clock input, it is an input regardless of port pin initialization.
14.8.2 TIM Channel I/O Pins (PTA0/TCH0 and PTA1/TCH1)
Each channel I/O pin is programmable independently as an input capture pin or an output compare pin. PTA0/TCH0 can be configured as a buffered output compare or buffered PWM pin.
14.9 Input/Output Registers
The following I/O registers control and monitor operation of the TIM: * TIM status and control register (TSC) * TIM counter registers (TCNTH:TCNTL) * TIM counter modulo registers (TMODH:TMODL) * TIM channel status and control registers (TSC0 and TSC1) * TIM channel registers (TCH0H:TCH0L and TCH1H:TCH1L)
MC68HC908QY/QT Family Data Sheet, Rev. 5 126 Freescale Semiconductor
Input/Output Registers
14.9.1 TIM Status and Control Register
The TIM status and control register (TSC) does the following: * Enables TIM overflow interrupts * Flags TIM overflows * Stops the TIM counter * Resets the TIM counter * Prescales the TIM counter clock
Address: $0020 Bit 7 Read: Write: Reset: TOF 0 0 6 TOIE 0 = Unimplemented 5 TSTOP 1 4 0 TRST 0 0 3 0 2 PS2 0 1 PS1 0 Bit 0 PS0 0
Figure 14-4. TIM Status and Control Register (TSC) TOF -- TIM Overflow Flag Bit This read/write flag is set when the TIM counter reaches the modulo value programmed in the TIM counter modulo registers. Clear TOF by reading the TIM status and control register when TOF is set and then writing a 0 to TOF. If another TIM overflow occurs before the clearing sequence is complete, then writing 0 to TOF has no effect. Therefore, a TOF interrupt request cannot be lost due to inadvertent clearing of TOF. Reset clears the TOF bit. Writing a 1 to TOF has no effect. 1 = TIM counter has reached modulo value 0 = TIM counter has not reached modulo value TOIE -- TIM Overflow Interrupt Enable Bit This read/write bit enables TIM overflow interrupts when the TOF bit becomes set. Reset clears the TOIE bit. 1 = TIM overflow interrupts enabled 0 = TIM overflow interrupts disabled TSTOP -- TIM Stop Bit This read/write bit stops the TIM counter. Counting resumes when TSTOP is cleared. Reset sets the TSTOP bit, stopping the TIM counter until software clears the TSTOP bit. 1 = TIM counter stopped 0 = TIM counter active NOTE Do not set the TSTOP bit before entering wait mode if the TIM is required to exit wait mode. When the TSTOP bit is set and the timer is configured for input capture operation, input captures are inhibited until the TSTOP bit is cleared. When using TSTOP to stop the timer counter, see if any timer flags are set. If a timer flag is set, it must be cleared by clearing TSTOP, then clearing the flag, then setting TSTOP again.
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 127
Timer Interface Module (TIM)
TRST -- TIM Reset Bit Setting this write-only bit resets the TIM counter and the TIM prescaler. Setting TRST has no effect on any other registers. Counting resumes from $0000. TRST is cleared automatically after the TIM counter is reset and always reads as a 0. Reset clears the TRST bit. 1 = Prescaler and TIM counter cleared 0 = No effect NOTE Setting the TSTOP and TRST bits simultaneously stops the TIM counter at a value of $0000. PS[2:0] -- Prescaler Select Bits These read/write bits select either the PTA2/TCLK pin or one of the seven prescaler outputs as the input to the TIM counter as Table 14-2 shows. Reset clears the PS[2:0] bits. Table 14-2. Prescaler Selection
PS2 0 0 0 0 1 1 1 1 PS1 0 0 1 1 0 0 1 1 PS0 0 1 0 1 0 1 0 1 TIM Clock Source Internal bus clock / 1 Internal bus clock / 2 Internal bus clock / 4 Internal bus clock / 8 Internal bus clock / 16 Internal bus clock / 32 Internal bus clock / 64 PTA2/TCLK
14.9.2 TIM Counter Registers
The two read-only TIM counter registers contain the high and low bytes of the value in the TIM counter. Reading the high byte (TCNTH) latches the contents of the low byte (TCNTL) into a buffer. Subsequent reads of TCNTH do not affect the latched TCNTL value until TCNTL is read. Reset clears the TIM counter registers. Setting the TIM reset bit (TRST) also clears the TIM counter registers. NOTE If you read TCNTH during a break interrupt, be sure to unlatch TCNTL by reading TCNTL before exiting the break interrupt. Otherwise, TCNTL retains the value latched during the break.
Address: $0021 Bit 7 Read: Bit 15 Write: Reset: 0 Address: $0022 Bit 7 Read: Bit 7 Write: Reset: 0 TCNTH 6 Bit 14 0 TCNTL 6 Bit 6 5 Bit 5 4 Bit 4 0 3 Bit 3 0 2 Bit 2 0 1 Bit 1 0 Bit 0 Bit 0 0
5 Bit 13 0
4 Bit 12 0
3 Bit 11 0
2 Bit 10 0
1 Bit 9 0
Bit 0 Bit 8 0
0 0 = Unimplemented
Figure 14-5. TIM Counter Registers (TCNTH:TCNTL)
MC68HC908QY/QT Family Data Sheet, Rev. 5 128 Freescale Semiconductor
Input/Output Registers
14.9.3 TIM Counter Modulo Registers
The read/write TIM modulo registers contain the modulo value for the TIM counter. When the TIM counter reaches the modulo value, the overflow flag (TOF) becomes set, and the TIM counter resumes counting from $0000 at the next timer clock. Writing to the high byte (TMODH) inhibits the TOF bit and overflow interrupts until the low byte (TMODL) is written. Reset sets the TIM counter modulo registers.
Address: $0023 Bit 7 Read: Write: Reset: Bit 15 1 TMODH 6 Bit 14 1 TMODL 6 Bit 6 1 5 Bit 5 1 4 Bit 4 1 3 Bit 3 1 2 Bit 2 1 1 Bit 1 1 Bit 0 Bit 0 1 5 Bit 13 1 4 Bit 12 1 3 Bit 11 1 2 Bit 10 1 1 Bit 9 1 Bit 0 Bit 8 1
Address: $0024 Bit 7 Read: Write: Reset: Bit 7 1
Figure 14-6. TIM Counter Modulo Registers (TMODH:TMODL) NOTE Reset the TIM counter before writing to the TIM counter modulo registers.
14.9.4 TIM Channel Status and Control Registers
Each of the TIM channel status and control registers does the following: * Flags input captures and output compares * Enables input capture and output compare interrupts * Selects input capture, output compare, or PWM operation * Selects high, low, or toggling output on output compare * Selects rising edge, falling edge, or any edge as the active input capture trigger * Selects output toggling on TIM overflow * Selects 0% and 100% PWM duty cycle * Selects buffered or unbuffered output compare/PWM operation
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 129
Timer Interface Module (TIM) Address: $0025 Bit 7 Read: Write: Reset: CH0F 0 0 TSC0 6 CH0IE 0 TSC1 6 CH1IE 0 = Unimplemented 5 0 0 4 MS1A 0 3 ELS1B 0 2 ELS1A 0 1 TOV1 0 Bit 0 CH1MAX 0 5 MS0B 0 4 MS0A 0 3 ELS0B 0 2 ELS0A 0 1 TOV0 0 Bit 0 CH0MAX 0
Address: $0028 Bit 7 Read: Write: Reset: CH1F 0 0
Figure 14-7. TIM Channel Status and Control Registers (TSC0:TSC1) CHxF -- Channel x Flag Bit When channel x is an input capture channel, this read/write bit is set when an active edge occurs on the channel x pin. When channel x is an output compare channel, CHxF is set when the value in the TIM counter registers matches the value in the TIM channel x registers. Clear CHxF by reading the TIM channel x status and control register with CHxF set and then writing a 0 to CHxF. If another interrupt request occurs before the clearing sequence is complete, then writing a 0 to CHxF has no effect. Therefore, an interrupt request cannot be lost due to inadvertent clearing of CHxF. Reset clears the CHxF bit. Writing a 1 to CHxF has no effect. 1 = Input capture or output compare on channel x 0 = No input capture or output compare on channel x CHxIE -- Channel x Interrupt Enable Bit This read/write bit enables TIM CPU interrupt service requests on channel x. Reset clears the CHxIE bit. 1 = Channel x CPU interrupt requests enabled 0 = Channel x CPU interrupt requests disabled MSxB -- Mode Select Bit B This read/write bit selects buffered output compare/PWM operation. MSxB exists only in the TIM channel 0 status and control register. Setting MS0B disables the channel 1 status and control register and reverts TCH1 to general-purpose I/O. Reset clears the MSxB bit. 1 = Buffered output compare/PWM operation enabled 0 = Buffered output compare/PWM operation disabled MSxA -- Mode Select Bit A When ELSxB:A 00, this read/write bit selects either input capture operation or unbuffered output compare/PWM operation. See Table 14-3. 1 = Unbuffered output compare/PWM operation 0 = Input capture operation
MC68HC908QY/QT Family Data Sheet, Rev. 5 130 Freescale Semiconductor
Input/Output Registers
When ELSxB:A = 00, this read/write bit selects the initial output level of the TCHx pin (see Table 14-3). Reset clears the MSxA bit. 1 = Initial output level low 0 = Initial output level high NOTE Before changing a channel function by writing to the MSxB or MSxA bit, set the TSTOP and TRST bits in the TIM status and control register (TSC). Table 14-3. Mode, Edge, and Level Selection
MSxB X X 0 0 0 0 0 0 0 1 1 1 MSxA 0 1 0 0 0 1 1 1 1 X X X ELSxB 0 0 0 1 1 0 0 1 1 0 1 1 ELSxA 0 0 1 0 1 0 1 0 1 1 0 1 Buffered output compare or buffered PWM Output compare or PWM Input capture Mode Output preset Configuration Pin under port control; initial output level high Pin under port control; initial output level low Capture on rising edge only Capture on falling edge only Capture on rising or falling edge Software compare only Toggle output on compare Clear output on compare Set output on compare Toggle output on compare Clear output on compare Set output on compare
ELSxB and ELSxA -- Edge/Level Select Bits When channel x is an input capture channel, these read/write bits control the active edge-sensing logic on channel x. When channel x is an output compare channel, ELSxB and ELSxA control the channel x output behavior when an output compare occurs. When ELSxB and ELSxA are both clear, channel x is not connected to an I/O port, and pin TCHx is available as a general-purpose I/O pin. Table 14-3 shows how ELSxB and ELSxA work. Reset clears the ELSxB and ELSxA bits. NOTE After initially enabling a TIM channel register for input capture operation and selecting the edge sensitivity, clear CHxF to ignore any erroneous edge detection flags. TOVx -- Toggle-On-Overflow Bit When channel x is an output compare channel, this read/write bit controls the behavior of the channel x output when the TIM counter overflows. When channel x is an input capture channel, TOVx has no effect Reset clears the TOVx bit. 1 = Channel x pin toggles on TIM counter overflow. 0 = Channel x pin does not toggle on TIM counter overflow. NOTE When TOVx is set, a TIM counter overflow takes precedence over a channel x output compare if both occur at the same time.
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 131
Timer Interface Module (TIM)
CHxMAX -- Channel x Maximum Duty Cycle Bit When the TOVx bit is at a 1, setting the CHxMAX bit forces the duty cycle of buffered and unbuffered PWM signals to 100%. As Figure 14-8 shows, the CHxMAX bit takes effect in the cycle after it is set or cleared. The output stays at the 100% duty cycle level until the cycle after CHxMAX is cleared.
OVERFLOW PERIOD OVERFLOW OVERFLOW OVERFLOW OVERFLOW
TCHx
OUTPUT COMPARE CHxMAX
OUTPUT COMPARE
OUTPUT COMPARE
OUTPUT COMPARE
Figure 14-8. CHxMAX Latency
14.9.5 TIM Channel Registers
These read/write registers contain the captured TIM counter value of the input capture function or the output compare value of the output compare function. The state of the TIM channel registers after reset is unknown. In input capture mode (MSxB:MSxA = 0:0), reading the high byte of the TIM channel x registers (TCHxH) inhibits input captures until the low byte (TCHxL) is read. In output compare mode (MSxB:MSxA 0:0), writing to the high byte of the TIM channel x registers (TCHxH) inhibits output compares until the low byte (TCHxL) is written.
Address: $0026 Bit 7 Read: Bit 15 Write: Reset: Address: $0027 Bit 7 Read: Bit 7 Write: Reset: Address: $0029 Bit 7 Read: Bit 15 Write: Reset: Address: $02A Bit 7 Read: Bit 7 Write: Reset: TCH0H 6 Bit 14
5 Bit 13
4 Bit 12
3 Bit 11
2 Bit 10
1 Bit 9
Bit 0 Bit 8
Indeterminate after reset TCH0L 6 Bit 6
5 Bit 5
4 Bit 4
3 Bit 3
2 Bit 2
1 Bit 1
Bit 0 Bit 0
Indeterminate after reset TCH1H 6 Bit 14
5 Bit 13
4 Bit 12
3 Bit 11
2 Bit 10
1 Bit 9
Bit 0 Bit 8
Indeterminate after reset TCH1L 6 Bit 6
5 Bit 5
4 Bit 4
3 Bit 3
2 Bit 2
1 Bit 1
Bit 0 Bit 0
Indeterminate after reset
Figure 14-9. TIM Channel Registers (TCH0H/L:TCH1H/L)
MC68HC908QY/QT Family Data Sheet, Rev. 5 132 Freescale Semiconductor
Chapter 15 Development Support
15.1 Introduction
This section describes the break module, the monitor read-only memory (MON), and the monitor mode entry methods.
15.2 Break Module (BRK)
The break module can generate a break interrupt that stops normal program flow at a defined address to enter a background program. Features include: * Accessible input/output (I/O) registers during the break Interrupt * Central processor unit (CPU) generated break interrupts * Software-generated break interrupts * Computer operating properly (COP) disabling during break interrupts
15.2.1 Functional Description
When the internal address bus matches the value written in the break address registers, the break module issues a breakpoint signal (BKPT) to the system integration module (SIM). The SIM then causes the CPU to load the instruction register with a software interrupt instruction (SWI). The program counter vectors to $FFFC and $FFFD ($FEFC and $FEFD in monitor mode). The following events can cause a break interrupt to occur: * A CPU generated address (the address in the program counter) matches the contents of the break address registers. * Software writes a 1 to the BRKA bit in the break status and control register. When a CPU generated address matches the contents of the break address registers, the break interrupt is generated. A return-from-interrupt instruction (RTI) in the break routine ends the break interrupt and returns the microcontroller unit (MCU) to normal operation. Figure 15-2 shows the structure of the break module.
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 133
Development Support
PTA0/AD0/TCH0/KBI0 PTA1/AD1/TCH1/KBI1 DDRA PTA PTA2/IRQ/KBI2/TCLK PTA3/RST/KBI3 PTA4/OSC2/AD2/KBI4 PTA5/OSC1/AD3/KBI5 M68HC08 CPU PTB0 PTB1 PTB2 PTB3 PTB4 PTB5 PTB6 PTB7 CLOCK GENERATOR (OSCILLATOR)
SYSTEM INTEGRATION MODULE SINGLE INTERRUPT MODULE BREAK MODULE POWER-ON RESET MODULE MC68HC908QY4 AND MC68HC908QT4 4096 BYTES MC68HC908QY2, MC68HC908QY1, MC68HC908QT2, AND MC68HC908QT1: 1536 BYTES USER FLASH KEYBOARD INTERRUPT MODULE 16-BIT TIMER MODULE COP MODULE VDD
8-BIT ADC
128 BYTES RAM
POWER SUPPLY VSS
DDRB
PTB
MONITOR ROM
RST, IRQ: Pins have internal (about 30K Ohms) pull up PTA[0:5]: High current sink and source capability PTA[0:5]: Pins have programmable keyboard interrupt and pull up PTB[0:7]: Not available on 8-pin devices - MC68HC908QT1, MC68HC908QT2, and MC68HC908QT4 (see note in 12.1 Introduction) ADC: Not available on the MC68HC908QY1 and MC68HC908QT1
Figure 15-1. Block Diagram Highlighting BRK and MON Blocks
ADDRESS BUS[15:8]
BREAK ADDRESS REGISTER HIGH 8-BIT COMPARATOR ADDRESS BUS[15:0] 8-BIT COMPARATOR BREAK ADDRESS REGISTER LOW CONTROL BKPT (TO SIM)
ADDRESS BUS[7:0]
Figure 15-2. Break Module Block Diagram
MC68HC908QY/QT Family Data Sheet, Rev. 5 134 Freescale Semiconductor
Break Module (BRK)
When the internal address bus matches the value written in the break address registers or when software writes a 1 to the BRKA bit in the break status and control register, the CPU starts a break interrupt by: * Loading the instruction register with the SWI instruction * Loading the program counter with $FFFC and $FFFD ($FEFC and $FEFD in monitor mode) The break interrupt timing is: * When a break address is placed at the address of the instruction opcode, the instruction is not executed until after completion of the break interrupt routine. * When a break address is placed at an address of an instruction operand, the instruction is executed before the break interrupt. * When software writes a 1 to the BRKA bit, the break interrupt occurs just before the next instruction is executed. By updating a break address and clearing the BRKA bit in a break interrupt routine, a break interrupt can be generated continuously. CAUTION A break address should be placed at the address of the instruction opcode. When software does not change the break address and clears the BRKA bit in the first break interrupt routine, the next break interrupt will not be generated after exiting the interrupt routine even when the internal address bus matches the value written in the break address registers. 15.2.1.1 Flag Protection During Break Interrupts The system integration module (SIM) controls whether or not module status bits can be cleared during the break state. The BCFE bit in the break flag control register (BFCR) enables software to clear status bits during the break state. See 13.8.2 Break Flag Control Register and the Break Interrupts subsection for each module. 15.2.1.2 TIM During Break Interrupts A break interrupt stops the timer counter. 15.2.1.3 COP During Break Interrupts The COP is disabled during a break interrupt with monitor mode when BDCOP bit is set in break auxiliary register (BRKAR).
15.2.2 Break Module Registers
These registers control and monitor operation of the break module: * Break status and control register (BRKSCR) * Break address register high (BRKH) * Break address register low (BRKL) * Break status register (BSR) * Break flag control register (BFCR)
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 135
Development Support
15.2.2.1 Break Status and Control Register The break status and control register (BRKSCR) contains break module enable and status bits.
Address: $FE0B Bit 7 Read: Write: Reset: BRKE 0 6 BRKA 0 5 0 0 4 0 0 3 0 0 2 0 0 1 0 0 Bit 0 0 0
= Unimplemented
Figure 15-3. Break Status and Control Register (BRKSCR) BRKE -- Break Enable Bit This read/write bit enables breaks on break address register matches. Clear BRKE by writing a 0 to bit 7. Reset clears the BRKE bit. 1 = Breaks enabled on 16-bit address match 0 = Breaks disabled BRKA -- Break Active Bit This read/write status and control bit is set when a break address match occurs. Writing a 1 to BRKA generates a break interrupt. Clear BRKA by writing a 0 to it before exiting the break routine. Reset clears the BRKA bit. 1 = Break address match 0 = No break address match 15.2.2.2 Break Address Registers The break address registers (BRKH and BRKL) contain the high and low bytes of the desired breakpoint address. Reset clears the break address registers.
Address: $FE09 Bit 7 Read: Write: Reset: Bit 15 0 6 Bit 14 0 5 Bit 13 0 4 Bit 12 0 3 Bit 11 0 2 Bit 10 0 1 Bit 9 0 Bit 0 Bit 8 0
Figure 15-4. Break Address Register High (BRKH)
Address: $FE0A Bit 7 Read: Write: Reset: Bit 7 0 6 Bit 6 0 5 Bit 5 0 4 Bit 4 0 3 Bit 3 0 2 Bit 2 0 1 Bit 1 0 Bit 0 Bit 0 0
Figure 15-5. Break Address Register Low (BRKL)
MC68HC908QY/QT Family Data Sheet, Rev. 5 136 Freescale Semiconductor
Break Module (BRK)
15.2.2.3 Break Auxiliary Register The break auxiliary register (BRKAR) contains a bit that enables software to disable the COP while the MCU is in a state of break interrupt with monitor mode.
Address: $FE02 Bit 7 Read: Write: Reset: 0 0 = Unimplemented 0 0 0 0 0 0 6 0 5 0 4 0 3 0 2 0 1 0 Bit 0 BDCOP 0
Figure 15-6. Break Auxiliary Register (BRKAR) BDCOP -- Break Disable COP Bit This read/write bit disables the COP during a break interrupt. Reset clears the BDCOP bit. 1 = COP disabled during break interrupt 0 = COP enabled during break interrupt 15.2.2.4 Break Status Register The break status register (BSR) contains a flag to indicate that a break caused an exit from wait mode. This register is only used in emulation mode.
Address: $FE00 Bit 7 Read: Write: Reset: R = Reserved 1. Writing a 0 clears SBSW. R 6 R 5 R 4 R 3 R 2 R 1 SBSW Note(1) 0 Bit 0 R
Figure 15-7. Break Status Register (BSR) SBSW -- SIM Break Stop/Wait SBSW can be read within the break state SWI routine. The user can modify the return address on the stack by subtracting one from it. 1 = Wait mode was exited by break interrupt 0 = Wait mode was not exited by break interrupt
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 137
Development Support
15.2.2.5 Break Flag Control Register The break control register (BFCR) contains a bit that enables software to clear status bits while the MCU is in a break state.
Address: $FE03 Bit 7 Read: Write: Reset: BCFE 0 R = Reserved 6 R 5 R 4 R 3 R 2 R 1 R Bit 0 R
Figure 15-8. Break Flag Control Register (BFCR) BCFE -- Break Clear Flag Enable Bit This read/write bit enables software to clear status bits by accessing status registers while the MCU is in a break state. To clear status bits during the break state, the BCFE bit must be set. 1 = Status bits clearable during break 0 = Status bits not clearable during break
15.2.3 Low-Power Modes
The WAIT and STOP instructions put the MCU in low power- consumption standby modes. If enabled, the break module will remain enabled in wait and stop modes. However, since the internal address bus does not increment in these modes, a break interrupt will never be triggered.
15.3 Monitor Module (MON)
This subsection describes the monitor module (MON) and the monitor mode entry methods. The monitor allows debugging and programming of the microcontroller unit (MCU) through a single-wire interface with a host computer. Monitor mode entry can be achieved without use of the higher test voltage, VTST, as long as vector addresses $FFFE and $FFFF are blank, thus reducing the hardware requirements for in-circuit programming. Features include: * Normal user-mode pin functionality on most pins * One pin dedicated to serial communication between MCU and host computer * Standard non-return-to-zero (NRZ) communication with host computer * Execution of code in random-access memory (RAM) or FLASH * FLASH memory security feature(1) * FLASH memory programming interface * Use of external 9.8304 MHz oscillator to generate internal frequency of 2.4576 MHz * Simple internal oscillator mode of operation (no external clock or high voltage) * Monitor mode entry without high voltage, VTST, if reset vector is blank ($FFFE and $FFFF contain $FF) * Standard monitor mode entry if high voltage is applied to IRQ
1. No security feature is absolutely secure. However, Freescale's strategy is to make reading or copying the FLASH difficult for unauthorized users. MC68HC908QY/QT Family Data Sheet, Rev. 5 138 Freescale Semiconductor
Monitor Module (MON)
15.3.1 Functional Description
Figure 15-9 shows a simplified diagram of monitor mode entry. The monitor module receives and executes commands from a host computer. Figure 15-10, Figure 15-11, and Figure 15-12 show example circuits used to enter monitor mode and communicate with a host computer via a standard RS-232 interface.
POR RESET
NO
IRQ = VTST?
YES
CONDITIONS FROM Table 15-1
PTA0 = 1, RESET VECTOR BLANK? YES FORCED MONITOR MODE
NO
PTA0 = 1, PTA1 = 1, AND PTA4 = 0? YES NORMAL USER MODE NORMAL MONITOR MODE
NO
INVALID USER MODE
HOST SENDS 8 SECURITY BYTES
IS RESET POR? NO
YES
YES
ARE ALL SECURITY BYTES CORRECT?
NO
ENABLE FLASH
DISABLE FLASH
MONITOR MODE ENTRY
DEBUGGING AND FLASH PROGRAMMING (IF FLASH IS ENABLED)
EXECUTE MONITOR CODE
YES
DOES RESET OCCUR?
NO
Figure 15-9. Simplified Monitor Mode Entry Flowchart
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 139
Development Support
VDD VDD
10 k* RST (PTA3) MAX232 1 1 F + 3 4 1 F + 5 C2- DB9 2 3 5 7 8 10 9 74HC125 3 2 1 C1+ 16 + C1- C2+ 15 + V+ 2 V- 6 1 F + 10 k 74HC125 5 6 4 VTST 1 F 1 F 1 k VDD 9.8304 MHz CLOCK OSC1 (PTA5)
VDD 0.1 F
VDD
10 k* PTA1 IRQ (PTA2)
VDD 9.1 V
10 k* PTA4 PTA0 VSS
* Value not critical
Figure 15-10. Monitor Mode Circuit (External Clock, with High Voltage)
VDD N.C. RST (PTA3) VDD 0.1 F MAX232 1 1 F + 3 4 1 F + 5 C2- DB9 2 3 5 7 8 10 9 74HC125 3 2 1 C1+ 16 + C1- C2+ 15 + V+ 2 V- 6 1 F + 10 k 74HC125 5 6 4 1 F 1 F 10 k* VDD IRQ (PTA2) PTA4 N.C. PTA1 N.C. VDD 9.8304 MHz CLOCK OSC1 (PTA5)
PTA0 VSS
* Value not critical
Figure 15-11. Monitor Mode Circuit (External Clock, No High Voltage)
MC68HC908QY/QT Family Data Sheet, Rev. 5 140 Freescale Semiconductor
Monitor Module (MON)
VDD N.C. RST (PTA3)
VDD 0.1 F
MAX232 1 1 F + 3 4 1 F + 5 C2- DB9 2 3 5 7 8 10 9 C1+ 16
VDD +
N.C.
OSC1 (PTA5)
1 F + 1 F 10 k* IRQ (PTA2)
C1- C2+
15
PTA1
N.C.
V+ 2 V- 6 1 F + 10 k 74HC125 5 6 74HC125 3 2 1 4
PTA4 VDD
N.C.
PTA0
VSS
* Value not critical
Figure 15-12. Monitor Mode Circuit (Internal Clock, No High Voltage) Simple monitor commands can access any memory address. In monitor mode, the MCU can execute code downloaded into RAM by a host computer while most MCU pins retain normal operating mode functions. All communication between the host computer and the MCU is through the PTA0 pin. A level-shifting and multiplexing interface is required between PTA0 and the host computer. PTA0 is used in a wired-OR configuration and requires a pullup resistor. The monitor code has been updated from previous versions of the monitor code to allow enabling the internal oscillator to generate the internal clock. This addition, which is enabled when IRQ is held low out of reset, is intended to support serial communication/programming at 9600 baud in monitor mode by using the internal oscillator, and the internal oscillator user trim value OSCTRIM (FLASH location $FFC0, if programmed) to generate the desired internal frequency (3.2 MHz). Since this feature is enabled only when IRQ is held low out of reset, it cannot be used when the reset vector is programmed (i.e., the value is not $FFFF) because entry into monitor mode in this case requires VTST on IRQ. The IRQ pin must remain low during this monitor session in order to maintain communication. Table 15-1 shows the pin conditions for entering monitor mode. As specified in the table, monitor mode may be entered after a power-on reset (POR) and will allow communication at 9600 baud provided one of the following sets of conditions is met: * If $FFFE and $FFFF do not contain $FF (programmed state): - The external clock is 9.8304 MHz - IRQ = VTST * If $FFFE and $FFFF contain $FF (erased state): - The external clock is 9.8304 MHz - IRQ = VDD (this can be implemented through the internal IRQ pullup) * If $FFFE and $FFFF contain $FF (erased state): - IRQ = VSS (internal oscillator is selected, no external clock required)
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 141
Development Support
Table 15-1. Monitor Mode Signal Requirements and Options
Serial Mode CommuniSelection RST Reset IRQ cation (PTA2) (PTA3) Vector PTA0 PTA1 PTA4 VTST VDD VSS X VTST [6] VDD X X X RST [4] X $FFFF (blank) $FFFF (blank) Not $FFFF -- 1 1 1 X COM [8] 1 X X X 0 X X X Communication Speed External Bus Clock Frequency Disabled Disabled Disabled Enabled 9.8304 MHz 9.8304 MHz X X OSC1 [13] 2.4576 MHz 2.4576 MHz 3.2 MHz (Trimmed) X Baud Rate 9600 9600 9600 X Provide external clock at OSC1. Provide external clock at OSC1. Internal clock is active.
Mode
COP
Comments
Normal Monitor Forced Monitor
User MON08 Function [Pin No.]
MOD0 MOD1 [12] [10]
--
--
--
1. PTA0 must have a pullup resistor to VDD in monitor mode. 2. Communication speed in the table is an example to obtain a baud rate of 9600. Baud rate using external oscillator is bus frequency / 256 and baud rate using internal oscillator is bus frequency / 335. 3. External clock is a 9.8304 MHz oscillator on OSC1. 4. X = don't care 5. MON08 pin refers to P&E Microcomputer Systems' MON08-Cyclone 2 by 8-pin connector. NC NC NC NC NC NC OSC1 VDD 1 3 5 7 9 11 13 15 2 4 6 8 10 12 14 16 GND RST IRQ PTA0 PTA4 PTA1 NC NC
The rising edge of the internal RST signal latches the monitor mode. Once monitor mode is latched, the values on PTA1 and PTA4 pins can be changed. Once out of reset, the MCU waits for the host to send eight security bytes (see 15.3.2 Security). After the security bytes, the MCU sends a break signal (10 consecutive logic 0s) to the host, indicating that it is ready to receive a command. 15.3.1.1 Normal Monitor Mode RST and OSC1 functions will be active on the PTA3 and PTA5 pins respectively as long as VTST is applied to the IRQ pin. If the IRQ pin is lowered (no longer VTST) then the chip will still be operating in monitor mode, but the pin functions will be determined by the settings in the configuration registers (see Chapter 5 Configuration Register (CONFIG)) when VTST was lowered. With VTST lowered, the BIH and BIL instructions will read the IRQ pin state only if IRQEN is set in the CONFIG2 register.
MC68HC908QY/QT Family Data Sheet, Rev. 5 142 Freescale Semiconductor
Monitor Module (MON)
If monitor mode was entered with VTST on IRQ, then the COP is disabled as long as VTST is applied to IRQ. 15.3.1.2 Forced Monitor Mode If entering monitor mode without high voltage on IRQ, then startup port pin requirements and conditions, (PTA1/PTA4) are not in effect. This is to reduce circuit requirements when performing in-circuit programming. NOTE If the reset vector is blank and monitor mode is entered, the chip will see an additional reset cycle after the initial power-on reset (POR). Once the reset vector has been programmed, the traditional method of applying a voltage, VTST, to IRQ must be used to enter monitor mode. If monitor mode was entered as a result of the reset vector being blank, the COP is always disabled regardless of the state of IRQ. If the voltage applied to the IRQ is less than VTST, the MCU will come out of reset in user mode. Internal circuitry monitors the reset vector fetches and will assert an internal reset if it detects that the reset vectors are erased ($FF). When the MCU comes out of reset, it is forced into monitor mode without requiring high voltage on the IRQ pin. Once out of reset, the monitor code is initially executing with the internal clock at its default frequency. If IRQ is held high, all pins will default to regular input port functions except for PTA0 and PTA5 which will operate as a serial communication port and OSC1 input respectively (refer to Figure 15-10). That will allow the clock to be driven from an external source through OSC1 pin. If IRQ is held low, all pins will default to regular input port function except for PTA0 which will operate as serial communication port. Refer to Figure 15-11. Regardless of the state of the IRQ pin, it will not function as a port input pin in monitor mode. Bit 2 of the Port A data register will always read 0. The BIH and BIL instructions will behave as if the IRQ pin is enabled, regardless of the settings in the configuration register. See Chapter 5 Configuration Register (CONFIG). The COP module is disabled in forced monitor mode. Any reset other than a power-on reset (POR) will automatically force the MCU to come back to the forced monitor mode. 15.3.1.3 Monitor Vectors In monitor mode, the MCU uses different vectors for reset, SWI (software interrupt), and break interrupt than those for user mode. The alternate vectors are in the $FE page instead of the $FF page and allow code execution from the internal monitor firmware instead of user code. NOTE Exiting monitor mode after it has been initiated by having a blank reset vector requires a power-on reset (POR). Pulling RST (when RST pin available) low will not exit monitor mode in this situation. Table 15-2 summarizes the differences between user mode and monitor mode regarding vectors.
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 143
Development Support
Table 15-2. Mode Difference
Functions Modes User Monitor Reset Vector High $FFFE $FEFE Reset Vector Low $FFFF $FEFF Break Vector High $FFFC $FEFC Break Vector Low $FFFD $FEFD SWI Vector High $FFFC $FEFC SWI Vector Low $FFFD $FEFD
15.3.1.4 Data Format Communication with the monitor ROM is in standard non-return-to-zero (NRZ) mark/space data format. Transmit and receive baud rates must be identical.
START BIT NEXT START BIT
BIT 0
BIT 1
BIT 2
BIT 3
BIT 4
BIT 5
BIT 6
BIT 7
STOP BIT
Figure 15-13. Monitor Data Format 15.3.1.5 Break Signal A start bit (logic 0) followed by nine logic 0 bits is a break signal. When the monitor receives a break signal, it drives the PTA0 pin high for the duration of two bits and then echoes back the break signal.
MISSING STOP BIT 2-STOP BIT DELAY BEFORE ZERO ECHO
0
1
2
3
4
5
6
7
0
1
2
3
4
5
6
7
Figure 15-14. Break Transaction 15.3.1.6 Baud Rate The monitor communication baud rate is controlled by the frequency of the external or internal oscillator and the state of the appropriate pins as shown in Table 15-1. Table 15-1 also lists the bus frequencies to achieve standard baud rates. The effective baud rate is the bus frequency divided by 256 when using an external oscillator. When using the internal oscillator in forced monitor mode, the effective baud rate is the bus frequency divided by 335. 15.3.1.7 Commands The monitor ROM firmware uses these commands: * READ (read memory) * WRITE (write memory) * IREAD (indexed read) * IWRITE (indexed write) * READSP (read stack pointer) * RUN (run user program)
MC68HC908QY/QT Family Data Sheet, Rev. 5 144 Freescale Semiconductor
Monitor Module (MON)
The monitor ROM firmware echoes each received byte back to the PTA0 pin for error checking. An 11-bit delay at the end of each command allows the host to send a break character to cancel the command. A delay of two bit times occurs before each echo and before READ, IREAD, or READSP data is returned. The data returned by a read command appears after the echo of the last byte of the command. NOTE Wait one bit time after each echo before sending the next byte.
FROM HOST
READ
READ
ADDRESS HIGH
ADDRESS HIGH
ADDRESS LOW
ADDRESS LOW
DATA
4
1
4
1
4
1
3, 2
4 RETURN
ECHO Notes: 1 = Echo delay, 2 bit times 2 = Data return delay, 2 bit times
3 = Cancel command delay, 11 bit times 4 = Wait 1 bit time before sending next byte.
Figure 15-15. Read Transaction
FROM HOST
WRITE 3 ECHO 1
WRITE 3
ADDRESS HIGH
ADDRESS HIGH
ADDRESS LOW
ADDRESS LOW
DATA
DATA
1
3
1
3
1
2, 3
Notes: 1 = Echo delay, 2 bit times 2 = Cancel command delay, 11 bit times 3 = Wait 1 bit time before sending next byte.
Figure 15-16. Write Transaction A brief description of each monitor mode command is given in Table 15-3 through Table 15-8. Table 15-3. READ (Read Memory) Command
Description Operand Data Returned Opcode Read byte from memory 2-byte address in high-byte:low-byte order Returns contents of specified address $4A Command Sequence
SENT TO MONITOR
READ
READ
ADDRESS ADDRESS ADDRESS HIGH HIGH LOW
ADDRESS LOW
DATA
ECHO
RETURN
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 145
Development Support
Table 15-4. WRITE (Write Memory) Command
Description Operand Data Returned Opcode
FROM HOST
Write byte to memory 2-byte address in high-byte:low-byte order; low byte followed by data byte None $49 Command Sequence
WRITE
WRITE
ADDRESS HIGH
ADDRESS
HIGH
ADDRESS LOW
ADDRESS LOW
DATA
DATA
ECHO
Table 15-5. IREAD (Indexed Read) Command
Description Operand Data Returned Opcode Read next 2 bytes in memory from last address accessed None Returns contents of next two addresses $1A Command Sequence
FROM HOST
IREAD
IREAD
DATA
DATA
ECHO
RETURN
Table 15-6. IWRITE (Indexed Write) Command
Description Operand Data Returned Opcode Write to last address accessed + 1 Single data byte None $19 Command Sequence
FROM HOST
IWRITE ECHO
IWRITE
DATA
DATA
A sequence of IREAD or IWRITE commands can access a block of memory sequentially over the full 64-Kbyte memory map.
MC68HC908QY/QT Family Data Sheet, Rev. 5 146 Freescale Semiconductor
Monitor Module (MON)
Table 15-7. READSP (Read Stack Pointer) Command
Description Operand Data Returned Opcode Reads stack pointer None Returns incremented stack pointer value (SP + 1) in high-byte:low-byte order $0C Command Sequence
FROM HOST
READSP
READSP
SP HIGH
SP LOW
ECHO
RETURN
Table 15-8. RUN (Run User Program) Command
Description Operand Data Returned Opcode Executes PULH and RTI instructions None None $28 Command Sequence
FROM HOST
RUN ECHO
RUN
The MCU executes the SWI and PSHH instructions when it enters monitor mode. The RUN command tells the MCU to execute the PULH and RTI instructions. Before sending the RUN command, the host can modify the stacked CPU registers to prepare to run the host program. The READSP command returns the incremented stack pointer value, SP + 1. The high and low bytes of the program counter are at addresses SP + 5 and SP + 6.
SP HIGH BYTE OF INDEX REGISTER CONDITION CODE REGISTER ACCUMULATOR LOW BYTE OF INDEX REGISTER HIGH BYTE OF PROGRAM COUNTER LOW BYTE OF PROGRAM COUNTER SP + 1 SP + 2 SP + 3 SP + 4 SP + 5 SP + 6 SP + 7
Figure 15-17. Stack Pointer at Monitor Mode Entry
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 147
Development Support
15.3.2 Security
A security feature discourages unauthorized reading of FLASH locations while in monitor mode. The host can bypass the security feature at monitor mode entry by sending eight security bytes that match the bytes at locations $FFF6-$FFFD. Locations $FFF6-$FFFD contain user-defined data. NOTE Do not leave locations $FFF6-$FFFD blank. For security reasons, program locations $FFF6-$FFFD even if they are not used for vectors. During monitor mode entry, the MCU waits after the power-on reset for the host to send the eight security bytes on pin PTA0. If the received bytes match those at locations $FFF6-$FFFD, the host bypasses the security feature and can read all FLASH locations and execute code from FLASH. Security remains bypassed until a power-on reset occurs. If the reset was not a power-on reset, security remains bypassed and security code entry is not required. See Figure 15-18. Upon power-on reset, if the received bytes of the security code do not match the data at locations $FFF6-$FFFD, the host fails to bypass the security feature. The MCU remains in monitor mode, but reading a FLASH location returns an invalid value and trying to execute code from FLASH causes an illegal address reset. After receiving the eight security bytes from the host, the MCU transmits a break character, signifying that it is ready to receive a command. NOTE The MCU does not transmit a break character until after the host sends the eight security bytes. To determine whether the security code entered is correct, check to see if bit 6 of RAM address $80 is set. If it is, then the correct security code has been entered and FLASH can be accessed. If the security sequence fails, the device should be reset by a power-on reset and brought up in monitor mode to attempt another entry. After failing the security sequence, the FLASH module can also be mass erased by executing an erase routine that was downloaded into internal RAM. The mass erase operation clears the security code locations so that all eight security bytes become $FF (blank).
VDD 4096 + 32 CGMXCLK CYCLES COMMAND 1 BYTE 2 ECHO BYTE 8 ECHO 2 BREAK 4 1 COMMAND ECHO RST BYTE 1 BYTE 2 BYTE 8 1
FROM HOST PA0 256 BUS CYCLES (MINIMUM) FROM MCU 1 BYTE 1 ECHO 4
Notes: 1 = Echo delay, 2 bit times 2 = Data return delay, 2 bit times 4 = Wait 1 bit time before sending next byte.
Figure 15-18. Monitor Mode Entry Timing
MC68HC908QY/QT Family Data Sheet, Rev. 5 148 Freescale Semiconductor
Chapter 16 Electrical Specifications
16.1 Introduction
This section contains electrical and timing specifications.
16.2 Absolute Maximum Ratings
Maximum ratings are the extreme limits to which the microcontroller unit (MCU) can be exposed without permanently damaging it. NOTE This device is not guaranteed to operate properly at the maximum ratings. Refer to 16.5 5-V DC Electrical Characteristics and 16.9 3-V DC Electrical Characteristics for guaranteed operating conditions.
Characteristic(1) Supply voltage Input voltage Mode entry voltage, IRQ pin Maximum current per pin excluding PTA0-PTA5, VDD, and VSS Maximum current for pins PTA0-PTA5 Storage temperature Maximum current out of VSS Maximum current into VDD 1. Voltages references to VSS. Symbol VDD VIN VTST I IPTA0--IPTA5 TSTG IMVSS IMVDD Value -0.3 to +6.0 VSS -0.3 to VDD +0.3 VSS -0.3 to +9.1 15 25 -55 to +150 100 100 Unit V V V mA mA C mA mA
NOTE This device contains circuitry to protect the inputs against damage due to high static voltages or electric fields; however, it is advised that normal precautions be taken to avoid application of any voltage higher than maximum-rated voltages to this high-impedance circuit. For proper operation, it is recommended that VIN and VOUT be constrained to the range VSS (VIN or VOUT) VDD. Reliability of operation is enhanced if unused inputs are connected to an appropriate logic voltage level (for example, either VSS or VDD.)
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 149
Electrical Specifications
16.3 Functional Operating Range
Characteristic Symbol Value - 40 to +125 - 40 to +105 - 40 to +85 2.7 to 5.5 Unit Temp. Code M V C --
Operating temperature range Operating voltage range
TA VDD
C V
16.4 Thermal Characteristics
Characteristic Thermal resistance 8-pin PDIP 8-pin SOIC 8-pin DFN 16-pin PDIP 16-pin SOIC 16-pin TSSOP I/O pin power dissipation Power dissipation(1) Constant(2) Average junction temperature Maximum junction temperature Symbol Value 105 142 173 76 90 133 User determined PD = (IDD x VDD) + PI/O = K/(TJ + 273C) PD x (TA + 273C) + PD2 x JA TA + (PD x JA) 150 Unit
JA
C/W
PI/O PD K TJ TJM
W W W/C C C
1. Power dissipation is a function of temperature. 2. K constant unique to the device. K can be determined for a known TA and measured PD. With this value of K, PD and TJ can be determined for any value of TA.
MC68HC908QY/QT Family Data Sheet, Rev. 5 150 Freescale Semiconductor
5-V DC Electrical Characteristics
16.5 5-V DC Electrical Characteristics
Characteristic(1) Output high voltage ILoad = -2.0 mA, all I/O pins ILoad = -10.0 mA, all I/O pins ILoad = -15.0 mA, PTA0, PTA1, PTA3-PTA5 only Maximum combined IOH (all I/O pins) Output low voltage ILoad = 1.6 mA, all I/O pins ILoad = 10.0 mA, all I/O pins ILoad = 15.0 mA, PTA0, PTA1, PTA3-PTA5 only Maximum combined IOL (all I/O pins) Input high voltage PTA0-PTA5, PTB0-PTB7 Input low voltage PTA0-PTA5, PTB0-PTB7 Input hysteresis DC injection current, all ports Total dc current injection (sum of all I/O) Ports Hi-Z leakage current Capacitance Ports (as input) Ports (as input) POR rearm voltage(3) POR rise time ramp rate(4) Monitor mode entry voltage Pullup resistors PTA0-PTA5, PTB0-PTB7 Low-voltage inhibit reset, trip falling voltage Low-voltage inhibit reset, trip rising voltage Low-voltage inhibit reset/recover hysteresis
(5)
Symbol
Min VDD -0.4 VDD -1.5 VDD -0.8 -- -- -- -- -- 0.7 x VDD VSS 0.06 x VDD -2 -25 -1 -- -- 0 0.035 VDD + 2.5 16 3.90 4.00 --
Typ(2) -- -- -- -- -- -- -- -- -- -- -- -- -- 0.1 -- -- -- -- -- 26 4.20 4.30 100
Max -- -- -- 50 0.4 1.5 0.8 50 VDD 0.3 x VDD -- +2 +25 +1 12 8 100 -- 9.1 36 4.50 4.60 --
Unit
VOH
V
IOHT
mA
VOL
V
IOLT VIH VIL VHYS IINJ IINJTOT IIL CIN COUT VPOR RPOR VTST RPU VTRIPF VTRIPR VHYS
mA V V V mA mA A
pF mV V/ms V k V V mV
1. VDD = 4.5 to 5.5 Vdc, VSS = 0 Vdc, TA = TL to TH, unless otherwise noted. 2. Typical values reflect average measurements at midpoint of voltage range, 25C only. 3. Maximum is highest voltage that POR is guaranteed. 4. If minimum VDD is not reached before the internal POR reset is released, the LVI will hold the part in reset until minimum VDD is reached. 5. RPU is measured at VDD = 5.0 V.
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 151
Electrical Specifications
16.6 Typical 5-V Output Drive Characteristics
2.0
1.5 VDD-VOH (V) 5V PTA 5V PTB 0.5
1.0
0.0 0 -5 -10 -15 -20 -25 -30 -35 IOH (mA)
Figure 16-1. Typical 5-Volt Output High Voltage versus Output High Current (25C)
2.0
1.5 VOL (V)
1.0
5V PTA 5V PTB
0.5
0.0 0 5 10 15 20 25 30 35 IOL (mA)
Figure 16-2. Typical 5-Volt Output Low Voltage versus Output Low Current (25C)
MC68HC908QY/QT Family Data Sheet, Rev. 5 152 Freescale Semiconductor
5-V Control Timing
16.7 5-V Control Timing
Characteristic(1) Internal operating frequency Internal clock period (1/fOP) RST input pulse width low IRQ interrupt pulse width low (edge-triggered) IRQ interrupt pulse period Symbol fOP (fBus) tcyc tRL tILIH tILIL Min -- 125 100 100 Note(2) Max 8 -- -- -- -- Unit MHz ns ns ns tcyc
1. VDD = 4.5 to 5.5 Vdc, VSS = 0 Vdc, TA = TL to TH; timing shown with respect to 20% VDD and 70% VSS, unless otherwise noted. 2. The minimum period is the number of cycles it takes to execute the interrupt service routine plus 1 tcyc.
tRL RST tILIL tILIH IRQ
Figure 16-3. RST and IRQ Timing
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 153
Electrical Specifications
16.8 5-V Oscillator Characteristics
Characteristic Internal oscillator frequency(1)
(2)(3)
Symbol fINTCLK
Min -- -- -- -- 1 2 dc -- -- -- 0.5
Typ 12.8 0.4 2 -- -- -- -- 20 2 x CL 2 x CL 1 See Figure 16-4
Max -- -- -- 5 24 12 32 -- -- -- 10
Unit MHz
Deviation from trimmed Internal oscillator 12.8 MHz, fixed voltage, fixed temp 12.8 MHz, VDD 10%, 0 to 70C 12.8 MHz, VDD 10%, -40 to 125C Crystal frequency, XTALCLK(1)
ACCINT fOSCXCLK fRCCLK fOSCXCLK CL C1 C2 RB REXT
%
MHz MHz MHz pF -- -- M --
External RC oscillator frequency, RCCLK(1) External clock reference frequency(1) (4) Crystal load capacitance(5) Crystal fixed capacitance(3) Crystal tuning capacitance(3) Feedback bias resistor RC oscillator external resistor Crystal series damping resistor fOSCXCLK = 1 MHz fOSCXCLK = 4 MHz fOSCXCLK = > 8 MHz
RS
-- -- --
20 10 0
-- -- --
k
1. Bus frequency, fOP, is oscillator frequency divided by 4. 2. Deviation values assumes trimming @25C and midpoint of voltage range. 3. Values are based on characterization results, not tested in production. 4. No more than 10% duty cycle deviation from 50%. 5. Consult crystal vendor data sheet.
14 5 V 25C 12
RC FREQUENCY, f RCCLK (MHz)
10
8
6
4
2
0 0 10 20 30 R EXT (k ) 40 50 60
Figure 16-4. RC versus Frequency (5 Volts @ 25C)
MC68HC908QY/QT Family Data Sheet, Rev. 5 154 Freescale Semiconductor
3-V DC Electrical Characteristics
16.9 3-V DC Electrical Characteristics
Characteristic(1) Output high voltage ILoad = -0.6 mA, all I/O pins ILoad = -4.0 mA, all I/O pins ILoad = -10.0 mA, PTA0, PTA1, PTA3-PTA5 only Maximum combined IOH (all I/O pins) Output low voltage ILoad = 0.5 mA, all I/O pins ILoad = 6.0 mA, all I/O pins ILoad = 10.0 mA, PTA0, PTA1, PTA3-PTA5 only Maximum combined IOL (all I/O pins) Input high voltage PTA0-PTA5, PTB0-PTB7 Input low voltage PTA0-PTA5, PTB0-PTB7 Input hysteresis DC injection current, all ports Total dc current injection (sum of all I/O) Ports Hi-Z leakage current Capacitance Ports (as input) Ports (as input) POR rearm voltage(3) POR rise time ramp rate(4) Monitor mode entry voltage Pullup resistors PTA0-PTA5, PTB0-PTB7 Low-voltage inhibit reset, trip falling voltage Low-voltage inhibit reset, trip rising voltage Low-voltage inhibit reset/recover hysteresis
(5)
Symbol
Min VDD -0.3 VDD -1.0 VDD -0.8 -- -- -- -- -- 0.7 x VDD VSS 0.06 x VDD -2 -25 -1 -- -- 0 0.035 VDD + 2.5 16 2.40 2.50 --
Typ(2) -- -- -- -- -- -- -- -- -- -- -- -- -- 0.1 -- -- -- -- -- 26 2.55 2.65 60
Max -- -- -- 50 0.3 1.0 0.8 50 VDD 0.3 x VDD -- +2 +25 +1 12 8 100 -- VDD + 4.0 36 2.70 2.80 --
Unit
VOH
V
IOHT
mA
VOL
V
IOLT VIH VIL VHYS IINJ IINJTOT IIL CIN COUT VPOR RPOR VTST RPU VTRIPF VTRIPR VHYS
mA V V V mA mA A
pF mV V/ms V k V V mV
1. VDD = 2.7 to 3.3 Vdc, VSS = 0 Vdc, TA = TL to TH, unless otherwise noted. 2. Typical values reflect average measurements at midpoint of voltage range, 25C only. 3. Maximum is highest voltage that POR is guaranteed. 4. If minimum VDD is not reached before the internal POR reset is released, the LVI will hold the part in reset until minimum VDD is reached. 5. RPU are measured at VDD = 3.0 V
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 155
Electrical Specifications
16.10 Typical 3.0-V Output Drive Characteristics
1.5
1.0 VDD-VOH (V) 3V PTA 3V PTB 0.5
0.0 0 -5 -10 IOH (mA) -15 -20
Figure 16-5. Typical 3-Volt Output High Voltage versus Output High Current (25C)
1.5
1.0 VOL (V) 3V PTA 3V PTB 0.5
0.0 0 5 10 IOL (mA) 15 20
Figure 16-6. Typical 3-Volt Output Low Voltage versus Output Low Current (25C)
MC68HC908QY/QT Family Data Sheet, Rev. 5 156 Freescale Semiconductor
3-V Control Timing
16.11 3-V Control Timing
Characteristic(1) Internal operating frequency Internal clock period (1/fOP) RST input pulse width low IRQ interrupt pulse width low (edge-triggered) IRQ interrupt pulse period Symbol fOP (fBus) tcyc tRL tILIH tILIL Min -- 250 200 200 Note
(2)
Max 4 -- -- -- --
Unit MHz ns ns ns tcyc
1. VDD = 2.7 to 3.3 Vdc, VSS = 0 Vdc, TA = TL to TH; timing shown with respect to 20% VDD and 70% VDD, unless otherwise noted. 2. The minimum period is the number of cycles it takes to execute the interrupt service routine plus 1 tcyc.
tRL RST tILIL tILIH IRQ
Figure 16-7. RST and IRQ Timing
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 157
Electrical Specifications
16.12 3-V Oscillator Characteristics
Characteristic Internal oscillator frequency(1)
(2)(3)
Symbol fINTCLK
Min -- -- -- -- 1 2 dc -- -- -- 0.5
Typ 12.8 0.4 2 -- -- -- -- 20 2 x CL 2 x CL 1 See Figure 16-8
Max -- -- -- 5 16 10 16 -- -- -- 10
Unit MHz
Deviation from trimmed Internal oscillator 12.8 MHz, fixed voltage, fixed temp 12.8 MHz, VDD 10%, 0 to 70C 12.8 MHz, VDD 10%, -40 to 125C Crystal frequency, XTALCLK(1)
ACCINT fOSCXCLK fRCCLK fOSCXCLK CL C1 C2 RB REXT
%
MHz MHz MHz pF -- -- M --
External RC oscillator frequency, RCCLK (1) External clock reference frequency(1) (4) Crystal load capacitance(5) Crystal fixed capacitance(3) Crystal tuning capacitance(3) Feedback bias resistor RC oscillator external resistor Crystal series damping resistor fOSCXCLK = 1 MHz fOSCXCLK = 4 MHz fOSCXCLK = > 8 MHz
RS
-- -- --
10 5 0
-- -- --
k
1. Bus frequency, fOP, is oscillator frequency divided by 4. 2. Deviation values assumes trimming @25C and midpoint of voltage range. 3. Values are based on characterization results, not tested in production. 4. No more than 10% duty cycle deviation from 50% 5. Consult crystal vendor data sheet
12 3 V 25C 10
RCCLK (MHz)
8
RC FREQUENCY, f
6
4
2
0 0 10 20 30 R EXT (k ) 40 50 60
Figure 16-8. RC versus Frequency (3 Volts @ 25C)
MC68HC908QY/QT Family Data Sheet, Rev. 5 158 Freescale Semiconductor
Supply Current Characteristics
16.13 Supply Current Characteristics
Characteristic(1) Run Mode VDD supply current(3) Wait Mode VDD supply current(4) Stop Mode VDD supply current(5) -40 to 85C -40 to 105C -40 to 125C 25C with auto wakeup enabled Incremental current with LVI enabled at 25C Stop Mode VDD supply current(5) -40 to 85C -40 to 105C -40 to 125C 25C with auto wakeup enabled Incremental current with LVI enabled at 25C Voltage 5.0 3.0 5.0 3.0 Bus Frequency (MHz) 3.2 3.2 3.2 3.2 Symbol RIDD WIDD Typ(2) 6.0 2.5 1.0 0.67 0.04 -- -- 7 125 0.02 -- -- 5 100 Max 7.0 3.2 1.5 1.0 1.0 2.0 5.0 -- -- 0.5 1.0 4.0 -- -- Unit
mA mA mA
5.0
SIDD
A
3.0
SIDD
A
1. VSS = 0 Vdc, TA = TL to TH, unless otherwise noted. 2. Typical values reflect average measurements at 25C only. 3. Run (operating) IDD measured using trimmed internal oscillator, ADC off, all other modules enabled. All pins configured as inputs and tied to 0.2 V from rail. 4. Wait IDD measured using trimmed internal oscillator, ADC off, all other modules enabled. All pins configured as inputs and tied to 0.2 V from rail. 5. Stop IDD measured with all pins tied to 0.2 V or less from rail. No dc loads. On the 8-pin versions, port B is configured as inputs with pullups enabled.
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 159
Electrical Specifications
14 12 10 IDD (mA) 8 6 4 2 0 0 1 2 3 4 5 6 7 Bus Frequency (MHz) Crystal w/o ADC Crystal w/ ADC Internal Osc w/o ADC Internal Osc w/ ADC
Figure 16-9. Typical 5-Volt Run Current versus Bus Frequency (25C)
4
3 Crystal w/o ADC IDD (mA) 2 Crystal w/ ADC Internal Osc w/o ADC 1 Internal Osc w/ ADC
0 0 1 2 3 4 5 Bus Frequency (MHz)
Figure 16-10. Typical 3-Volt Run Current versus Bus Frequency (25C)
MC68HC908QY/QT Family Data Sheet, Rev. 5 160 Freescale Semiconductor
Analog-to-Digital Converter Characteristics
16.14 Analog-to-Digital Converter Characteristics
Characteristic Supply voltage Input voltages Resolution (1 LSB) Absolute accuracy (Total unadjusted error) ADC internal clock Conversion range Power-up time Conversion time Sample time(1) Zero input reading(2) Full-scale reading(3) Input capacitance Input leakage(3) ADC supply current VDD = 3 V VDD = 5 V Symbol VDDAD VADIN RES ETUE fADIC VAIN tADPU tADC tADS ZADI FADI CADI IIL IADAD Min 2.7 (VDD min) VSS 10.5 -- 0.5 VSS 16 16 5 00 FE -- -- Max 5.5 (VDD max) VDD 21.5 1.5 1.048 VDD -- 17 -- 01 FF 8 1 Unit V V mV LSB MHz V tADIC cycles tADIC cycles tADIC cycles Hex Hex pF A mA mA Comments -- -- -- Includes quantization tADIC = 1/fADIC, tested only at 1 MHz -- tADIC = 1/fADIC tADIC = 1/fADIC tADIC = 1/fADIC VIN = VSS VIN = VDD Not tested --
Typical = 0.45 Typical = 0.65
Enabled Enabled
1. Source impedances greater than 10 k adversely affect internal RC charging time during input sampling. 2. Zero-input/full-scale reading requires sufficient decoupling measures for accurate conversions. 3. The external system error caused by input leakage current is approximately equal to the product of R source and input current.
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 161
Electrical Specifications
16.15 Timer Interface Module Characteristics
Characteristic Timer input capture pulse width Timer input capture period Timer input clock pulse width Symbol tTH, tTL tTLTL tTCL, tTCH Min 2 Note(1) tcyc + 5 Max -- -- -- Unit tcyc tcyc ns
1. The minimum period is the number of cycles it takes to execute the interrupt service routine plus 1 tcyc.
tTLTL tTH INPUT CAPTURE RISING EDGE
tTLTL tTL INPUT CAPTURE FALLING EDGE
tTLTL tTH INPUT CAPTURE BOTH EDGES tTL
tTCH TCLK tTCL
Figure 16-11. Timer Input Timing
MC68HC908QY/QT Family Data Sheet, Rev. 5 162 Freescale Semiconductor
Memory Characteristics
16.16 Memory Characteristics
Characteristic RAM data retention voltage FLASH program bus clock frequency FLASH read bus clock frequency FLASH page erase time <1 k cycles >1 k cycles FLASH mass erase time FLASH PGM/ERASE to HVEN setup time FLASH high-voltage hold time FLASH high-voltage hold time (mass erase) FLASH program hold time FLASH program time FLASH return to read time FLASH cumulative program HV period FLASH endurance(4) FLASH data retention time(5) Symbol VRDR -- fRead(1) tErase tMErase tNVS tNVH tNVHL tPGS tPROG tRCV(2) tHV(3) -- -- Min 1.3 1 0 Typ -- -- -- Max -- -- 8M Unit V MHz Hz
0.9 3.6 4 10 5 100 5 30 1 -- 10 k 15
1 4 -- -- -- -- -- -- -- -- 100 k 100
1.1 5.5 -- -- -- -- -- 40 -- 4 -- --
ms
ms s s s s s s ms Cycles Years
1. fRead is defined as the frequency range for which the FLASH memory can be read. 2. tRCV is defined as the time it needs before the FLASH can be read after turning off the high voltage charge pump, by clearing HVEN to 0. 3. tHV is defined as the cumulative high voltage programming time to the same row before next erase. tHV must satisfy this condition: tNVS + tNVH + tPGS + (tPROG x 32) tHV maximum. 4. Typical endurance was evaluated for this product family. For additional information on how Freescale defines Typical Endurance, please refer to Engineering Bulletin EB619. 5. Typical data retention values are based on intrinsic capability of the technology measured at high temperature and de-rated to 25C using the Arrhenius equation. For additional information on how Freescale defines Typical Data Retention, please refer to Engineering Bulletin EB618.
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 163
Electrical Specifications
MC68HC908QY/QT Family Data Sheet, Rev. 5 164 Freescale Semiconductor
Chapter 17 Ordering Information and Mechanical Specifications
17.1 Introduction
This section contains order numbers for the MC68HC908QY1, MC68HC908QY2, MC68HC908QY4, MC68HC908QT1, MC68HC908QT2, and MC69HC908QT4. Dimensions are given for: * 8-pin plastic dual in-line package (PDIP) * 8-pin small outline integrated circuit (SOIC) package * 8-pin dual flat no lead (DFN) package * 16-pin PDIP * 16-pin SOIC * 16-pin thin shrink small outline package (TSSOP)
17.2 MC Order Numbers
Table 17-1. MC Order Numbers
MC Order Number MC908QY1 MC908QY2 MC908QY4 MC908QT1 MC908QT2 MC908QT4 ADC -- Yes Yes -- Yes Yes FLASH Memory 1536 bytes 1536 bytes 4096 bytes 1536 bytes 1536 bytes 4096 bytes Package 16-pins PDIP, SOIC, and TSSOP 8-pins PDIP, SOIC, and DFN
Temperature and package designators: C = -40C to +85C V = -40C to +105C M = -40C to +125C P = Plastic dual in-line package (PDIP) DW = Small outline integrated circuit package (SOIC) DT = Thin shrink small outline package (TSSOP) FQ = Dual flat no lead (DFN)
MC908QY1XXXE
FAMILY Pb FREE PACKAGE DESIGNATOR TEMPERATURE RANGE
Figure 17-1. Device Numbering System
17.3 Package Dimensions
Refer to the following pages for detailed package dimensions.
MC68HC908QY/QT Family Data Sheet, Rev. 5 Freescale Semiconductor 165
How to Reach Us:
Home Page: www.freescale.com E-mail: support@freescale.com USA/Europe or Locations Not Listed: Freescale Semiconductor Technical Information Center, CH370 1300 N. Alma School Road Chandler, Arizona 85224 +1-800-521-6274 or +1-480-768-2130 support@freescale.com Europe, Middle East, and Africa: Freescale Halbleiter Deutschland GmbH Technical Information Center Schatzbogen 7 81829 Muenchen, Germany +44 1296 380 456 (English) +46 8 52200080 (English) +49 89 92103 559 (German) +33 1 69 35 48 48 (French) support@freescale.com Japan: Freescale Semiconductor Japan Ltd. Headquarters ARCO Tower 15F 1-8-1, Shimo-Meguro, Meguro-ku, Tokyo 153-0064 Japan 0120 191014 or +81 3 5437 9125 support.japan@freescale.com Asia/Pacific: Freescale Semiconductor Hong Kong Ltd. Technical Information Center 2 Dai King Street Tai Po Industrial Estate Tai Po, N.T., Hong Kong +800 2666 8080 support.asia@freescale.com For Literature Requests Only: Freescale Semiconductor Literature Distribution Center P.O. Box 5405 Denver, Colorado 80217 1-800-441-2447 or 303-675-2140 Fax: 303-675-2150 LDCForFreescaleSemiconductor@hibbertgroup.com
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MC68HC908QY4 Rev. 5, 06/2005

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