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april 2005 1/154 rev. 1 st7232a 8-bit mcu with 8k flash/rom, adc, 4 timers, spi, sci interface memories ? 8k dual voltage high density flash (hdflash) or rom with read -out protection capability. in- application programmin g and in-circuit pro- gramming for hdflash devices ? 384 bytes ram ? hdflash endurance: 100 cycles, data reten- tion: 20 years at 55c clock, reset and supply management ? clock sources: crystal/ceramic resonator os- cillators and bypass for external clock ? pll for 2x frequency multiplication ? four power saving modes: halt, active-halt, wait and slow interrupt management ? nested interrupt controller ? 14 interrupt vectors plus trap and reset ? 6 external interrupt lines (on 4 vectors) up to 32 i/o ports ? 24 multifunctional bi directional i/o lines ? 17 alternate function lines ? 10 high sink outputs 4timers ? main clock controller with: real time base, beep and clock-out capabilities ? configurable watchdog timer ? two 16-bit timers with: 2 input captures, 2 out- putcompares, pwm and pulse generator modes 2 communications interfaces ? spi synchronous serial interface ? sci asynchronous serial interface 1 analog peripheral (low current coupling) ? 10-bit adc with up to 12 robust input ports instruction set ? 8-bit data manipulation ? 63 basic instructions ? 17 main addressing modes ? 8 x 8 unsigned multiply instruction development tools ? full hardware/software development package ? in-circuit testing capability device summary tqfp32 7 x 7 sdip32 400mil features st72f32a k2 st7232ak1 st7232ak2 program memory - bytes flash 8k rom 4k rom 8k ram (stack) - bytes 384 (256) operating voltage 3.8v to 5.5v temp. range up to -40c to +85c package tqfp32 7x7 , sdip32 400mils 1
table of contents 154 2/154 1 introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 2 pin description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 3 register & memory map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1 4 flash program memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 4.1 introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 5 4.2 main features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 5 4.3 structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 4.3.1 read-out protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 4.4 icc interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 4.5 icp (in-circuit programming) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 4.6 iap (in-application programming) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 4.7 related documentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 4.7.1 register description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 5 central processing unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 5.1 introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 8 5.2 main features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 8 5.3 cpu registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 6 supply, reset and clock management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 6.1 phase locked loop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 6.2 multi-oscillator (mo) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 6.3 reset sequence manager (rsm) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 6.3.1 introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 6.3.2 asynchronous external reset pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 6.3.3 external power-on reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 6.3.4 internal watchdog reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 6.4 system integrity management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 6.4.1 register description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 7 interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 7.1 introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 6 7.2 masking and processing flow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 7.3 interrupts and low power modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 7.4 concurrent & nested management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 7.5 interrupt register description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 7.6 external interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 7.6.1 i/o port interrupt sensitivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 7.7 external interrupt control regi ster (eicr) . . . . . . . . . . . . . . . . . . . . . . . 33 8 power saving modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 8.1 introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 5 8.2 slow mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 8.3 wait mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 8.4 active-halt and halt modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 8.4.1 active-halt mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 8.4.2 halt mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 2
table of contents 154 3/154 9 i/o ports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 9.1 introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 0 9.2 functional description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 9.2.1 input modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 0 9.2.2 output modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 9.2.3 alternate functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 9.3 i/o port implementation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 9.4 low power modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 9.5 interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 9.5.1 i/o port implementation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 10 on-chip peripherals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 10.1 watchdog timer (wdg) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 10.1.1 introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 10.1.2 main features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 6 10.1.3 functional description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 10.1.4 how to program the watchdog timeout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 10.1.5 low power modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 10.1.6 hardware watchdog option . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 10.1.7 using halt mode with the wdg (wdghalt option) . . . . . . . . . . . . . . . . . . . . . . . 49 10.1.8 interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 10.1.9 register description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 10.2 main clock controller with real time clock and beeper (mcc/rtc) . 51 10.2.1 programmable cpu clock prescaler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 10.2.2 clock-out capability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 10.2.3 real time clock timer (rtc) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 10.2.4 beeper . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 10.2.5 low power modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 10.2.6 interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 10.2.7 register description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 10.3 16-bit timer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54 10.3.1 introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54 10.3.2 main features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 4 10.3.3 functional description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54 10.3.4 low power modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66 10.3.5 interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66 10.3.6 summary of timer modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66 10.3.7 register description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67 10.4 serial peripheral interface (spi) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74 10.4.1 introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74 10.4.2 main features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 4 10.4.3 general description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74 10.4.4 clock phase and clock polarity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78 10.4.5 error flags . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79 10.4.6 low power modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81 10.4.7 interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81 10.4.8 register description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82 10.5 serial communications interface (sci) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85 1
table of contents 154 4/154 10.5.1 introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85 10.5.2 main features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 5 10.5.3 general description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85 10.5.4 functional description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87 10.5.5 low power modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94 10.5.6 interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94 10.5.7 register description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95 10.6 10-bit a/d converter (adc) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101 10.6.1 introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101 10.6.2 main features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101 10.6.3 functional description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102 10.6.4 low power modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102 10.6.5 interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102 10.6.6 register description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103 11 instruction set . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105 11.1 cpu addressing modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105 11.1.1 inherent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106 11.1.2 immediate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 06 11.1.3 direct . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106 11.1.4 indexed (no offset, short, long) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106 11.1.5 indirect (short, long) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106 11.1.6 indirect indexed (short, long) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107 11.1.7 relative mode (direct, indirect) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107 11.2 instruction groups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108 12 electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111 12.1 parameter conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111 12.1.1 minimum and maximum values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111 12.1.2 typical values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 1 12.1.3 typical curves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 1 12.1.4 loading capacitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111 12.1.5 pin input voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111 12.2 absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112 12.2.1 voltage characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112 12.2.2 current characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112 12.2.3 thermal characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113 12.3 operating conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113 12.3.1 operating conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113 12.4 supply current characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114 12.4.1 current consumption . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114 12.4.2 supply and clock managers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116 12.4.3 on-chip peripherals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117 12.5 clock and timing characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118 12.5.1 general timings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118 12.5.2 external clock source . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118 12.5.3 crystal and ceramic re sonator oscillators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119 12.5.4 pll characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121 12.6 memory characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122 1
table of contents 154 5/154 12.6.1 ram and hardware registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122 12.6.2 flash memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122 12.7 emc characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123 12.7.1 functional ems (electro magnetic susceptibility) . . . . . . . . . . . . . . . . . . . . . . . . 123 12.7.2 electro magnetic interference (emi) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124 12.7.3 absolute maximum ratings (electrical sensitivity) . . . . . . . . . . . . . . . . . . . . . . . . 125 12.8 i/o port pin characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126 12.8.1 general characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126 12.8.2 output driving current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127 12.9 control pin characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129 12.9.1 asynchronous reset pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129 12.9.2 iccsel/vpp pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131 12.10 timer peripheral characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132 12.10.116-bit timer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132 12.11 communication interface characteristics . . . . . . . . . . . . . . . . . . . . . . . . 133 12.11.1spi - serial peripheral interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133 12.12 10-bit adc characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135 12.12.1analog power supply and reference pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137 12.12.2general pcb design guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137 12.12.3adc accuracy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138 13 package characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139 13.1 package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139 13.2 thermal characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140 13.3 soldering information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141 14 st7232a device configuration and ordering information . . . . . . . . . . . . . . . 142 14.1 flash option bytes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142 14.2 rom device ordering information and transfer of customer code 144 14.3 version-specific sales conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146 14.4 flash device ordering information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146 14.5 development tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147 14.5.1 socket and emulator adapter information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148 14.6 st7 application notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149 15 known limitations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151 15.1 all flash and rom devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151 15.1.1 safe connection of osc1/osc2 pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151 15.1.2 unexpected reset fetch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151 15.1.3 clearing active interrupts outside interrupt routine . . . . . . . . . . . . . . . . . . . . . . . . 151 15.1.4 16-bit timer pwm mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151 15.1.5 sci wrong break duration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151 15.1.6 39-pulse icc entry mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152 15.2 rom devices only . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152 15.2.1 i/o port a and f configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152 15.2.2 external clock source with pll . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152 16 revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153 1
table of contents 154 6/154 to obtain the most recent version of this datasheet, please check at www.st.com>produc ts>technical literature>datasheet. please also pay special attention to the section ?known limitations? on page 151 . 1
st7232a 7/154 1 introduction the st72f32a and st7232a devices are mem- bers of the st7 microcontroller family designed for the 5v operating range. the 32-pin devices are designed for mid-range ap- plications all devices are based on a common industry- standard 8-bit core, featuring an enhanced instruc- tion set and are available with flash or rom pro- gram memory. under software control, all devices can be placed in wait, slow, active-halt or halt mode, reducing power consumption when the application is in idle or stand-by state. the enhanced instruction set and addressing modes of the st7 offer bo th power and flexibility to software developers, enabling the design of highly efficient and compact application code. in addition to standard 8-bit data management, all st7 micro- controllers feature true bit manipulation, 8x8 un- signed multiplication and indirect addressing modes. figure 1. device block diagram 8-bit core alu address and data bus osc1 v pp control program (8k bytes) v dd reset port f timer a beep port a ram (384 bytes) port c 10-bit adc v aref v ssa port b port e sci timer b port d spi v ss watchdog osc osc2 memory mcc/rtc/beep 3
st7232a 8/154 2 pin description figure 2. 32-pin sdip package pinout figure 3. 32-pin tqfp 7x7 package pinout 28 27 26 25 24 23 22 21 20 19 18 17 16 15 1 2 3 4 5 6 7 8 9 10 11 12 13 14 29 30 31 32 (hs) pb4 ain0 / pd0 ain14 / mosi / pc5 iccdata/ miso / pc4 icap1_b / (hs) pc3 icap2_b / (hs) pc2 ain13 / ocmp1_b / pc1 ain12 / ocmp2_b / pc0 extclk_a / (hs) pf7 beep / (hs) pf1 mco / ain8 / pf0 v ssa v aref ain1 / pd1 icap1_a / (hs) pf6 ocmp1_a / ain10 / pf4 pb3 pb0 pc6 / sck / iccclk pc7 / ss / ain15 pa3 (hs) pa4 (hs) pa6 (hs) pa7 (hs) v pp / iccsel osc2 osc1 v dd _2 pe0 / tdo pe1 / rdi v ss _2 reset ei0 ei3 ei2 ei1 eix associated external interrupt vector (hs) 20ma high sink capability iccdata / miso / pc4 ain14 / mosi / pc5 iccclk / sck / pc6 ain15 / ss / pc7 (hs) pa3 ain13 / ocmp1_b / pc1 icap2_b / (hs) pc2 icap1_b / (hs) pc3 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 9 10111213141516 1 2 3 4 5 6 7 8 ei1 ei3 ei0 ocmp1_a / ain10 / pf4 icap1_a / (hs) pf6 extclk_a / (hs) pf7 ain12 / ocmp2_b / pc0 v aref v ssa mco / ain8 / pf0 beep / (hs) pf1 v pp / iccsel pa7 (hs) pa6 (hs) pa4 (hs) osc1 osc2 v ss _2 reset pb0 pe1 / rdi pe0 / tdo v dd _2 pd1 / ain1 pd0 / ain0 pb4 (hs) pb3 ei2 eix associated external interrupt vector (hs) 20ma high sink capability
st7232a 9/154 pin description (cont?d) for external pin connection guidelines, refer to see ?electrical characteristics? on page 111. legend / abbreviations for table 1 : type: i = input, o = output, s = supply input level: a = dedicated analog input in/output level: c = cmos 0.3v dd /0.7v dd c t = cmos 0.3v dd /0.7v dd with input trigger output level: hs = 20ma high sink (on n-buffer only) port and control configuration: ? input: float = floating, wpu = weak pull-up, int = interrupt 1) , ana = analog ports ? output: od = open drain 2) , pp = push-pull refer to ?i/o ports? on page 40 for more details on the software configuration of the i/o ports. the reset configuration of ea ch pin is shown in bold. th is configuration is valid as long as the device is in reset state. table 1. device pin description pin n pin name type level port main function (after reset) alternate function tqfp32 sdip32 input output input output float wpu int ana od pp 14v aref s analog reference voltage for adc 25v ssa s analog ground voltage 3 6 pf0/mco/ain8 i/o c t x ei1 x x x port f0 main clock out (f osc /2) adc analog input 8 4 7 pf1 (hs)/beep i/o c t hs x ei1 x x port f1 beep signal output 58 pf4/ocmp1_a/ ain10 i/o c t x xxxxport f4 timer a out- put com- pare 1 adc analog input 10 6 9 pf6 (hs)/icap1_a i/o c t hs x x x x port f6 timer a input capture 1 710 pf7 (hs)/ extclk_a i/o c t hs x xxxport f7 timer a external clock source 811 pc0/ocmp2_b/ ain12 i/o c t x xxxxport c0 timer b out- put com- pare 2 adc analog input 12 912 pc1/ocmp1_b/ ain13 i/o c t x xxxxport c1 timer b out- put com- pare 1 adc analog input 13 10 13 pc2 (hs)/icap2_b i/o c t hs x x x x port c2 timer b input capture 2 11 14 pc3 (hs)/icap1_b i/o c t hs x x x x port c3 timer b input capture 1 12 15 pc4/miso/iccda- ta i/o c t x xxxport c4 spi master in / slave out data icc data in- put 13 16 pc5/mosi/ain14 i/o c t x xxxxport c5 spi master out / slave in data adc analog input 14 14 17 pc6/sck/iccclk i/o c t x xxxport c6 spi serial clock icc clock output 1
st7232a 10/154 notes : 1. in the interrupt input column, ?eix? defines the associated external interrupt vector. if the weak pull-up column (wpu) is merged with the interrupt column (int), then the i/o configuration is pull-up interrupt input, else the configuration is floating interrupt input. 2. in the open drain output column, ?t? defines a true open drain i/o (p-buffer and protection diode to v dd are not implemented). see see ?i/o ports? on page 40. and section 12.8 i/o port pin character- istics for more details. 3. osc1 and osc2 pins connect a crystal/ceramic reso nator, or an external source to the on-chip oscil- lator; see section 1 introduction and section 12.5 clock and timing characteristics for more details. 4. on the chip, each i/o port has 8 pads. pads that are not bonded to external pins are in input pull-up con- figuration after reset. the configuration of these pads must be kept at reset state to avoid added current consumption. 5. for details refer to section 12.8.1 on page 126 15 18 pc7/ss /ain15 i/o c t x xxxxport c7 spi slave select (ac- tive low) adc analog input 15 16 19 pa3 (hs) i/o c t hs x ei0 x x port a3 17 20 pa4 (hs) i/o c t hs x xxxport a4 18 21 pa6 (hs) i/o c t hs x tport a6 1) 19 22 pa7 (hs) i/o c t hs x tport a7 1) 20 23 v pp /iccsel i must be tied low. in the flash pro- gramming mode, this pin acts as the programming voltage input v pp . see section 12.9.2 for more details. high voltage must not be applied to rom devices. 21 24 reset i/o c t top priority non maskable interrupt. 22 25 v ss_2 s digital ground voltage 23 26 osc2 o resonator oscill ator inverter output 24 27 osc1 i external clock input or resonator os- cillator inverter input 25 28 v dd_2 s digital main supply voltage 26 29 pe0/tdo i/o c t x x x x port e0 sci transmit data out 27 30 pe1/rdi i/o c t x x x x port e1 sci receive data in 28 31 pb0 i/o c t x ei2 x x port b0 caution: negative cur- rent injection not al- lowed on this pin 5) 29 32 pb3 i/o c t x ei2 x x port b3 30 1 pb4 (hs) i/o c t hs x ei3 x x port b4 31 2 pd0/ain0 i/o c t x x x x x port d0 adc analog input 0 32 3 pd1/ain1 i/o c t x x x x x port d1 adc analog input 1 pin n pin name type level port main function (after reset) alternate function tqfp32 sdip32 input output input output float wpu int ana od pp 1
st7232a 11/154 3 register & memory map as shown in figure 4 , the mcu is capable of ad- dressing 64k bytes of memories and i/o registers. the available memory locations consist of 128 bytes of register locations, up to 384 bytes of ram and up to 8 kbytes of user program memory. the ram space includes up to 256 bytes for the stack from 0100h to 01ffh. the highest address bytes contain the user reset and interrupt vectors. important: memory locations marked as ?re- served? must never be accessed. accessing a re- seved area can have unpredictable effects on the device. figure 4. memory map 0000h ram program memory ( 8k) interrupt & reset vectors hw registers 0080h 007fh (see table 2 ) e000h ffdfh ffe0h ffffh (see table 8 ) 0480h reserved 047fh short addressing ram (zero page) 256 bytes stack reserved 0100h 01ffh 027fh 0080h 0200h 00ffh or 047fh (384 bytes) 1
st7232a 12/154 table 2. hardware register map address block register label register name reset status remarks 0000h 0001h 0002h port a 2) padr paddr paor port a data register port a data direction register port a option register 00h 1) 00h 00h r/w r/w r/w 0003h 0004h 0005h port b 2) pbdr pbddr pbor port b data register port b data direction register port b option register 00h 1) 00h 00h r/w r/w r/w 0006h 0007h 0008h port c pcdr pcddr pcor port c data register port c data direction register port c option register 00h 1) 00h 00h r/w r/w r/w 0009h 000ah 000bh port d 2) pdadr pdddr pdor port d data register port d data direction register port d option register 00h 1) 00h 00h r/w r/w r/w 000ch 000dh 000eh port e 2) pedr peddr peor port e data register port e data direction register port e option register 00h 1) 00h 00h r/w r/w 2) r/w 2) 000fh 0010h 0011h port f 2) pfdr pfddr pfor port f data register port f data direction register port f option register 00h 1) 00h 00h r/w r/w r/w 0012h to 0020h reserved area (15 bytes) 0021h 0022h 0023h spi spidr spicr spicsr spi data i/o register spi control register spi control/status register xxh 0xh 00h r/w r/w r/w 0024h 0025h 0026h 0027h itc ispr0 ispr1 ispr2 ispr3 interrupt software pr iority register 0 interrupt software pr iority register 1 interrupt software pr iority register 2 interrupt software pr iority register 3 ffh ffh ffh ffh r/w r/w r/w r/w 0028h eicr external interrupt control register 00h r/w 0029h flash fcsr flash contro l/status register 00h r/w 002ah watchdog wdgcr watchdog control register 7fh r/w 002bh reserved area (1 byte) 002ch 002dh mcc mccsr mccbcr main clock control / status register main clock controller: beep control register 00h 00h r/w r/w 002eh to 0030h reserved area (3 bytes) 1
st7232a 13/154 0031h 0032h 0033h 0034h 0035h 0036h 0037h 0038h 0039h 003ah 003bh 003ch 003dh 003eh 003fh timer a tacr2 tacr1 tacsr taic1hr taic1lr taoc1hr taoc1lr tachr taclr taachr taaclr taic2hr taic2lr taoc2hr taoc2lr timer a control register 2 timer a control register 1 timer a control/status register timer a input capture 1 high register timer a input capture 1 low register timer a output compare 1 high register timer a output compare 1 low register timer a counter high register timer a counter low register timer a alternate c ounter high register timer a alternate c ounter low register timer a input capture 2 high register timer a input capture 2 low register timer a output compare 2 high register timer a output compare 2 low register 00h 00h xxxx x0xxb xxh xxh 80h 00h ffh fch ffh fch xxh xxh 80h 00h r/w r/w r/w read only read only r/w r/w read only read only read only read only read only read only r/w r/w 0040h reserved area (1 byte) 0041h 0042h 0043h 0044h 0045h 0046h 0047h 0048h 0049h 004ah 004bh 004ch 004dh 004eh 004fh timer b tbcr2 tbcr1 tbcsr tbic1hr tbic1lr tboc1hr tboc1lr tbchr tbclr tbachr tbaclr tbic2hr tbic2lr tboc2hr tboc2lr timer b control register 2 timer b control register 1 timer b control/status register timer b input capture 1 high register timer b input capture 1 low register timer b output compare 1 high register timer b output compare 1 low register timer b counter high register timer b counter low register timer b alternate c ounter high register timer b alternate c ounter low register timer b input capture 2 high register timer b input capture 2 low register timer b output compare 2 high register timer b output compare 2 low register 00h 00h xxxx x0xxb xxh xxh 80h 00h ffh fch ffh fch xxh xxh 80h 00h r/w r/w r/w read only read only r/w r/w read only read only read only read only read only read only r/w r/w 0050h 0051h 0052h 0053h 0054h 0055h 0056h 0057h sci scisr scidr scibrr scicr1 scicr2 scierpr scietpr sci status register sci data register sci baud rate register sci control register 1 sci control register 2 sci extended receive prescaler register reserved area sci extended transmit prescaler register c0h xxh 00h x000 0000h 00h 00h --- 00h read only r/w r/w r/w r/w r/w r/w 0058h to 006fh reserved area (24 bytes) 0070h 0071h 0072h adc adccsr adcdrh adcdrl control/status register data high register data low register 00h 00h 00h r/w read only read only 0073h 007fh reserved area (13 bytes) address block register label register name reset status remarks 1
st7232a 14/154 legend : x=undefined, r/w=read/write notes : 1. the contents of the i/o port dr registers are readable only in output configuration. in input configura- tion, the values of the i/o pins are retur ned instead of the dr register contents. 2. the bits associated with unavailable pins must always keep their reset value. 1
st7232a 15/154 4 flash program memory 4.1 introduction the st7 dual voltage high density flash (hdflash) is a non-volatile memory that can be electrically erased as a single block or by individu- al sectors and programmed on a byte-by-byte ba- sis using an external v pp supply. the hdflash devices can be programmed and erased off-board (plugged in a programming tool) or on-board using icp (in-circuit programming) or iap (in-application programming). the array matrix organisation allows each sector to be erased and reprogrammed without affecting other sectors. 4.2 main features three flash programming modes: ? insertion in a programming tool. in this mode, all sectors including option bytes can be pro- grammed or erased. ? icp (in-circuit programming). in this mode, all sectors including option bytes can be pro- grammed or erased without removing the de- vice from the application board. ? iap (in-application programming) in this mode, all sectors except sector 0, can be pro- grammed or erased without removing the de- vice from the application board and while the application is running. ict (in-circuit testing) for downloading and executing user application test patterns in ram read-out protection register access securi ty system (rass) to prevent accidental programming or erasing 4.3 structure the flash memory is organised in sectors and can be used for both code and data storage. depending on the overall flash memory size in the microcontroller device, there are up to three user sectors (see table 3 ). each of these sectors can be erased independently to avoid unnecessary erasing of the whole flash memory when only a partial erasing is required. the first two sectors have a fixed size of 4 kbytes (see figure 5 ). they are mapped in the upper part of the st7 addressing space so the reset and in- terrupt vectors are located in sector 0 (f000h- ffffh). table 3. sectors available in flash devices 4.3.1 read-out protection read-out protection, when selected, provides a protection against program memory content ex- traction and against write access to flash memo- ry. even if no protection can be considered as to- tally unbreakable, the feature provides a very high level of protection for a general purpose microcon- troller. in flash devices, this protection is removed by re- programming the option. in this case, the entire program memory is first automatically erased. read-out protection selection depends on the de- vice type: ? in flash devices it is enabled and removed through the fmp_r bit in the option byte. ? in rom devices it is enabled by mask option specified in the option list. figure 5. memory map and sector address flash size (bytes) available sectors 4k sector 0 8k sectors 0,1 > 8k sectors 0,1, 2 4 kbytes 4 kbytes 2kbytes sector 1 sector 0 16 kbytes sector 2 8k 16k 32k 60k flash ffffh efffh dfffh 3fffh 7fffh 1000h 24 kbytes memory size 8kbytes 40 kbytes 52 kbytes 9fffh bfffh d7ffh 4k 10k 24k 48k 1
st7232a 16/154 flash program memory (cont?d) 4.4 icc interface icc needs a minimum of 4 and up to 6 pins to be connected to the programming tool (see figure 6 ). these pins are: ? reset : device reset ?v ss : device power supply ground ? iccclk: icc output serial clock pin ? iccdata: icc input/output serial data pin ? iccsel/v pp : programming voltage ? osc1(or oscin): main clock input for exter- nal source (optional) ?v dd : application board power supply (option- al, see figure 6 , note 3) figure 6. typical icc interface notes: 1. if the iccclk or iccdata pins are only used as outputs in the application, no signal isolation is necessary. as soon as the programming tool is plugged to the board, even if an icc session is not in progress, the iccclk and iccdata pins are not available for the application. if they are used as inputs by the application, isolation such as a serial resistor has to implemented in case another de- vice forces the signal. refer to the programming tool documentation for recommended resistor val- ues. 2. during the icc session, the programming tool must control the reset pin. this can lead to con- flicts between the programming tool and the appli- cation reset circuit if it drives more than 5ma at high level (push pull output or pull-up resistor<1k). a schottky diode can be used to isolate the appli- cation reset circuit in this case. when using a classical rc network with r>1k or a reset man- agement ic with open drain output and pull-up re- sistor>1k, no additional components are needed. in all cases the user must ensure that no external reset is generated by the application during the icc session. 3. the use of pin 7 of the icc connector depends on the programming tool architecture. this pin must be connected when using most st program- ming tools (it is used to monitor the application power supply). please refer to the programming tool manual. 4. pin 9 has to be connected to the osc1 or os- cin pin of the st7 when the clock is not available in the application or if the selected clock option is not programmed in the option byte. st7 devices with multi-oscillator ca pability need to have osc2 grounded in this case. caution: external clock icc entry mode is man- datory. pin 9 must be connected to the osc1 or oscin pin of the st7 and osc2 must be ground- ed. icc connector iccdata iccclk reset v dd he10 connector type application power supply 1 2 4 6 8 10 97 5 3 programming tool icc connector application board icc cable (see note 3) 10k ? v ss iccsel/vpp st7 c l2 c l1 osc1 osc2 optional see note 1 see note 2 application reset source application i/o (see note 4) in some cases 1
st7232a 17/154 flash program memory (cont?d) 4.5 icp (in-circuit programming) to perform icp the microcontroller must be switched to icc (in-circu it communication) mode by an external controller or programming tool. depending on the icp code downloaded in ram, flash memory programming can be fully custom- ized (number of bytes to program, program loca- tions, or selection serial communication interface for downloading). when using an stmicroelectronics or third-party programming tool that supports icp and the spe- cific microcontroller device, the user needs only to implement the icp hardware interface on the ap- plication board (see figure 6 ). for more details on the pin locations, refer to the device pinout de- scription. 4.6 iap (in-application programming) this mode uses a bootloader program previously stored in sector 0 by the user (in icp mode or by plugging the device in a programming tool). this mode is fully controlled by user software. this allows it to be adapted to the user application, (us- er-defined strategy for entering programming mode, choice of communications protocol used to fetch the data to be stored, etc.). for example, it is possible to download code from the spi, sci, usb or can interface and program it in the flash. iap mode can be used to program any of the flash sectors except sector 0, which is write/erase pro- tected to allow recovery in case errors occur dur- ing the programming operation. 4.7 related documentation for details on flash programming and icc proto- col, refer to the st7 flash programming refer- ence manual and to the st7 icc protocol refer- ence manual . 4.7.1 register description flash control/status register (fcsr) read/write reset value: 0000 0000 (00h) this register is reserved for use by programming tool software. it controls the flash programming and erasing operations. table 4. flash control/status re gister address and reset value 70 00000000 address (hex.) register label 76543210 0029h fcsr reset value00000000 1
st7232a 18/154 5 central processing unit 5.1 introduction this cpu has a full 8-bit architecture and contains six internal registers allowing efficient 8-bit data manipulation. 5.2 main features enable executing 63 basic instructions fast 8-bit by 8-bit multiply 17 main addressing modes (with indirect addressing mode) two 8-bit index registers 16-bit stack pointer low power halt and wait modes priority maskable hardware interrupts non-maskable software/hardware interrupts 5.3 cpu registers the 6 cpu registers shown in figure 7 are not present in the memory mapping and are accessed by specific instructions. accumulator (a) the accumulator is an 8-bit general purpose reg- ister used to hold operands and the results of the arithmetic and logic calculations and to manipulate data. index registers (x and y) these 8-bit registers are used to create effective addresses or as temporary storage areas for data manipulation. (the cross-assembler generates a precede instruction (pre) to indicate that the fol- lowing instruction refers to the y register.) the y register is not affected by the interrupt auto- matic procedures. program counter (pc) the program counter is a 16-bit register containing the address of the next instruction to be executed by the cpu. it is made of two 8-bit registers pcl (program counter low which is the lsb) and pch (program counter high which is the msb). figure 7. cpu registers accumulator x index register y index register stack pointer condition code register program counter 70 1c 1i1hi0nz reset value = reset vector @ fffeh-ffffh 70 70 70 0 7 15 8 pch pcl 15 8 70 reset value = stack higher address reset value = 1x 11x1xx reset value = xxh reset value = xxh reset value = xxh x = undefined value 1
st7232a 19/154 central processing unit (cont?d) condition code register (cc) read/write reset value: 111x1xxx the 8-bit condition code register contains the in- terrupt masks and four flags representative of the result of the instruction just executed. this register can also be handled by the push and pop in- structions. these bits can be individually tested and/or con- trolled by specific instructions. arithmetic management bits bit 4 = h half carry . this bit is set by hardware when a carry occurs be- tween bits 3 and 4 of the alu during an add or adc instructions. it is reset by hardware during the same instructions. 0: no half carry has occurred. 1: a half carry has occurred. this bit is tested usin g the jrh or jrnh instruc- tion. the h bit is useful in bcd arithmetic subrou- tines. bit 2 = n negative . this bit is set and cleared by hardware. it is repre- sentative of the result sign of the last arithmetic, logical or data manipulation. it?s a copy of the re- sult 7 th bit. 0: the result of the last operation is positive or null. 1: the result of the last operation is negative (i.e. the most significant bit is a logic 1). this bit is accessed by the jrmi and jrpl instruc- tions. bit 1 = z zero . this bit is set and cleared by hardware. this bit in- dicates that the result of the last arithmetic, logical or data manipulation is zero. 0: the result of the last operation is different from zero. 1: the result of the last operation is zero. this bit is accessed by the jreq and jrne test instructions. bit 0 = c carry/borrow. this bit is set and cleared by hardware and soft- ware. it indicates an overflow or an underflow has occurred during the last arithmetic operation. 0: no overflow or underflow has occurred. 1: an overflow or underflow has occurred. this bit is driven by the scf and rcf instructions and tested by the jrc and jrnc instructions. it is also affected by the ?bit test and branch?, shift and rotate instructions. interrupt management bits bit 5,3 = i1, i0 interrupt the combination of the i1 and i0 bits gives the cur- rent interrupt software priority. these two bits are set/cleared by hardware when entering in interrupt. the loaded value is given by the corresponding bits in the interrupt software pri- ority registers (ixspr). they can be also set/ cleared by software with the rim, sim, iret, halt, wfi and push/pop instructions. see the interrupt management chapter for more details. 70 11i1hi0nz c interrupt software priority i1 i0 level 0 (main) 1 0 level 1 0 1 level 2 0 0 level 3 (= interrupt disable) 1 1 1
st7232a 20/154 central processing unit (cont?d) stack pointer (sp) read/write reset value: 01 ffh the stack pointer is a 16-bit register which is al- ways pointing to the next free location in the stack. it is then decremented after data has been pushed onto the stack and incremented before data is popped from the stack (see figure 8 ). since the stack is 256 bytes deep, the 8 most sig- nificant bits are forced by hardware. following an mcu reset, or after a re set stack pointer instruc- tion (rsp), the stack pointer contains its reset val- ue (the sp7 to sp0 bits are set) which is the stack higher address. the least significant byte of the stack pointer (called s) can be directly accessed by a ld in- struction. note: when the lower limit is exceeded, the stack pointer wraps around to the stack upper limit, with- out indicating the stack overflow. the previously stored information is then overwritten and there- fore lost. the stack also wraps in case of an under- flow. the stack is used to save the return address dur- ing a subroutine call and the cpu context during an interrupt. the user may also directly manipulate the stack by means of the push and pop instruc- tions. in the case of an interrupt, the pcl is stored at the first location pointed to by the sp. then the other registers are stored in the next locations as shown in figure 8 . ? when an interrupt is received, the sp is decre- mented and the context is pushed on the stack. ? on return from interrupt, the sp is incremented and the context is popped from the stack. a subroutine call occupies two locations and an in- terrupt five location s in the stack area. figure 8. stack manipulation example 15 8 00000001 70 sp7 sp6 sp5 sp4 sp3 sp2 sp1 sp0 pch pcl sp pch pcl sp pcl pch x a cc pch pcl sp pcl pch x a cc pch pcl sp pcl pch x a cc pch pcl sp sp y call subroutine interrupt event push y pop y iret ret or rsp @ 01ffh @ 0100h stack higher address = 01ffh stack lower address = 0100h 1
st7232a 21/154 6 supply, reset an d clock management the device includes a ran ge of utility features for securing the application in critical situations (for example in case of a power brown-out), and re- ducing the number of external components. an overview is shown in figure 10 . for more details, refer to dedicated parametric section. main features optional pll for multiplying the frequency by 2 reset sequence manager (rsm) multi-oscillator cloc k management (mo) ? 5 crystal/ceramic resonator oscillators 6.1 phase locked loop if the clock frequency input to the pll is in the range 2 to 4 mhz, the pll can be used to multiply the frequency by two to obtain an f osc2 of 4 to 8 mhz. the pll is enabled by option byte. if the pll is disabled, then f osc2 = f osc /2. caution: the pll is not recommended for appli- cations where timing accuracy is required. figure 9. pll block diagram figure 10. clock, reset and supply block diagram 0 1 pll option bit pll x 2 f osc2 / 2 f osc f osc2 multi- oscillator (mo) osc1 reset v ss v dd reset sequence manager (rsm) osc2 main clock controller pll system integrity management watchdog sicsr timer (wdg) with realtime clock (mcc/rtc) wdg rf f osc (option) 0 f cpu 0 0 0 1
st7232a 22/154 6.2 multi-osc illator (mo) the main clock of the st7 can be generated by two different source types coming from the multi- oscillator block: an external source 4 crystal or ceramic resonator oscillators each oscillator is optimi zed for a given frequency range in terms of consumption and is selectable through the option byte. the associated hardware configurations are shown in table 5 . refer to the electrical characteristics section for more details. caution: the osc1 and/or osc2 pins must not be left unconnected. for the purposes of failure mode and effect analysis, it should be noted that if the osc1 and/or osc2 pins are left unconnected, the st7 main oscillator may start and, in this con- figuration, could generate an f osc clock frequency in excess of the allowed maximum (>16mhz.), putting the st7 in an unsafe/undefined state. the product behaviour must therefore be considered undefined when the osc pins are left unconnect- ed. external clock source in this external clock mode, a clock signal (square, sinus or triangle) with ~50% duty cycle has to drive the osc1 pin while the osc2 pin is tied to ground. crystal/ceramic oscillators this family of oscillators has the advan tage of pro- ducing a very accurate rate on the main clock of the st7. the selection with in a list of 4 oscillators with different frequency ranges has to be done by option byte in order to reduce consumption (refer to section 14.1 on page 142 for more details on the frequency ranges). in this mode of the multi- oscillator, the re sonator and the load capacitors have to be placed as close as possible to the oscil- lator pins in order to minimize output distortion and start-up stabilization ti me. the loading capaci- tance values must be adjusted according to the selected oscillator. these oscillators are no t stopped during the reset phase to avoid losing time in the oscillator start-up phase. table 5. st7 clock sources hardware configuration external clock crystal/ceramic resonators osc1 osc2 external st7 source osc1 osc2 load capacitors st7 c l2 c l1 1
st7232a 23/154 6.3 reset sequence manager (rsm) 6.3.1 introduction the reset sequence manager includes two re- set sources as shown in figure 12 : external reset source pulse internal watchdog reset these sources act on the reset pin and it is al- ways kept low during the delay phase. the reset service routine vector is fixed at ad- dresses fffeh-ffffh in the st7 memory map. the basic reset sequence consists of 3 phases as shown in figure 11 : active phase depending on the reset source 256 or 4096 cpu clock cycle delay (selected by option byte) reset vector fetch the 256 or 4096 cpu clock cycle delay allows the oscillator to stabilise an d ensures that recovery has taken place from the reset state. the shorter or longer clock cycle delay should be selected by option byte to correspond to the stabilization time of the external oscillator used in the application. the reset vector fetch phase duration is 2 clock cycles. figure 11. reset sequence phases 6.3.2 asynchronous external reset pin the reset pin is both an input and an open-drain output with integrated r on weak pull-up resistor. this pull-up has no fixed value but varies in ac- cordance with the input voltage. it can be pulled low by external circuitry to reset the device. see electrical characteristic section for more details. a reset signal originating from an external source must have a duration of at least t h(rstl)in in order to be recognized (see figure 13 ). this de- tection is asynchronous and therefore the mcu can enter reset state even in halt mode. figure 12. reset block diagram reset active phase internal reset 256 or 4096 clock cycles fetch vector reset r on v dd watchdog reset internal reset pulse generator filter 1
st7232a 24/154 reset sequence manager (cont?d) the reset pin is an asynchronous signal which plays a major role in ems performance. in a noisy environment, it is recommended to follow the guidelines mentioned in the electrical characteris- tics section. 6.3.3 external power-on reset to start up the microcontroller correctly, the user must ensure by means of an external reset circuit that the reset signal is held low until v dd is over the minimum level specified for the selected f osc frequency. a proper reset signal for a slow rising v dd supply can generally be provided by an external rc net- work connected to the reset pin. 6.3.4 internal watchdog reset the reset sequence gene rated by a internal watchdog counter overflow is shown in figure 13 . starting from the watchdog counter underflow, the device reset pin acts as an output that is pulled low during at least t w(rstl)out . figure 13. reset sequences reset pin external watchdog t h(rstl)in run watchdog underflow t w(rstl)out run run reset reset source external reset watchdog reset internal reset (256 or 4096 t cpu ) vector fetch active phase active phase 1
st7232a 25/154 6.4 system integrity management 6.4.1 register description system integrity (si) control/status register (sicsr) read/write reset value: 0000 000x (00h) bits 7:1 = reserved, must be kept cleared. bit 0 = wdgrf watchdog reset flag this bit indicates that the last reset was generat- ed by the watchdog peripheral. it is set by hard- ware (watchdog reset) and cleared by software (writing zero) . 70 0000000 wdg rf 1
st7232a 26/154 7 interrupts 7.1 introduction the st7 enhanced interrupt management pro- vides the following features: hardware interrupts software interrupt (trap) nested or concurrent interrupt management with flexible interrup t priority and level management: ? up to 4 software programmable nesting levels ? up to 16 interrupt vectors fixed by hardware ? 2 non maskable events: reset, trap this interrupt management is based on: ? bit 5 and bit 3 of the cpu cc register (i1:0), ? interrupt software priority registers (isprx), ? fixed interrupt vector addresses located at the high addresses of the memory map (ffe0h to ffffh) sorted by hardware priority order. this enhanced interrupt controller guarantees full upward compatibility with th e standard (not nest- ed) st7 interrupt controller. 7.2 masking and processing flow the interrupt masking is managed by the i1 and i0 bits of the cc register and the isprx registers which give the interrupt so ftware priority level of each interrupt vector (see table 6 ). the process- ing flow is shown in figure 14 when an interrupt request has to be serviced: ? normal processing is suspended at the end of the current instruction execution. ? the pc, x, a and cc registers are saved onto the stack. ? i1 and i0 bits of cc register are set according to the corresponding values in the isprx registers of the serviced interrupt vector. ? the pc is then loaded with the interrupt vector of the interrupt to service and the first instruction of the interrupt service routine is fetched (refer to ?interrupt mapping? table for vector addresses). the interrupt service routine should end with the iret instruction which causes the contents of the saved registers to be recovered from the stack. note : as a consequence of the iret instruction, the i1 and i0 bits will be restored from the stack and the program in the pr evious level will resume. table 6. interrupt software priority levels figure 14. interrupt processing flowchart interrupt software priority level i1 i0 level 0 (main) low high 10 level 1 0 1 level 2 0 0 level 3 (= interrupt disable) 1 1 ?iret? restore pc, x, a, cc stack pc, x, a, cc load i1:0 from interrupt sw reg. fetch next reset trap pending instruction i1:0 from stack load pc from interrupt vector y n y n y n interrupt has the same or a lower software priority the interrupt stays pending than current one interrupt has a higher software priority than current one execute instruction interrupt 1
st7232a 27/154 interrupts (cont?d) servicing pending interrupts as several interrupts can be pending at the same time, the interrupt to be taken into account is deter- mined by the following two-step process: ? the highest software priority interrupt is serviced, ? if several interr upts have the same software pri- ority then the interrupt with the highest hardware priority is serviced first. figure 15 describes this decision process. figure 15. priority decision process when an interrupt request is not serviced immedi- ately, it is latched and then processed when its software priority combined with the hardware pri- ority becomes the highest one. note 1 : the hardware priority is exclusive while the software one is not. this allows the previous process to succeed with only one interrupt. note 2 : reset and trap can be considered as having the highest software priority in the decision process. different interrupt vector sources two interrupt source types are managed by the st7 interrupt controller: the non-maskable type (reset,trap) and the maskable type (external or from internal peripherals). non-maskable sources these sources are processed regardless of the state of the i1 and i0 bits of the cc register (see figure 14 ). after stacking the pc, x, a and cc registers (except for r eset), the co rresponding vector is loaded in the pc register and the i1 and i0 bits of the cc are set to disable interrupts (level 3). these sources allow the processor to exit halt mode. trap (non maskable software interrupt) this software interrupt is serviced when the trap instruction is executed. it will be serviced accord- ing to the flowchart in figure 14 . reset the reset source has the highest priority in the st7. this means that the first current routine has the highest software priority (level 3) and the high- est hardware priority. see the reset chapter for more details. maskable sources maskable interrupt vector sources can be serviced if the corresponding interrupt is enabled and if its own interrupt software priority (in isprx registers) is higher than the one currently being serviced (i1 and i0 in cc register). if any of these two condi- tions is false, the interrupt is latched and thus re- mains pending. external interrupts external interrupts allow the processor to exit from halt low power mode. external interrupt sensitiv- ity is software selectable through the external in- terrupt control register (eicr). external interrupt triggered on edge will be latched and the interrupt request automatically cleared upon entering the interrupt service routine. if several input pins of a group connected to the same interrupt line are selected simultaneously, these will be logically ored. peripheral interrupts usually the peripheral interrupts cause the mcu to exit from halt mode except those mentioned in the ?interrupt mapping? table. a peripheral inter- rupt occurs when a specific flag is set in the pe- ripheral status registers and if the corresponding enable bit is set in the peripheral control register. the general sequence for clearing an interrupt is based on an access to the status register followed by a read or write to an associated register. note : the clearing sequence resets the internal latch. a pending interrupt (i.e. waiting for being serviced) will theref ore be lost if the clear se- quence is executed. pending software different interrupts same highest hardware priority serviced priority highest software priority serviced 1
st7232a 28/154 interrupts (cont?d) 7.3 interrupts and low power modes all interrupts allow the processor to exit the wait low power mode. on the contrary, only external and other specified interrupts allow the processor to exit from the halt modes (see column ?exit from halt? in ?interrupt mapping? table). when several pending interrupts are present while exit- ing halt mode, the first one serviced can only be an interrupt with ex it from halt mode capability and it is selected through the same decision proc- ess shown in figure 15 . note : if an interrupt, that is not able to exit from halt mode, is pending with the highest priority when exiting halt mode, this interrupt is serviced after the first one serviced. 7.4 concurrent & nested management the following figure 16 and figure 17 show two different interrupt management modes. the first is called concurrent mode and does not allow an in- terrupt to be interrupted, unlike the nested mode in figure 17 . the interrupt hardware priority is given in this order from the lowest to the highest: main, it4, it3, it2, it1, it0. the software priority is giv- en for each interrupt. warning : a stack overflow may occur without no- tifying the software of the failure. figure 16. concurrent interrupt management figure 17. nested interrupt management main it4 it2 it1 trap it1 main it0 i1 hardware priority software 3 3 3 3 3 3/0 3 11 11 11 11 11 11 / 10 11 rim it2 it1 it4 trap it3 it0 it3 i0 10 priority level used stack = 10 bytes main it2 trap main it0 it2 it1 it4 trap it3 it0 hardware priority 3 2 1 3 3 3/0 3 11 00 01 11 11 11 rim it1 it4 it4 it1 it2 it3 i1 i0 11 / 10 10 software priority level used stack = 20 bytes 1
st7232a 29/154 interrupts (cont?d) 7.5 interrupt register description cpu cc register interrupt bits read/write reset value: 111x 1010 (xah) bit 5, 3 = i1, i0 software interrupt priority these two bits indicate the current interrupt soft- ware priority. these two bits are set/cleared by hardware when entering in interrupt. the loaded value is given by the corresponding bits in the interrupt software pri- ority registers (isprx). they can be also set/cleared by software with the rim, sim, halt, wfi, iret and push/pop in- structions (see ?interrupt dedicated instruction set? table). *note : trap and reset even ts can interrupt a level 3 program. interrupt software priority regis- ters (isprx) read/write (bit 7:4 of ispr3 are read only) reset value: 1111 1111 (ffh) these four registers contain the interrupt software priority of each interrupt vector. ? each interrupt vector (except reset and trap) has corresponding bits in these registers where its own software priority is stored. this corre- spondance is shown in the following table. ? each i1_x and i0_x bit value in the isprx regis- ters has the same meaning as the i1 and i0 bits in the cc register. ? level 0 can not be written (i1_x=1, i0_x=0). in this case, the previously stored value is kept. (ex- ample: previous=cfh, write=64h, result=44h) the reset, and trap vectors have no software priorities. when one is serviced, the i1 and i0 bits of the cc register are both set. caution : if the i1_x and i0_x bits are modified while the interrupt x is executed the following be- haviour has to be considered: if the interrupt x is still pending (new interrupt or flag not cleared) and the new software priority is higher than the previ- ous one, the interrupt x is re-entered. otherwise, the software priority stays unchanged up to the next interrupt request (after the iret of the inter- rupt x). 70 11 i1 h i0 nzc interrupt software priority level i1 i0 level 0 (main) low high 10 level 1 0 1 level 2 0 0 level 3 (= interrupt disable*) 1 1 70 ispr0 i1_3 i0_3 i1_2 i0_2 i1_1 i0_1 i1_0 i0_0 ispr1 i1_7 i0_7 i1_6 i0_6 i1_5 i0_5 i1_4 i0_4 ispr2 i1_11 i0_11 i1_10 i0_10 i1_9 i0_9 i1_8 i0_8 ispr3 1 1 1 1 i1_13 i0_13 i1_12 i0_12 vector address isprx bits fffbh-fffah i1_0 and i0_0 bits* fff9h-fff8h i1_1 and i0_1 bits ... ... ffe1h-ffe0h i1_13 and i0_13 bits 1
st7232a 30/154 interrupts (cont?d) table 7. dedicated interrupt instruction set note : during the execution of an interrupt routine, the halt, popcc, rim, si m and wfi instructions change the current software priority up to the next iret instructi on or one of the previously mentioned instructions. instruction new descripti on function/example i1 h i0 n z c halt entering halt mode 1 0 iret interrupt routine return pop cc, a, x, pc i1 h i0 n z c jrm jump if i1:0=11 (level 3) i1:0=11 ? jrnm jump if i1:0<>11 i1:0<>11 ? pop cc pop cc from the stack mem => cc i1 h i0 n z c rim enable interrupt (level 0 set) load 10 in i1:0 of cc 1 0 sim disable interrupt (level 3 set) load 11 in i1:0 of cc 1 1 trap software trap software nmi 1 1 wfi wait for interrupt 1 0 1
st7232a 31/154 interrupts (cont?d) table 8. interrupt mapping note 1: unexpected exit from halt may occur when spi is in slave mode. 7.6 external interrupts 7.6.1 i/o port interrupt sensitivity the external interrupt se nsitivity is controlled by the ipa, ipb and isxx bits of the eicr register ( figure 18 ). this control allows to have up to 4 fully independent external interrupt source sensitivities. each external interrupt source can be generated on four (or five) different events on the pin: falling edge rising edge falling and rising edge falling edge and low level rising edge and high level (only for ei0 and ei2) to guarantee correct functionality, the sensitivity bits in the eicr register can be modified only when the i1 and i0 bits of the cc register are both set to 1 (level 3). this means that interrupts must be disabled before changing sensitivity. the pending interrupts are cleared by writing a dif- ferent value in the isx[1:0], ipa or ipb bits of the eicr. n source block description register label priority order exit from halt exit from active halt address vector reset reset n/a yes yes fffeh-ffffh trap software interrupt no no fffch-fffdh 0 not used fffah-fffbh 1 mcc/rtc main clock controller time base inter- rupt mccsr higher priority yes yes fff8h-fff9h 2 ei0 external interrupt port a3..0 n/a yes no fff6h-fff7h 3 ei1 external interrupt port f2..0 yes no fff4h-fff5h 4 ei2 external interrupt port b3..0 yes no fff2h-fff3h 5 ei3 external interrupt port b7..4 yes no fff0h-fff1h 6 not used ffeeh-ffefh 7 spi spi peripheral interrupts spicsr yes 1) no ffech-ffedh 8 timer a timer a peripheral interrupts tasr no no ffeah-ffebh 9 timer b timer b peripheral interrupts tbsr no no ffe8h-ffe9h 10 sci sci peripheral interrupts scisr lower priority no no ffe6h-ffe7h 11 not used ffe4h-ffe5h 1
st7232a 32/154 figure 18. external interrupt control bits is10 is11 eicr sensitivity control pbor.3 pbddr.3 ipb bit pb3 ei2 interrupt source port b [3:0] interrupts pb3 pb2 pb1 pb0 is10 is11 eicr sensitivity control pbor.7 pbddr.7 pb7 ei3 interrupt source port b [7:4] interrupts pb7 pb6 pb5 pb4 is20 is21 eicr sensitivity control paor.3 paddr.3 ipa bit pa3 ei0 interrupt source port a3 interrupt is20 is21 eicr sensitivity control pfor.2 pfddr.2 pf2 ei1 interrupt source port f [2:0] interrupts pf2 pf1 pf0 1
st7232a 33/154 interrupts (cont?d) 7.7 external interrupt control register (eicr) read/write reset value: 0000 0000 (00h) bit 7:6 = is1[1:0] ei2 and ei3 sensitivity the interrupt sensitivity, defined using the is1[1:0] bits, is applied to the following external interrupts: - ei2 (port b3..0) - ei3 (port b4) these 2 bits can be written only when i1 and i0 of the cc register are both set to 1 (level 3). bit 5 = ipb interrupt polarity for port b this bit is used to invert the sensitivity of the port b [3:0] external interrupts. it can be set and cleared by software only when i1 and i0 of the cc register are both set to 1 (level 3). 0: no sensitivity inversion 1: sensitivity inversion bit 4:3 = is2[1:0] ei0 and ei1 sensitivity the interrupt sensitivity, defined using the is2[1:0] bits, is applied to the following external interrupts: - ei0 (port a3..0) - ei1 (port f2..0) these 2 bits can be written only when i1 and i0 of the cc register are both set to 1 (level 3). bit 2 = ipa interrupt polarity for port a this bit is used to invert the sensitivity of the port a [3:0] external interrupts. it can be set and cleared by software only when i1 and i0 of the cc register are both set to 1 (level 3). 0: no sensitivity inversion 1: sensitivity inversion bits 1:0 = reserved, must always be kept cleared. 70 is11 is10 ipb is21 is20 ipa 0 0 is11 is10 external interrupt sensitivity ipb bit =0 ipb bit =1 00 falling edge & low level rising edge & high level 0 1 rising edge only falling edge only 1 0 falling edge only rising edge only 1 1 rising and falling edge is11 is10 external interrupt sensitivity 0 0 falling edge & low level 0 1 rising edge only 1 0 falling edge only 1 1 rising and falling edge is21 is20 external interrupt sensitivity ipa bit =0 ipa bit =1 00 falling edge & low level rising edge & high level 0 1 rising edge only falling edge only 1 0 falling edge only rising edge only 1 1 rising and falling edge is21 is20 external interrupt sensitivity 0 0 falling edge & low level 0 1 rising edge only 1 0 falling edge only 1 1 rising and falling edge 1
st7232a 34/154 interrupts (cont?d) table 9. nested interrupts register map and reset values address (hex.) register label 76543210 0024h ispr0 reset value ei1 ei0 mcc + si i1_3 1 i0_3 1 i1_2 1 i0_2 1 i1_1 1 i0_1 111 0025h ispr1 reset value spi ei3 ei2 i1_7 1 i0_7 1 i1_6 1 i0_6 1 i1_5 1 i0_5 1 i1_4 1 i0_4 1 0026h ispr2 reset value avd sci timer b timer a i1_11 1 i0_11 1 i1_10 1 i0_10 1 i1_9 1 i0_9 1 i1_8 1 i0_8 1 0027h ispr3 reset value1111 i1_13 1 i0_13 1 i1_12 1 i0_12 1 0028h eicr reset value is11 0 is10 0 ipb 0 is21 0 is20 0 ipa 000 1
st7232a 35/154 8 power saving modes 8.1 introduction to give a large measure of flexibility to the applica- tion in terms of power consumption, four main power saving modes are implemented in the st7 (see figure 19 ): slow, wait (slow wait), ac- tive halt and halt. after a reset the normal operating mode is se- lected by default (run mode). this mode drives the device (cpu and embedded peripherals) by means of a master clock which is based on the main oscillator frequency di vided or multiplied by 2 (f osc2 ). from run mode, the different power saving modes may be selected by setting the relevant register bits or by callin g the specific st7 software instruction whose action depends on the oscillator status. figure 19. power saving mode transitions 8.2 slow mode this mode has two targets: ? to reduce power consumption by decreasing the internal clock in the device, ? to adapt the internal clock frequency (f cpu ) to the available supply voltage. slow mode is controlled by three bits in the mccsr register: the sms bit which enables or disables slow mode and two cpx bits which select the internal slow frequency (f cpu ). in this mode, the master clock frequency (f osc2 ) can be divided by 2, 4, 8 or 16. the cpu and pe- ripherals are clocked at this lower frequency (f cpu ). note : slow-wait mode is activated when enter- ing the wait mode while the device is already in slow mode. figure 20. slow mode clock transitions power consumption wait slow run active halt high low slow wait halt 00 01 sms cp1:0 f cpu new slow normal run mode mccsr frequency request request f osc2 f osc2 /2 f osc2 /4 f osc2 1
st7232a 36/154 power saving modes (cont?d) 8.3 wait mode wait mode places the mcu in a low power con- sumption mode by stopping the cpu. this power saving mode is selected by calling the ?wfi? instruction. all peripherals remain active. during wait mode, the i[1:0] bits of the cc register are forced to ?10?, to enable all interrupts. all other registers and memory remain unchanged. the mcu remains in wait mode until an interrupt or reset occurs, whereupon the program counter branches to the starting address of the interrupt or reset service routine. the mcu will remain in wa it mode until a reset or an interrupt occurs, causing it to wake up. refer to figure 21 . figure 21. wait mode flow-chart note: 1. before servicing an inte rrupt, the cc register is pushed on the stack. the i[1:0] bits of the cc reg- ister are set to the current software priority level of the interrupt routine and recovered when the cc register is popped. wfi instruction reset interrupt y n n y cpu oscillator peripherals i[1:0] bits on on 10 off fetch reset vector or service interrupt cpu oscillator peripherals i[1:0] bits on off 10 on cpu oscillator peripherals i[1:0] bits on on xx 1) on 256 or 4096 cpu clock cycle delay 1
st7232a 37/154 power saving modes (cont?d) 8.4 active-halt and halt modes active-halt and halt modes are the two low- est power consumption modes of the mcu. they are both entered by executing the ?halt? instruc- tion. the decision to enter either in active-halt or halt mode is given by the mcc/rtc interrupt enable flag (oie bit in mccsr register). 8.4.1 active-halt mode active-halt mode is the lowest power con- sumption mode of the mcu with a real time clock available. it is entered by executing the ?halt? in- struction when the oie bit of the main clock con- troller status register (mccsr) is set (see section 10.2 on page 51 for more details on the mccsr register). the mcu can exit active-halt mode on recep- tion of either an mcc/rtc interrupt, a specific in- terrupt (see table 8, ?interrupt mapping,? on page 31 ) or a reset. when exiting active- halt mode by means of an interrupt, no 256 or 4096 cpu cycle delay occurs. the cpu resumes operation by servicing the interrupt or by fetching the reset vector which woke it up (see figure 23 ). when entering active-halt mode, the i[1:0] bits in the cc register are forced to ?10b? to enable in- terrupts. therefore, if an interrupt is pending, the mcu wakes up immediately. in active-halt mode, on ly the main oscillator and its associated counter (mcc/rtc) are run- ning to keep a wake-up time base. all other periph- erals are not clocked except those which get their clock supply from another clock generator (such as external or auxiliary oscillator). the safeguard against staying locked in active- halt mode is provided by the oscillator interrupt. note: as soon as the interrupt capability of one of the oscillators is selected (mccsr.oie bit set), entering active-halt mode while the watchdog is active does not generate a reset. this means that the device cannot spend more than a defined delay in this power saving mode. caution: when exiting active-halt mode fol- lowing an interrupt, oie bit of mccsr register must not be cleared before t delay after the inter- rupt occurs (t delay = 256 or 4096 t cpu delay de- pending on option byte). otherwise, the st7 en- ters halt mode for the remaining t delay period. figure 22. active-halt timing overview figure 23. active-halt mode flow-chart notes: 1. this delay occurs only if the mcu exits active- halt mode by means of a reset. 2. peripheral clocked with an external clock source can still be active. 3. only the mcc/rtc inte rrupt and some specific interrupts can exit the mcu from active-halt mode (such as external interrupt). refer to table 8, ?interrupt mapping,? on page 31 for more details. 4. before servicing an inte rrupt, the cc register is pushed on the stack. the i[1:0] bits of the cc reg- ister are set to the current software priority level of the interrupt routine and restored when the cc register is popped. mccsr oie bit power saving mode entered when halt instruction is executed 0 halt mode 1 active-halt mode halt run run 256 or 4096 cpu cycle delay 1) reset or interrupt halt instruction fetch vector active [mccsr.oie=1] halt instruction reset interrupt 3) y n n y cpu oscillator peripherals 2) i[1:0] bits on off 10 off fetch reset vector or service interrupt cpu oscillator peripherals i[1:0] bits on off xx 4) on cpu oscillator peripherals i[1:0] bits on on xx 4) on 256or4096cpuclock cycle delay (mccsr.oie=1) 1
st7232a 38/154 power saving modes (cont?d) 8.4.2 halt mode the halt mode is the lo west power consumption mode of the mcu. it is entered by executing the ?halt? instruction when the oie bit of the main clock controller status register (mccsr) is cleared (see section 10.2 on page 51 for more de- tails on the mccsr register). the mcu can exit halt mode on reception of ei- ther a specific interrupt (see table 8, ?interrupt mapping,? on page 31 ) or a reset. when exiting halt mode by means of a reset or an interrupt, the oscillator is immedi ately turned on and the 256 or 4096 cpu cycle delay is used to stabilize the oscillator. afte r the start up delay, the cpu resumes operation by servicing the interrupt or by fetching the reset vector which woke it up (see fig- ure 25 ). when entering halt mode, the i[1:0] bits in the cc register are forced to ?10b?to enable interrupts. therefore, if an interrupt is pending, the mcu wakes up immediately. in halt mode, the main oscillator is turned off causing all internal processing to be stopped, in- cluding the operation of the on-chip peripherals. all peripherals are not clocked except the ones which get their clock supply from another clock generator (such as an external or auxiliary oscilla- tor). the compatibility of wa tchdog operation with halt mode is configured by the ?wdghalt? op- tion bit of the option byte. the halt instruction when executed while the watchdog system is en- abled, can generate a watchdog reset (see section 14.1 on page 142 ) for more details. figure 24. halt timing overview figure 25. halt mode flow-chart notes: 1. wdghalt is an option bit. see option byte sec- tion for more details. 2. peripheral clocked with an external clock source can still be active. 3. only some specific interrupts can exit the mcu from halt mode (such as external interrupt). re- fer to table 8, ?interrupt mapping,? on page 31 for more details. 4. before servicing an inte rrupt, the cc register is pushed on the stack. the i[1:0] bits of the cc reg- ister are set to the current software priority level of the interrupt routine and recovered when the cc register is popped. halt run run 256 or 4096 cpu cycle delay reset or interrupt halt instruction fetch vector [mccsr.oie=0] halt instruction reset interrupt 3) y n n y cpu oscillator peripherals 2) i[1:0] bits off off 10 off fetch reset vector or service interrupt cpu oscillator peripherals i[1:0] bits on off xx 4) on cpu oscillator peripherals i[1:0] bits on on xx 4) on 256 or 4096 cpu clock delay watchdog enable disable wdghalt 1) 0 watchdog reset 1 (mccsr.oie=0) cycle 1
st7232a 39/154 power saving modes (cont?d) 8.4.2.1 halt mode recommendations ? make sure that an external event is available to wake up the microcontroller from halt mode. ? when using an external interrupt to wake up the microcontroller, reinitia lize the corresponding i/o as ?input pull-up with interrupt? before executing the halt instruction. the main reason for this is that the i/o may be wrongly configured due to ex- ternal interference or by an unforeseen logical condition. ? for the same reason, reinitialize the level sensi- tiveness of each external interrupt as a precau- tionary measure. ? the opcode for the halt instruction is 0x8e. to avoid an unexpected halt instruction due to a program counter failure, it is advised to clear all occurrences of the data value 0x8e from memo- ry. for example, avoid defining a constant in rom with the value 0x8e. ? as the halt instruction clears the interrupt mask in the cc register to allow interrupts, the user may choose to clear all pending interrupt bits be- fore executing the halt instruction. this avoids entering other peripheral interrupt routines after executing the external interrupt routine corre- sponding to the wake-up event (reset or external interrupt). 1
st7232a 40/154 9 i/o ports 9.1 introduction the i/o ports offer different functional modes: ? transfer of data through digital inputs and outputs and for specific pins: ? external interrupt generation ? alternate signal input/output for the on-chip pe- ripherals. an i/o port contains up to 8 pins. each pin can be programmed independently as digital input (with or without interrupt generation) or digital output. 9.2 functional description each port has 2 main registers: ? data register (dr) ? data direction register (ddr) and one optional register: ? option register (or) each i/o pin may be programmed using the corre- sponding register bits in the ddr and or regis- ters: bit x corresponding to pin x of the port. the same correspondence is used for the dr register. the following description takes into account the or register, (for specific ports which do not pro- vide this register refer to the i/o port implementa- tion section). the generic i/o block diagram is shown in figure 26 9.2.1 input modes the input configuration is selected by clearing the corresponding ddr register bit. in this case, reading the dr register returns the digital value applied to the external i/o pin. different input modes can be selected by software through the or register. notes : 1. writing the dr register modifies the latch value but does not affect the pin status. 2. when switching from input to output mode, the dr register has to be written first to drive the cor- rect level on the pin as soon as the port is config- ured as an output. 3. do not use read/modify /write instructions (bset or bres) to modify the dr register external interrupt function when an i/o is configured as input with interrupt, an event on this i/o can generate an external inter- rupt request to the cpu. each pin can independently generate an interrupt request. the interrupt sens itivity is independently programmable using the sensitivity bits in the eicr register. each external interrupt vector is linked to a dedi- cated group of i/o port pins (see pinout description and interrupt section). if several input pins are se- lected simultaneously as interrupt sources, these are first detected according to the sensitivity bits in the eicr register and then logically ored. the external interrupts are hardware interrupts, which means that the request latch (not accessible directly by the applicati on) is automatically cleared when the corresponding interrupt vector is fetched. to clear an unwanted pending interrupt by software, the sensitivity bits in the eicr register must be modified. 9.2.2 output modes the output configuration is selected by setting the corresponding ddr register bit. in this case, writ- ing the dr register applies this digital value to the i/o pin through the latch. then reading the dr reg- ister returns the previously stored value. two different output modes can be selected by software through the or register: output push-pull and open-drain. dr register value and output pin status: 9.2.3 alternate functions when an on-chip peripheral is configured to use a pin, the alternate function is automatically select- ed. this alternate function takes priority over the standard i/o programming. when the signal is coming from an on-chip periph- eral, the i/o pin is automatically configured in out- put mode (push-pull or open drain according to the peripheral). when the signal is going to an on-chip peripheral, the i/o pin must be configured in input mode. in this case, the pin state is also digitally readable by addressing the dr register. note : input pull-up configuration can cause unex- pected value at the input of the alternate peripheral input. when an on-chip peripheral use a pin as in- put and output, this pin has to be configured in in- put floating mode. dr push-pull open-drain 0v ss vss 1v dd floating 1
st7232a 41/154 i/o ports (cont?d) figure 26. i/o port general block diagram table 10. i/o port mode options legend : ni - not implemented off - implemented not activated on - implemented and activated note : the diode to v dd is not implemented in the true open drain pads. a local protection between the pad and v ss is implemented to protect the de- vice against positive stress. configuration mode pull-up p-buffer diodes to v dd to v ss input floating with/without interrupt off off on on pull-up with/without interrupt on output push-pull off on open drain (logic level) off true open drain ni ni ni (see note) dr ddr or data bus pad v dd alternate enable alternate output 1 0 or sel ddr sel dr sel pull-up condition p-buffer (see table below) n-buffer pull-up (see table below) 1 0 analog input if implemented alternate input v dd diodes (see table below) external source (ei x ) interrupt cmos schmitt trigger register access 1
st7232a 42/154 i/o ports (cont?d) table 11. i/o port configurations notes: 1. when the i/o port is in input configuration and the associated alternate function is enabled as an output, reading the dr register will read the alternate function output status. 2. when the i/o port is in output configuration and th e associated alternate function is enabled as an input, the alternate function reads the pin status given by the dr register content. hardware configuration input 1) open-drain output 2) push-pull output 2) condition pad v dd r pu external interrupt data b u s pull-up interrupt dr register access w r source (ei x ) dr register condition alternate input not implemented in true open drain i/o ports analog input pad r pu data b u s dr dr register access r/w v dd alternate alternate enable output register not implemented in true open drain i/o ports pad r pu data b u s dr dr register access r/w v dd alternate alternate enable output register not implemented in true open drain i/o ports 1
st7232a 43/154 i/o ports (cont?d) caution : the alternate function must not be ac- tivated as long as the pin is configured as input with interrupt, in order to avoid generating spurious interrupts. analog alternate function when the pin is used as an adc input, the i/o must be configured as floating input. the analog multiplexer (controlled by the adc registers) switches the analog voltage present on the select- ed pin to the common analog rail which is connect- ed to the adc input. it is recommended not to change the voltage level or loading on any port pin while conversion is in progress. furthermore it is recommended not to have clocking pins located close to a selected an- alog pin. warning : the analog input voltage level must be within the limits stated in the absolute maxi- mum ratings. 9.3 i/o port implementation the hardware implementation on each i/o port de- pends on the settings in the ddr and or registers and specific feature of the i/o port such as adc in- put or true open drain. switching these i/o ports from one state to anoth- er should be done in a sequence that prevents un- wanted side effects. recommended safe transi- tions are illustrated in figure 27 other transitions are potentially risky and should be avoided, since they are likely to present unwanted side-effects such as spurious interrupt generation. figure 27. interrupt i/o port state transitions 9.4 low power modes 9.5 interrupts the external interrupt event generates an interrupt if the corresponding configuration is selected with ddr and or registers and the interrupt mask in the cc register is not active (rim instruction). mode description wait no effect on i/o ports. external interrupts cause the device to exit from wait mode. halt no effect on i/o ports. external interrupts cause the device to exit from halt mode. interrupt event event flag enable control bit exit from wait exit from halt external interrupt on selected external event - ddrx orx yes yes 01 floating/pull-up interrupt input 00 floating (reset state) input 10 open-drain output 11 push-pull output xx = ddr, or 1
st7232a 44/154 i/o ports (cont?d) 9.5.1 i/o port implementation the i/o port register configurations are summa- rised as follows. standard ports pa5:4, pc7:0, pd5:0, pe1:0, pf7:6, 4 interrupt ports pb4, pb2:0, pf1:0 (with pull-up) pa3, pb3, pf2 (without pull-up) true open drain ports pa7:6 table 12. port configuration mode ddr or floating input 0 0 pull-up input 0 1 open drain output 1 0 push-pull output 1 1 mode ddr or floating input 0 0 pull-up interrupt input 0 1 open drain output 1 0 push-pull output 1 1 mode ddr or floating input 0 0 floating interrupt input 0 1 open drain output 1 0 push-pull output 1 1 mode ddr floating input 0 open drain (high sink ports) 1 port pin name input output or = 0 or = 1 or = 0 or = 1 port a pa7:6 floating true open-drain pa5:4 floating pull-up open drain push-pull pa3 floating floating interrupt open drain push-pull port b pb3 floating floating interrupt open drain push-pull pb4, pb2:0 floating pull-up interrupt open drain push-pull port c pc7:0 floating pull-up open drain push-pull port d pd5:0 floating pull-up open drain push-pull port e pe1:0 floating pull-up open drain push-pull port f pf7:6, 4 floating pull-up open drain push-pull pf2 floating floating interrupt open drain push-pull pf1:0 floating pull-up interrupt open drain push-pull 1
st7232a 45/154 i/o ports (cont?d) table 13. i/o port register map and reset values address (hex.) register label 76543210 reset value of all i/o port registers 00000000 0000h padr msb lsb 0001h paddr 0002h paor 0003h pbdr msb lsb 0004h pbddr 0005h pbor 0006h pcdr msb lsb 0007h pcddr 0008h pcor 0009h pddr msb lsb 000ah pdddr 000bh pdor 000ch pedr msb lsb 000dh peddr 000eh peor 000fh pfdr msb lsb 0010h pfddr 0011h pfor 1
st7232a 46/154 10 on-chip peripherals 10.1 watchdog timer (wdg) 10.1.1 introduction the watchdog timer is used to detect the occur- rence of a software fault, usually generated by ex- ternal interference or by unforeseen logical condi- tions, which causes the application program to abandon its normal sequence. the watchdog cir- cuit generates an mcu reset on expiry of a pro- grammed time period, unless the program refresh- es the counter?s contents before the t6 bit be- comes cleared. 10.1.2 main features programmable free-running downcounter programmable reset reset (if watchdog activated) when the t6 bit reaches zero optional reset on halt instruction (configurable by option byte) hardware watchdog selectable by option byte 10.1.3 functional description the counter value stored in the watchdog control register (wdgcr bits t[6:0]), is decremented every 16384 f osc2 cycles (approx.), and the length of the timeout period can be programmed by the user in 64 increments. if the watchdog is activated (the wdga bit is set) and when the 7-bit timer (bits t[6:0]) rolls over from 40h to 3fh (t6 becomes cleared), it initiates a reset cycle pulling low th e reset pin for typically 500ns. the application program must write in the wdgcr register at regular intervals during normal operation to prevent an mcu reset. this down- counter is free-running: it counts down even if the watchdog is disabled. the value to be stored in the wdgcr register must be between ffh and c0h: ? the wdga bit is set (watchdog enabled) ? the t6 bit is set to prevent generating an imme- diate reset ? the t[5:0] bits contain the number of increments which represents the time delay before the watchdog produces a reset (see figure 29. ap- proximate timeout duration ). the timing varies between a minimum and a maximum value due to the unknown status of the prescaler when writ- ing to the wdgcr register (see figure 30 ). following a reset, the watchdog is disabled. once activated it cannot be disabled, except by a reset. the t6 bit can be used to generate a software re- set (the wdga bit is set and the t6 bit is cleared). if the watchdog is activated, the halt instruction will generate a reset. figure 28. watchdog block diagram reset wdga 6-bit downcounter (cnt) f osc2 t6 t0 wdg prescaler watchdog control register (wdgcr) div 4 t1 t2 t3 t4 t5 12-bit mcc rtc counter msb lsb div 64 0 5 6 11 mcc/rtc tb[1:0] bits (mccsr register) 1
st7232a 47/154 watchdog timer (cont?d) 10.1.4 how to program the watchdog timeout figure 29 shows the linear relationship between the 6-bit value to be loaded in the watchdog coun- ter (cnt) and the resulting timeout duration in mil- liseconds. this can be used for a quick calculation without taking the timing variations into account. if more precision is needed, use the formulae in fig- ure 30 . caution: when writing to the wdgcr register, al- ways write 1 in the t6 bit to avoid generating an immediate reset. figure 29. approximate timeout duration cnt value (hex.) watchdog timeout (ms) @ 8 mhz. f osc2 3f 00 38 128 1.5 65 30 28 20 18 10 08 50 34 18 82 98 114 1
st7232a 48/154 watchdog timer (cont?d) figure 30. exact timeout duration (t min and t max ) where : t min0 = (lsb + 128) x 64 x t osc2 t max0 = 16384 x t osc2 t osc2 = 125ns if f osc2 =8 mhz cnt = value of t[5:0] bits in the wdgcr register (6 bits) msb and lsb are values from the table below depending on the timebase selected by the tb[1:0] bits in the mccsr register to calculate the minimum watchdog timeout (t min ): if then else to calculate the maximum watchdog timeout (t max ): if then else note: in the above formulae, division results must be rounded down to the next integer value. example: with 2ms timeout selected in mccsr register tb1 bit (mccsr reg.) tb0 bit (mccsr reg.) selected mccsr timebase msb lsb 0 0 2ms 4 59 0 1 4ms 8 53 1 0 10ms 20 35 1 1 25ms 49 54 value of t[5:0] bits in wdgcr register (hex.) min. watchdog timeout (ms) t min max. watchdog timeout (ms) t max 00 1.496 2.048 3f 128 128.552 cnt msb 4 ------------- < t min t min0 16384 cnt t osc2 + = t min t min0 16384 cnt 4cnt msb ---------------- - ? ?? ?? 192 lsb + () 64 4cnt msb ---------------- - + t osc2 + = cnt msb 4 ------------- t max t max0 16384 cnt t osc2 + = t max t max0 16384 cnt 4cnt msb ---------------- - ? ?? ?? 192 lsb + () 64 4cnt msb ---------------- - + t osc2 + = 1
st7232a 49/154 watchdog timer (cont?d) 10.1.5 low power modes 10.1.6 hardware watchdog option if hardware watchdog is selected by option byte, the watchdog is always active and the wdga bit in the wdgcr is not used. refer to the option byte description. 10.1.7 using halt mode with the wdg (wdghalt option) the following recomme ndation applies if halt mode is used when the watchdog is enabled. ? before executing the halt instruction, refresh the wdg counter, to avoid an unexpected wdg reset immediately after waking up the microcon- troller. 10.1.8 interrupts none. 10.1.9 register description control register (wdgcr) read/write reset value: 0111 1111 (7fh) bit 7 = wdga activation bit . this bit is set by software and only cleared by hardware after a reset. when wdga = 1, the watchdog can generate a reset. 0: watchdog disabled 1: watchdog enabled note: this bit is not used if the hardware watch- dog option is enabled by option byte. bit 6:0 = t[6:0] 7-bit counter (msb to lsb). these bits contain the value of the watchdog counter. it is decremented every 16384 f osc2 cy- cles (approx.). a reset is produced when it rolls over from 40h to 3fh (t6 becomes cleared). mode description slow no effect on watchdog. wait no effect on watchdog. halt oie bit in mccsr register wdghalt bit in option byte 00 no watchdog reset is generated. the mcu enters halt mode. the watch- dog counter is decremented once and t hen stops counting and is no longer able to generate a watchdog reset until the mcu receives an external inter- rupt or a reset. if an external interrupt is received, the watchdog restarts counting after 256 or 4096 cpu clocks. if a reset is gener ated, the watchdog is disabled (reset state) unless hardware watchdog is selected by option byte. for applica- tion recommendations see section 10.1.7 below. 0 1 a reset is generated. 1x no reset is generated. the mcu ente rs active halt mode. the watchdog counter is not decremented. it stop counting. when the mcu receives an oscillator interrupt or external inte rrupt, the watchdog restarts counting im- mediately. when the mcu receives a reset the watchdog restarts counting after 256 or 4096 cpu clocks. 70 wdga t6 t5 t4 t3 t2 t1 t0 1
st7232a 50/154 table 14. watchdog timer register map and reset values address (hex.) register label 76543210 002ah wdgcr reset value wdga 0 t6 1 t5 1 t4 1 t3 1 t2 1 t1 1 t0 1 1
st7232a 51/154 10.2 main clock controller with real time clock and beeper (mcc/rtc) the main clock controller co nsists of three differ- ent functions: a programmable cpu clock prescaler a clock-out signal to supply external devices a real time clock timer with interrupt capability each function can be used independently and si- multaneously. 10.2.1 programmable cpu clock prescaler the programmable cpu clock prescaler supplies the clock for the st7 cpu and its internal periph- erals. it manages slow power saving mode (see section 8.2 slow mode for more details). the prescaler selects the f cpu main clock frequen- cy and is controlled by three bits in the mccsr register: cp[1:0] and sms. 10.2.2 clock-out capability the clock-out capability is an alternate function of an i/o port pin that outputs a f osc2 clock to drive external devices. it is controlled by the mco bit in the mccsr register. caution : when selected, the clock out pin sus- pends the clock during active-halt mode. 10.2.3 real time clock timer (rtc) the counter of the real time clock timer allows an interrupt to be generated based on an accurate real time clock. four different time bases depend- ing directly on f osc2 are available. the whole functionality is controlled by four bits of the mcc- sr register: tb[1:0], oie and oif. when the rtc interrupt is enabled (oie bit set), the st7 enters active-halt mode when the halt instruction is executed. see section 8.4 ac- tive-halt and halt modes for more details. 10.2.4 beeper the beep function is controlled by the mccbcr register. it can output three selectable frequencies on the beep pin (i/o port alternate function). figure 31. main clock controller (mcc/rtc) block diagram div 2, 4, 8, 16 mcc/rtc interrupt sms cp1 cp0 tb1 tb0 oie oif cpu clock mccsr 12-bit mcc rtc counter to cpu and peripherals f osc2 f cpu mco mco bc1 bc0 mccbcr beep selection beep signal 1 0 to watchdog timer div 64 1
st7232a 52/154 main clock controller with real time clock (cont?d) 10.2.5 low power modes 10.2.6 interrupts the mcc/rtc interrupt event generates an inter- rupt if the oie bit of the mccsr register is set and the interrupt mask in the cc register is not active (rim instruction). note : the mcc/rtc interrupt wakes up the mcu from active-halt mode, not from halt mode. 10.2.7 register description mcc control/status register (mccsr) read/write reset value: 0000 0000 (00h ) bit 7 = mco main clock out selection this bit enables the mco al ternate function on the pf0 i/o port. it is set and cleared by software. 0: mco alternate function disabled (i/o pin free for general-purpose i/o) 1: mco alternate function enabled (f cpu on i/o port) note : to reduce power consumption, the mco function is not active in active-halt mode. bit 6:5 = cp[1:0] cpu clock prescaler these bits select the cpu clock prescaler which is applied in the different slow modes. their action is conditioned by the setting of the sms bit. these two bits are set and cleared by software bit 4 = sms slow mode select this bit is set and cleared by software. 0: normal mode. f cpu = f osc2 1: slow mode. f cpu is given by cp1, cp0 see section 8.2 slow mode and section 10.2 main clock controller with real time clock and beeper (mcc/rtc) for more de- tails. bit 3:2 = tb[1:0] time base control these bits select the programmable divider time base. they are set and cleared by software. a modification of the time base is taken into ac- count at the end of the current period (previously set) to avoid an unwanted time shift. this allows to use this time base as a real time clock. bit 1 = oie oscillator interrupt enable this bit set and cleared by software. 0: oscillator interrupt disabled 1: oscillator interrupt enabled this interrupt can be used to exit from active- halt mode. when this bit is set, calling the st7 software halt instruction enters the active-halt power saving mode . mode description wait no effect on mcc/rtc peripheral. mcc/rtc interrupt cause the device to exit from wait mode. active- halt no effect on mcc/rtc counter (oie bit is set), the registers are frozen. mcc/rtc interrupt cause the device to exit from active-halt mode. halt mcc/rtc counter and registers are frozen. mcc/rtc operation resumes when the mcu is woken up by an interrupt with ?exit from halt? capability. interrupt event event flag enable control bit exit from wait exit from halt time base overflow event oif oie yes no 1) 70 mco cp1 cp0 sms tb1 tb0 oie oif f cpu in slow mode cp1 cp0 f osc2 / 2 0 0 f osc2 / 4 0 1 f osc2 / 8 1 0 f osc2 / 16 1 1 counter prescaler time base tb1 tb0 f osc2 =4mhz f osc2 =8mhz 16000 4ms 2ms 0 0 32000 8ms 4ms 0 1 80000 20ms 10ms 1 0 200000 50ms 25ms 1 1 1
st7232a 53/154 main clock controller with real time clock (cont?d) bit 0 = oif oscillator interrupt flag this bit is set by hardware and cleared by software reading the mccsr register. it indicates when set that the main oscillator has reached the selected elapsed time (tb1:0). 0: timeout not reached 1: timeout reached caution : the bres and b set instructions must not be used on the mccsr register to avoid unintentionally clearing the oif bit. mcc beep control register (mccbcr) read/write reset value: 0000 0000 (00h) bit 7:2 = reserved, must be kept cleared. bit 1:0 = bc[1:0] beep control these 2 bits select the pf1 pin beep capability. the beep output signal is available in active- halt mode but has to be disabled to reduce the consumption. table 15. main clock controller register map and reset values 70 000000bc1bc0 bc1 bc0 beep mode with f osc2 =8mhz 00 off 01 ~2-khz output beep signal ~50% duty cycle 10 ~1-khz 1 1 ~500-hz address (hex.) register label 76543210 002ch mccsr reset value mco 0 cp1 0 cp0 0 sms 0 tb1 0 tb0 0 oie 0 oif 0 002dh mccbcr reset value000000 bc1 0 bc0 0 1
st7232a 54/154 10.3 16-bit timer 10.3.1 introduction the timer consists of a 16-bit free-running counter driven by a programmable prescaler. it may be used for a variety of purposes, including pulse length measurement of up to two input sig- nals ( input capture ) or generation of up to two out- put waveforms ( output compare and pwm ). pulse lengths and waveform periods can be mod- ulated from a few micros econds to several milli- seconds using the timer prescaler and the cpu clock prescaler. some st7 devices have two on-chip 16-bit timers. they are completely independent, and do not share any resources. they are synchronized after a mcu reset as long as the timer clock frequen- cies are not modified. this description covers one or two 16-bit timers. in st7 devices with two timers, register names are prefixed with ta (timer a) or tb (timer b). 10.3.2 main features programmable prescaler: f cpu divided by 2, 4 or 8. overflow status flag and maskable interrupt external clock input (must be at least 4 times slower than the cpu clock speed) with the choice of active edge 1 or 2 output compare functions each with: ? 2 dedicated 16-bit registers ? 2 dedicated programmable signals ? 2 dedicated status flags ? 1 dedicated maskable interrupt 1 or 2 input capture functions each with: ? 2 dedicated 16-bit registers ? 2 dedicated active edge selection signals ? 2 dedicated status flags ? 1 dedicated maskable interrupt pulse width modulation mode (pwm) one pulse mode reduced power mode 5 alternate functions on i/o ports (icap1, icap2, ocmp1, ocmp2, extclk)* the block diagram is shown in figure 32 . *note: some timer pins may not be available (not bonded) in some st7 devices. refer to the device pin out description. when reading an input signal on a non-bonded pin, the value will always be ?1?. 10.3.3 functional description 10.3.3.1 counter the main block of the programmable timer is a 16-bit free running upcounter and its associated 16-bit registers. the 16-bit registers are made up of two 8-bit registers called high & low. counter register (cr): ? counter high register (chr) is the most sig- nificant byte (ms byte). ? counter low register (clr) is the least sig- nificant byte (ls byte). alternate counter register (acr) ? alternate counter high register (achr) is the most significant byte (ms byte). ? alternate counter low register (aclr) is the least significant byte (ls byte). these two read-only 16-bit registers contain the same value but with the difference that reading the aclr register does not clear the tof bit (timer overflow flag), located in the status register, (sr), (see note at the end of paragraph titled 16-bit read sequence). writing in the clr register or aclr register resets the free running counter to the fffch value. both counters have a reset value of fffch (this is the only value which is reloaded in the 16-bit tim- er). the reset value of both counters is also fffch in one pulse mode and pwm mode. the timer clock depends on the clock control bits of the cr2 register, as illustrated in table 16 clock control bits . the value in the counter register re- peats every 131072, 262144 or 524288 cpu clock cycles depending on the cc[1:0] bits. the timer frequency can be f cpu /2, f cpu /4, f cpu /8 or an external frequency. caution: in flash devices, timer a functionality has the following restrictions: ? taoc2hr and taoc2lr registers are write only ? input capture 2 is not implemented ? the corresponding interrupts cannot be used (icf2, ocf2 forced by hardware to zero) 1
st7232a 55/154 16-bit timer (cont?d) figure 32. timer block diagram mcu-peripheral interface counter alternate output compare register output compare edge detect overflow detect circuit 1/2 1/4 1/8 8-bit buffer st7 internal bus latch1 ocmp1 icap1 extclk f cpu timer interrupt icf2 icf1 timd 0 0 ocf2 ocf1 tof pwm oc1e exedg iedg2 cc0 cc1 oc2e opm folv2 icie olvl1 iedg1 olvl2 folv1 ocie toie icap2 latch2 ocmp2 8 8 8 low 16 8 high 16 16 16 16 (control register 1) cr1 (control register 2) cr2 (control/status register) 6 16 8 8 8 8 8 8 high low high high high low low low exedg timer internal bus circuit1 edge detect circuit2 circuit 1 output compare register 2 input capture register 1 input capture register 2 cc[1:0] counter pin pin pin pin pin register register note: if ic, oc and to interrupt requests have separate vectors then the last or is not present (see device interrupt vector table) (see note) csr 1
st7232a 56/154 16-bit timer (cont?d) 16-bit read sequence: (from either the counter register or the alternate counter register). the user must read the ms byte first, then the ls byte value is buffered automatically. this buffered value rema ins unchanged until the 16-bit read sequence is completed, even if the user reads the ms byte several times. after a complete reading sequence, if only the clr register or aclr register are read, they re- turn the ls byte of the count value at the time of the read. whatever the timer mode used (input capture, out- put compare, one pulse mode or pwm mode) an overflow occurs when the counter rolls over from ffffh to 0000h then: ? the tof bit of the sr register is set. ? a timer interrupt is generated if: ? toie bit of the cr1 register is set and ? i bit of the cc register is cleared. if one of these conditions is false, the interrupt re- mains pending to be issued as soon as they are both true. clearing the overflow interrupt request is done in two steps: 1. reading the sr register while the tof bit is set. 2. an access (read or write) to the clr register. notes: the tof bit is not cl eared by accesses to aclr register. the advantage of accessing the aclr register rather than the clr register is that it allows simultaneous use of the overflow function and reading the free running counter at random times (for example, to measure elapsed time) with- out the risk of clearing the tof bit erroneously. the timer is not affected by wait mode. in halt mode, the counter stops counting until the mode is exited. counting then resumes from the previous count (mcu awakened by an interrupt) or from the reset count (mcu awakened by a reset). 10.3.3.2 external clock the external clock (where available) is selected if cc0=1 and cc1=1 in the cr2 register. the status of the exedg bit in the cr2 register determines the type of level transition on the exter- nal clock pin extclk that will trigger the free run- ning counter. the counter is synchron ized with the falling edge of the internal cpu clock. a minimum of four falling edges of the cpu clock must occur between two consecutive active edges of the external clock; thus the external clock fre- quency must be less than a quarter of the cpu clock frequency. is buffered read at t0 read returns the buffered ls byte value at t0 at t0 + ? t other instructions beginning of the sequence sequence completed ls byte ls byte ms byte 1
st7232a 57/154 16-bit timer (cont?d) figure 33. counter timing diagram, internal clock divided by 2 figure 34. counter timing diagram, internal clock divided by 4 figure 35. counter timing diagram, internal clock divided by 8 note: the mcu is in reset state when the internal reset signal is high, when it is low the mcu is running. cpu clock fffd fffe ffff 0000 0001 0002 0003 internal reset timer clock counter register timer overflow flag (tof) fffc fffd 0000 0001 cpu clock internal reset timer clock counter register timer overflow flag (tof) cpu clock internal reset timer clock counter register timer overflow flag (tof) fffc fffd 0000 1
st7232a 58/154 16-bit timer (cont?d) 10.3.3.3 input capture in this section, the index, i , may be 1 or 2 because there are 2 input capture functions in the 16-bit timer. the two 16-bit input capture registers (ic1r and ic2r) are used to latch the value of the free run- ning counter after a transition is detected on the icap i pin (see figure 5). ic i r register is a read-only register. the active transition is software programmable through the iedg i bit of control registers (cr i ). timing resolution is one count of the free running counter: ( f cpu / cc[1:0]). procedure: to use the input capture function select the follow- ing in the cr2 register: ? select the timer clock (cc[1:0]) (see table 16 clock control bits ). ? select the edge of the active transition on the icap2 pin with the iedg2 bit (the icap2 pin must be configured as floating input or input with pull-up without interrupt if this configuration is available). and select the following in the cr1 register: ? set the icie bit to generate an interrupt after an input capture coming from either the icap1 pin or the icap2 pin ? select the edge of the active transition on the icap1 pin with the iedg1 bit (the icap1pin must be configured as floating input or input with pull- up without interrupt if this configuration is availa- ble). when an input capture occurs: ? icf i bit is set. ? the ic i r register contains the value of the free running counter on the active transition on the icap i pin (see figure 37 ). ? a timer interrupt is generated if the icie bit is set and the i bit is cleared in the cc register. other- wise, the interrupt remains pending until both conditions become true. clearing the input capture interrupt request (i.e. clearing the icf i bit) is done in two steps: 1. reading the sr register while the icf i bit is set. 2. an access (read or write) to the ic i lr register. notes: 1. after reading the ic i hr register, transfer of input capture data is inhibited and icf i will never be set until the ic i lr register is also read. 2. the ic i r register contains the free running counter value which corresponds to the most recent input capture. 3. the 2 input capture functions can be used together even if the timer also uses the 2 output compare functions. 4. in one pulse mode and pwm mode only input capture 2 can be used. 5. the alternate inputs (icap1 & icap2) are always directly connected to the timer. so any transitions on these pins activates the input capture function. moreover if one of the icap i pins is configured as an input and the second one as an output, an interrupt can be generated if the user tog- gles the output pin and if the icie bit is set. this can be avoided if the input capture func- tion i is disabled by reading the ic i hr (see note 1). 6. the tof bit can be used with interrupt genera- tion in order to measure events that go beyond the timer range (ffffh). 7. in flash devices, the icap2 registers (taic2hr, taic2lr) are not available on timer a. the corresponding interrupts cannot be used (icf2 is forced by hardware to 0). ms byte ls byte icir ic i hr ic i lr 1
st7232a 59/154 16-bit timer (cont?d) figure 36. input capture block diagram figure 37. input capture timing diagram icie cc0 cc1 16-bit free running counter iedg1 (control register 1) cr1 (control register 2) cr2 icf2 icf1 0 0 0 (status register) sr iedg2 icap1 icap2 edge detect circuit2 16-bit ic1r register ic2r register edge detect circuit1 pin pin ff01 ff02 ff03 ff03 timer clock counter register icapi pin icapi flag icapi register note: the rising edge is the a ctive edge. 1
st7232a 60/154 16-bit timer (cont?d) 10.3.3.4 output compare in this section, the index, i , may be 1 or 2 because there are 2 output compare functions in the 16-bit timer. this function can be used to control an output waveform or indicate when a period of time has elapsed. when a match is found between the output com- pare register and the free running counter, the out- put compare function: ? assigns pins with a prog rammable value if the oc i e bit is set ? sets a flag in the status register ? generates an interrupt if enabled two 16-bit registers output compare register 1 (oc1r) and output compare register 2 (oc2r) contain the value to be compared to the counter register each timer clock cycle. these registers are readable and writable and are not affected by the timer hardware. a reset event changes the oc i r value to 8000h. timing resolution is one count of the free running counter: ( f cpu/ cc[1:0] ). procedure: to use the output compare function, select the fol- lowing in the cr2 register: ? set the oc i e bit if an output is needed then the ocmp i pin is dedicated to the output compare i signal. ? select the timer clock (cc[1:0]) (see table 16 clock control bits ). and select the following in the cr1 register: ? select the olvl i bit to applied to the ocmp i pins after the match occurs. ? set the ocie bit to generate an interrupt if it is needed. when a match is found between ocri register and cr register: ? ocf i bit is set. ? the ocmp i pin takes olvl i bit value (ocmp i pin latch is forced low during reset). ? a timer interrupt is generated if the ocie bit is set in the cr1 register and the i bit is cleared in the cc register (cc). the oc i r register value required for a specific tim- ing application can be calculated using the follow- ing formula: where: ? t = output compare period (in seconds) f cpu = cpu clock frequency (in hertz) presc = timer prescaler factor (2, 4 or 8 de- pending on cc[1:0] bits, see table 16 clock control bits ) if the timer clock is an external clock, the formula is: where: ? t = output compare period (in seconds) f ext = external timer clock frequency (in hertz) clearing the output compare interrupt request (i.e. clearing the ocf i bit) is done by: 1. reading the sr register while the ocf i bit is set. 2. an access (read or write) to the oc i lr register. the following procedure is recommended to pre- vent the ocf i bit from being set between the time it is read and the write to the oc i r register: ? write to the oc i hr register (further compares are inhibited). ? read the sr register (first step of the clearance of the ocf i bit, which may be already set). ? write to the oc i lr register (enables the output compare function and clears the ocf i bit). ms byte ls byte oc i roc i hr oc i lr ? oc i r = ? t * f cpu presc ? oc i r = ? t * f ext 1
st7232a 61/154 16-bit timer (cont?d) notes: 1. after a processor write cycle to the oc i hr reg- ister, the output compare function is inhibited until the oc i lr register is also written. 2. if the oc i e bit is not set, the ocmp i pin is a general i/o port and the olvl i bit will not appear when a match is found but an interrupt could be generated if the ocie bit is set. 3. when the timer clock is f cpu /2, ocf i and ocmp i are set while the counter value equals the oc i r register value (see figure 39 on page 62 ). this behaviour is the same in opm or pwm mode. when the timer clock is f cpu /4, f cpu /8 or in external clock mode, ocf i and ocmp i are set while the counter value equals the oc i r regis- ter value plus 1 (see figure 40 on page 62 ). 4. the output compare functions can be used both for generating external events on the ocmp i pins even if the input capture mode is also used. 5. the value in the 16-bit oc i r register and the olv i bit should be changed after each suc- cessful comparison in order to control an output waveform or establish a new elapsed timeout. 6. in flash devices, the taoc2hr, taoc2lr registers are "write only" in timer a. the corre- sponding event cannot be generated (ocf2 is forced by hardware to 0). forced compare output capability when the folv i bit is set by software, the olvl i bit is copied to the ocmp i pin. the olv i bit has to be toggled in order to toggle the ocmp i pin when it is enabled (oc i e bit=1). the ocf i bit is then not set by hardware, and thus no interrupt request is generated. the folvl i bits have no effect in both one pulse mode and pwm mode. figure 38. output compare block diagram output compare 16-bit circuit oc1r register 16 bit free running counter oc1e cc0 cc1 oc2e olvl1 olvl2 ocie (control register 1) cr1 (control register 2) cr2 0 0 0 ocf2 ocf1 (status register) sr 16-bit 16-bit ocmp1 ocmp2 latch 1 latch 2 oc2r register pin pin folv2 folv1 1
st7232a 62/154 16-bit timer (cont?d) figure 39. output compare timing diagram, f timer =f cpu /2 figure 40. output compare timing diagram, f timer =f cpu /4 internal cpu clock timer clock counter register output compare register i (ocr i ) output compare flag i (ocf i ) ocmp i pin (olvl i =1) 2ed3 2ed0 2ed1 2ed2 2ed3 2ed4 2ecf internal cpu clock timer clock counter register output compare register i (ocr i ) compare register i latch 2ed3 2ed0 2ed1 2ed2 2ed3 2ed4 2ecf ocmp i pin (olvl i =1) output compare flag i (ocf i ) 1
st7232a 63/154 16-bit timer (cont?d) 10.3.3.5 one pulse mode one pulse mode enables the generation of a pulse when an external event occurs. this mode is selected via the opm bit in the cr2 register. the one pulse mode uses the input capture1 function and the output compare1 function. procedure: to use one pulse mode: 1. load the oc1r register with the value corre- sponding to the length of the pulse (see the for- mula in the opposite column). 2. select the following in the cr1 register: ? using the olvl1 bit, select the level to be ap- plied to the ocmp1 pin after the pulse. ? using the olvl2 bit, select the level to be ap- plied to the ocmp1 pin during the pulse. ? select the edge of the active transition on the icap1 pin with the iedg1 bit (the icap1 pin must be configured as floating input). 3. select the following in the cr2 register: ? set the oc1e bit, the ocmp1 pin is then ded- icated to the output compare 1 function. ? set the opm bit. ? select the timer clock cc[1:0] (see table 16 clock control bits ). then, on a valid event on the icap1 pin, the coun- ter is initialized to fffc h and olvl2 bit is loaded on the ocmp1 pin, the icf1 bit is set and the val- ue fffdh is loaded in the ic1r register. because the icf1 bit is set when an active edge occurs, an interrupt can be generated if the icie bit is set. clearing the input capture interrupt request (i.e. clearing the icf i bit) is done in two steps: 1. reading the sr register while the icf i bit is set. 2. an access (read or write) to the ic i lr register. the oc1r register value required for a specific timing application can be calculated using the fol- lowing formula: where: t = pulse period (in seconds) f cpu = cpu clock frequency (in hertz) presc = timer prescaler factor (2, 4 or 8 depend- ing on the cc[1:0] bits, see table 16 clock control bits ) if the timer clock is an external clock the formula is: where: t = pulse period (in seconds) f ext = external timer clock frequency (in hertz) when the value of the counter is equal to the value of the contents of the oc1r register, the olvl1 bit is output on the ocmp1 pin, (see figure 41 ). notes: 1. the ocf1 bit cannot be set by hardware in one pulse mode but the ocf2 bit can generate an output compare interrupt. 2. when the pulse width modulation (pwm) and one pulse mode (opm) bits are both set, the pwm mode is the only active one. 3. if olvl1=olvl2 a co ntinuous signal will be seen on the ocmp1 pin. 4. the icap1 pin can not be used to perform input capture. the icap2 pin can be used to perform input capture (icf2 can be set and ic2r can be loaded) but the user must take care that the counter is reset each time a valid edge occurs on the icap1 pin and icf1 can also generates interrupt if icie is set. 5. when one pulse mode is used oc1r is dedi- cated to this mode. nevertheless oc2r and ocf2 can be used to indicate a period of time has been elapsed but cannot generate an out- put waveform because the level olvl2 is dedi- cated to the one pulse mode. 6. in flash devices, timer a ocf2 bit is forced by hardware to 0. event occurs counter = oc1r ocmp1 = olvl1 when when on icap1 one pulse mode cycle ocmp1 = olvl2 counter is reset to fffch icf1 bit is set icr1 = counter oc i r value = t * f cpu presc - 5 oc i r = t * f ext -5 1
st7232a 64/154 16-bit timer (cont?d) figure 41. one pulse mode timing example figure 42. pulse width modulation mode timi ng example with 2 output compare functions counter fffc fffd fffe 2ed0 2ed1 2ed2 2ed3 fffc fffd olvl2 olvl2 olvl1 icap1 ocmp1 compare1 note: iedg1=1, oc1r=2ed0h, olvl1=0, olvl2=1 01f8 01f8 2ed3 ic1r counter 34e2 34e2 fffc olvl2 olvl2 olvl1 ocmp1 compare2 compare1 compare2 note: oc1r=2ed0h, oc2r=34e2, olvl1=0, olvl2= 1 fffc fffd fffe 2ed0 2ed1 2ed2 1
st7232a 65/154 16-bit timer (cont?d) 10.3.3.6 pulse width modulation mode pulse width modulation (pwm) mode enables the generation of a signal with a frequency and pulse length determined by the value of the oc1r and oc2r registers. pulse width modulation mode uses the complete output compare 1 function plus the oc2r regis- ter, and so this functionality can not be used when pwm mode is activated. in pwm mode, double buffering is implemented on the output compare registers. any new values writ- ten in the oc1r and oc2r registers are taken into account only at the end of the pwm period (oc2) to avoid spikes on the pwm output pin (ocmp1). procedure to use pulse width modulation mode: 1. load the oc2r register with the value corre- sponding to the period of the signal using the formula in the opposite column. 2. load the oc1r register with the value corre- sponding to the period of the pulse if (olvl1=0 and olvl2=1) using the formula in the oppo- site column. 3. select the following in the cr1 register: ? using the olvl1 bit, select the level to be ap- plied to the ocmp1 pin after a successful comparison with the oc1r register. ? using the olvl2 bit, select the level to be ap- plied to the ocmp1 pin after a successful comparison with the oc2r register. 4. select the following in the cr2 register: ? set oc1e bit: the ocmp1 pin is then dedicat- ed to the output compare 1 function. ? set the pwm bit. ? select the timer clock (cc[1:0]) (see table 16 clock control bits ). if olvl1=1 and olvl2=0 the length of the posi- tive pulse is the difference between the oc2r and oc1r registers. if olvl1=olvl2 a conti nuous signal will be seen on the ocmp1 pin. the oc i r register value required for a specific tim- ing application can be calculated using the follow- ing formula: where: t = signal or pulse period (in seconds) f cpu = cpu clock frequency (in hertz) presc = timer prescaler factor (2, 4 or 8 depend- ing on cc[1:0] bits, see table 16 ) if the timer clock is an external clock the formula is: where: t = signal or pulse period (in seconds) f ext = external timer clock frequency (in hertz) the output compare 2 event causes the counter to be initialized to fffch (see figure 42 ) notes: 1. after a write instruction to the oc i hr register, the output compare function is inhibited until the oc i lr register is also written. 2. the ocf1 and ocf2 bits cannot be set by hardware in pwm mode therefore the output compare interrupt is inhibited. 3. the icf1 bit is set by hardware when the coun- ter reaches the oc2r value and can produce a timer interrupt if the icie bit is set and the i bit is cleared. 4. in pwm mode the icap1 pin can not be used to perform input capture because it is discon- nected to the timer. the icap2 pin can be used to perform input capture (icf2 can be set and ic2r can be loaded) but the user must take care that the counter is reset each period and icf1 can also generates interrupt if icie is set. 5. when the pulse width modulation (pwm) and one pulse mode (opm) bits are both set, the pwm mode is the only active one. counter ocmp1 = olvl2 counter = oc2r ocmp1 = olvl1 when when = oc1r pulse width modulation cycle counter is reset to fffch icf1 bit is set oc i r value = t * f cpu presc - 5 oc i r = t * f ext -5 1
st7232a 66/154 16-bit timer (cont?d) 10.3.4 low power modes 10.3.5 interrupts note: the 16-bit timer interrupt events are connected to the same interrupt vector (see interrupts chap- ter). these events generate an interrupt if the corresponding enable control bit is set and the interrupt mask in the cc register is reset (rim instruction). 10.3.6 summary of timer modes 1) see note 4 in section 10.3.3.5 one pulse mode 2) see note 5 and 6 in section 10.3.3.5 one pulse mode 3) see note 4 in section 10.3.3.6 pulse width modulation mode mode description wait no effect on 16-bit timer. timer interrupts cause the device to exit from wait mode. halt 16-bit timer regist ers are frozen. in halt mode, the counter stops counting until halt mode is exited. counting re sumes from the previous count when the mcu is woken up by an interrupt with ?e xit from halt mode? capabi lity or from the counter reset value when the mcu is woken up by a reset. if an input capture event occurs on the icap i pin, the input capture detecti on circuitry is armed. consequent- ly, when the mcu is woken up by an interrupt wi th ?exit from halt mode? capability, the icf i bit is set, and the counter value present when exiting fr om halt mode is captured into the ic i r register. interrupt event event flag enable control bit exit from wait exit from halt input capture 1 event/counter reset in pwm mode icf1 icie yes no input capture 2 event icf2 yes no output compare 1 event (not available in pwm mode) ocf1 ocie yes no output compare 2 event (not available in pwm mode) ocf2 yes no timer overflow event tof toie yes no modes timer resources input capture 1 input capture 2 output compare 1 output compare 2 input capture (1 and/or 2) yes yes 2) yes yes output compare (1 and/or 2) yes yes yes yes one pulse mode no not recommended 1) no partially 2) pwm mode no not recommended 3) no no 1
st7232a 67/154 16-bit timer (cont?d) 10.3.7 register description each timer is associated with three control and status registers, and with six pairs of data registers (16-bit values) relating to the two input captures, the two output compares, the counter and the al- ternate counter. control register 1 (cr1) read/write reset value: 0000 0000 (00h) bit 7 = icie input capture interrupt enable. 0: interrupt is inhibited. 1: a timer interrupt is generated whenever the icf1 or icf2 bit of the sr register is set. bit 6 = ocie output compare interrupt enable. 0: interrupt is inhibited. 1: a timer interrupt is generated whenever the ocf1 or ocf2 bit of the sr register is set. bit 5 = toie timer overflow interrupt enable. 0: interrupt is inhibited. 1: a timer interrupt is enabled whenever the tof bit of the sr register is set. bit 4 = folv2 forced output compare 2. this bit is set and cleared by software. 0: no effect on the ocmp2 pin. 1: forces the olvl2 bit to be copied to the ocmp2 pin, if the oc2e bit is set and even if there is no succes sful comparison. bit 3 = folv1 forced output compare 1. this bit is set and cleared by software. 0: no effect on the ocmp1 pin. 1: forces olvl1 to be copied to the ocmp1 pin, if the oc1e bit is set and even if there is no suc- cessful comparison. bit 2 = olvl2 output level 2. this bit is copied to the ocmp2 pin whenever a successful comparison occurs with the oc2r reg- ister and ocxe is set in the cr2 register. this val- ue is copied to the ocmp1 pin in one pulse mode and pulse width modulation mode. bit 1 = iedg1 input edge 1. this bit determines which type of level transition on the icap1 pin will trigger the capture. 0: a falling edge tr iggers the capture. 1: a rising edge triggers the capture. bit 0 = olvl1 output level 1. the olvl1 bit is copied to the ocmp1 pin when- ever a successful comparison occurs with the oc1r register and the oc1e bit is set in the cr2 register. 70 icie ocie toie folv2 folv1 olvl2 iedg1 olvl1 1
st7232a 68/154 16-bit timer (cont?d) control register 2 (cr2) read/write reset value: 0000 0000 (00h) bit 7 = oc1e output compare 1 pin enable. this bit is used only to output the signal from the timer on the ocmp1 pin (olv1 in output com- pare mode, both olv1 and olv2 in pwm and one-pulse mode). whatever the value of the oc1e bit, the output compare 1 function of the timer re- mains active. 0: ocmp1 pin alternate function disabled (i/o pin free for general-purpose i/o). 1: ocmp1 pin alternate function enabled. bit 6 = oc2e output compare 2 pin enable. this bit is used only to output the signal from the timer on the ocmp2 pin (olv2 in output com- pare mode). whatever the value of the oc2e bit, the output compare 2 function of the timer re- mains active. 0: ocmp2 pin alternate function disabled (i/o pin free for general-purpose i/o). 1: ocmp2 pin alternate function enabled. bit 5 = opm one pulse mode. 0: one pulse mode is not active. 1: one pulse mode is active, the icap1 pin can be used to trigger one pulse on the ocmp1 pin; the active transition is given by the iedg1 bit. the length of the generated pulse depends on the contents of the oc1r register. bit 4 = pwm pulse width modulation. 0: pwm mode is not active. 1: pwm mode is active, the ocmp1 pin outputs a programmable cyclic signal; the length of the pulse depends on the value of oc1r register; the period depends on the value of oc2r regis- ter. bit 3, 2 = cc[1:0] clock control. the timer clock mode depends on these bits: table 16. clock control bits note : if the external clock pi n is not available, pro- gramming the external clock configuration stops the counter. bit 1 = iedg2 input edge 2. this bit determines which type of level transition on the icap2 pin will trigger the capture. 0: a falling edge tr iggers the capture. 1: a rising edge triggers the capture. bit 0 = exedg external clock edge. this bit determines which type of level transition on the external clock pin extclk will trigger the counter register. 0: a falling edge triggers the counter register. 1: a rising edge triggers the counter register. 70 oc1e oc2e opm pwm cc1 cc0 iedg2 exedg timer clock cc1 cc0 f cpu / 4 0 0 f cpu / 2 0 1 f cpu / 8 1 0 external clock (where available) 11 1
st7232a 69/154 16-bit timer (cont?d) control/status register (csr) read only (except bit 2 r/w) reset value: xxxx x0xx (xxh) bit 7 = icf1 input capture flag 1. 0: no input capture (reset value). 1: an input capture has occurred on the icap1 pin or the counter has reached the oc2r value in pwm mode. to clear this bit, first read the sr register, then read or write the low byte of the ic1r (ic1lr) register. bit 6 = ocf1 output compare flag 1. 0: no match (reset value). 1: the content of the free running counter has matched the content of the oc1r register. to clear this bit, first read the sr register, then read or write the low byte of the oc1r (oc1lr) reg- ister. bit 5 = tof timer overflow flag. 0: no timer overflow (reset value). 1: the free running counter rolled over from ffffh to 0000h. to clear this bit, first read the sr reg- ister, then read or write the low byte of the cr (clr) register. note: reading or writing the aclr register does not clear tof. bit 4 = icf2 input capture flag 2. 0: no input capture (reset value). 1: an input capture has occurred on the icap2 pin. to clear this bit, first read the sr register, then read or write the low byte of the ic2r (ic2lr) register. bit 3 = ocf2 output compare flag 2. 0: no match (reset value). 1: the content of the free running counter has matched the content of the oc2r register. to clear this bit, first read the sr register, then read or write the low byte of the oc2r (oc2lr) reg- ister. bit 2 = timd timer disable. this bit is set and cleared by software. when set, it freezes the timer prescaler and counter and disa- bled the output functions (ocmp1 and ocmp2 pins) to reduce power cons umption. access to the timer registers is still ava ilable, allowing the timer configuration to be changed, or the counter reset, while it is disabled. 0: timer enabled 1: timer prescaler, counter and outputs disabled bits 1:0 = reserved, mu st be kept cleared. 70 icf1 ocf1 tof icf2 ocf2 timd 0 0 1
st7232a 70/154 16-bit timer (cont?d) input capture 1 high register (ic1hr) read only reset value: undefined this is an 8-bit read only register that contains the high part of the counter value (transferred by the input capture 1 event). input capture 1 low register (ic1lr) read only reset value: undefined this is an 8-bit read only register that contains the low part of the counter value (transferred by the in- put capture 1 event). output compare 1 high register (oc1hr) read/write reset value: 1000 0000 (80h) this is an 8-bit register that contains the high part of the value to be compared to the chr register. output compare 1 low register (oc1lr) read/write reset value: 0000 0000 (00h) this is an 8-bit register that contains the low part of the value to be compared to the clr register. 70 msb lsb 70 msb lsb 70 msb lsb 70 msb lsb 1
st7232a 71/154 16-bit timer (cont?d) output compare 2 high register (oc2hr) read/write reset value: 1000 0000 (80h) this is an 8-bit register that contains the high part of the value to be compared to the chr register. output compare 2 low register (oc2lr) read/write reset value: 0000 0000 (00h) this is an 8-bit register that contains the low part of the value to be compared to the clr register. counter high register (chr) read only reset value: 1111 1111 (ffh) this is an 8-bit register that contains the high part of the counter value. counter low register (clr) read only reset value: 1111 1100 (fch) this is an 8-bit register that contains the low part of the counter value. a write to this register resets the counter. an access to this register after accessing the csr register clears the tof bit. 70 msb lsb 70 msb lsb 70 msb lsb 70 msb lsb 1
st7232a 72/154 16-bit timer (cont?d) alternate counter high register (achr) read only reset value: 1111 1111 (ffh) this is an 8-bit register that contains the high part of the counter value. alternate counter low register (aclr) read only reset value: 1111 1100 (fch) this is an 8-bit register that contains the low part of the counter value. a write to this register resets the counter. an access to this register after an access to csr register does not clear the tof bit in the csr register. input capture 2 high register (ic2hr) read only reset value: undefined this is an 8-bit read only register that contains the high part of the counter value (transferred by the input capture 2 event). input capture 2 low register (ic2lr) read only reset value: undefined this is an 8-bit read only register that contains the low part of the counter value (transferred by the in- put capture 2 event). 70 msb lsb 70 msb lsb 70 msb lsb 70 msb lsb 1
st7232a 73/154 16-bit timer (cont?d) table 17. 16-bit timer register map and reset values address (hex.) register label 76543210 timer a: 32 timer b: 42 cr1 reset value icie 0 ocie 0 toie 0 folv2 0 folv1 0 olvl2 0 iedg1 0 olvl1 0 timer a: 31 timer b: 41 cr2 reset value oc1e 0 oc2e 0 opm 0 pwm 0 cc1 0 cc0 0 iedg2 0 exedg 0 timer a: 33 timer b: 43 csr reset value icf1 x ocf1 x tof x icf2 x ocf2 x timd 0 - x - x timer a: 34 timer b: 44 ic1hr reset value msb xxxxxxx lsb x timer a: 35 timer b: 45 ic1lr reset value msb xxxxxxx lsb x timer a: 36 timer b: 46 oc1hr reset value msb 1000000 lsb 0 timer a: 37 timer b: 47 oc1lr reset value msb 0000000 lsb 0 timer a: 3e timer b: 4e oc2hr reset value msb 1000000 lsb 0 timer a: 3f timer b: 4f oc2lr reset value msb 0000000 lsb 0 timer a: 38 timer b: 48 chr reset value msb 1111111 lsb 1 timer a: 39 timer b: 49 clr reset value msb 1111110 lsb 0 timer a: 3a timer b: 4a achr reset value msb 1111111 lsb 1 timer a: 3b timer b: 4b aclr reset value msb 1111110 lsb 0 timer a: 3c timer b: 4c ic2hr reset value msb xxxxxxx lsb x timer a: 3d timer b: 4d ic2lr reset value msb xxxxxxx lsb x 1
st7232a 74/154 10.4 serial peripheral interface (spi) 10.4.1 introduction the serial peripheral interface (spi) allows full- duplex, synchronous, serial communication with external devices. an spi system may consist of a master and one or more slaves however the spi interface can not be a master in a multi-master system. 10.4.2 main features full duplex synchronous transfers (on 3 lines) simplex synchronous transfers (on 2 lines) master or slave operation six master mode frequencies (f cpu /4 max.) f cpu /2 max. slave mode frequency (see note) ss management by software or hardware programmable clock polarity and phase end of transfer interrupt flag write collision, master mode fault and overrun flags note: in slave mode, continuous transmission is not possible at maximum frequency due to the software overhead for clearing status flags and to initiate the next transmission sequence. 10.4.3 general description figure 43 shows the serial peripheral interface (spi) block diagram. there are 3 registers: ? spi control register (spicr) ? spi control/status register (spicsr) ? spi data register (spidr) the spi is connected to external devices through 4 pins: ? miso: master in / slave out data ? mosi: master out / slave in data ? sck: serial clock out by spi masters and in- put by spi slaves figure 43. serial peripheral interface block diagram spidr read buffer 8-bit shift register write read data/address bus spi spie spe mstr cpha spr0 spr1 cpol serial clock generator mosi miso ss sck control state spicr spicsr interrupt request master control spr2 0 7 0 7 spif wcol modf 0 ovr ssi ssm sod sod bit ss 1 0 1
st7232a 75/154 serial peripheral interface (cont?d) ?ss : slave select: this input signal acts as a ?chip select? to let the spi master communicate with slaves indi- vidually and to avoid contention on the data lines. slave ss inputs can be driven by stand- ard i/o ports on the master mcu. 10.4.3.1 functional description a basic example of inte rconnections between a single master and a sing le slave is illustrated in figure 44 . the mosi pins are connected together and the miso pins are connected together. in this way data is transferred serially between master and slave (most significant bit first). the communication is always initiated by the mas- ter. when the master device transmits data to a slave device via mosi pin, the slave device re- sponds by sending data to the master device via the miso pin. this imp lies full duplex communica- tion with both data out and data in synchronized with the same clock signal (which is provided by the master device via the sck pin). to use a single data line, the miso and mosi pins must be connected at each node ( in this case only simplex communication is possible). four possible data/clock timing relationships may be chosen (see figure 47 ) but master and slave must be programmed with the same timing mode. figure 44. single master/ single slave application 8-bit shift register spi clock generator 8-bit shift register miso mosi mosi miso sck sck slave master ss ss +5v msbit lsbit msbit lsbit not used if ss is managed by software 1
st7232a 76/154 serial peripheral interface (cont?d) 10.4.3.2 slave select management as an alternative to using the ss pin to control the slave select signal, the application can choose to manage the slave select signal by software. this is configured by the ssm bit in the spicsr regis- ter (see figure 46 ) in software management, the external ss pin is free for other application uses and the internal ss signal level is driven by writing to the ssi bit in the spicsr register. in master mode: ?ss internal must be held high continuously in slave mode: there are two cases depending on the data/clock timing relationship (see figure 45 ): if cpha=1 (data latched on 2nd clock edge): ?ss internal must be held low during the entire transmission. this implies that in single slave applications the ss pin either can be tied to v ss , or made free for standard i/o by manag- ing the ss function by software (ssm= 1 and ssi=0 in the in the spicsr register) if cpha=0 (data latched on 1st clock edge): ?ss internal must be held low during byte transmission and pulled high between each byte to allow the slave to write to the shift reg- ister. if ss is not pulled high, a write collision error will occur when the slave writes to the shift register (see section 10.4.5.3 ). figure 45. generic ss timing diagram figure 46. hardware/software slave select management mosi/miso master ss slave ss (if cpha=0) slave ss (if cpha=1) byte 1 byte 2 byte 3 1 0 ss internal ssm bit ssi bit ss external pin 1
st7232a 77/154 serial peripheral interface (cont?d) 10.4.3.3 master mode operation in master mode, the serial clock is output on the sck pin. the clock frequency, polarity and phase are configured by software (refer to the description of the spicsr register). note: the idle state of sck must correspond to the polarity selected in the spicsr register (by pulling up sck if cpol=1 or pulling down sck if cpol=0). to operate the spi in master mode, perform the following steps in order (i f the spicsr register is not written first, the spicr register setting (mstr bit) may be not taken into account): 1. write to the spicr register: ? select the clock frequency by configuring the spr[2:0] bits. ? select the clock polarity and clock phase by configuring the cpol and cpha bits. figure 47 shows the four possible configurations. note: the slave must have the same cpol and cpha settings as the master. 2. write to the spicsr register: ? either set the ssm bit and set the ssi bit or clear the ssm bit and tie the ss pin high for the complete byte transmit sequence. 3. write to the spicr register: ? set the mstr and spe bits note: mstr and spe bits remain set only if ss is high). the transmit sequence begins when software writes a byte in the spidr register. 10.4.3.4 master mode transmit sequence when software writes to the spidr register, the data byte is loaded into the 8-bit shift register and then shifted out serially to the mosi pin most sig- nificant bit first. when data transfer is complete: ? the spif bit is set by hardware ? an interrupt request is generated if the spie bit is set and the interrupt mask in the ccr register is cleared. clearing the spif bit is performed by the following software sequence: 1. an access to the spicsr register while the spif bit is set 2. a read to the spidr register. note: while the spif bit is se t, all writes to the spidr register are inhibited until the spicsr reg- ister is read. 10.4.3.5 slave mode operation in slave mode, the serial clock is received on the sck pin from the master device. to operate the spi in slave mode: 1. write to the spicsr register to perform the fol- lowing actions: ? select the clock polarity and clock phase by configuring the cpol and cpha bits (see figure 47 ). note: the slave must have the same cpol and cpha settings as the master. ? manage the ss pin as described in section 10.4.3.2 and figure 45 . if cpha=1 ss must be held low continuously. if cpha=0 ss must be held low during byte transmission and pulled up between each byte to let the slave write in the shift register. 2. write to the spicr register to clear the mstr bit and set the spe bit to enable the spi i/o functions. 10.4.3.6 slave mode transmit sequence when software writes to the spidr register, the data byte is loaded into the 8-bit shift register and then shifted out serially to the miso pin most sig- nificant bit first. the transmit sequence begins when the slave de- vice receives the clock signal and the most signifi- cant bit of the data on its mosi pin. when data transfer is complete: ? the spif bit is set by hardware ? an interrupt request is generated if spie bit is set and interrupt mask in the ccr register is cleared. clearing the spif bit is performed by the following software sequence: 1. an access to the spics r register while the spif bit is set. 2. a write or a read to the spidr register. notes: while the spif bit is set, all writes to the spidr register are inhibited until the spicsr reg- ister is read. the spif bit can be cleared during a second transmission; however, it must be cleared before the second spif bit in order to prevent an overrun condition (see section 10.4.5.2 ). 1
st7232a 78/154 serial peripheral interface (cont?d) 10.4.4 clock phase and clock polarity four possible timing relationships may be chosen by software, using the cpol and cpha bits (see figure 47 ). note: the idle state of sck must correspond to the polarity selected in the spicsr register (by pulling up sck if cpol=1 or pulling down sck if cpol=0). the combination of the cpol clock polarity and cpha (clock phase) bits selects the data capture clock edge figure 47 , shows an spi transfer with the four combinations of the cpha and cpol bits. the di- agram may be interpreted as a master or slave timing diagram where the sck pin, the miso pin, the mosi pin are directly connected between the master and the slave device. note : if cpol is changed at the communication byte boundaries, the spi must be disabled by re- setting the spe bit. figure 47. data clock timing diagram sck msbit bit 6 bit 5 bit 4 bit3 bit 2 bit 1 lsbit msbit bit 6 bit 5 bit 4 bit3bit 2bit 1lsbit miso (from master) mosi (from slave) ss (to slave) capture strobe cpha =1 msbit bit 6 bit 5 bit 4 bit3 bit 2 bit 1 lsbit msbit bit 6 bit 5 bit 4 bit3 bit 2 bit 1 lsbit miso (from master) mosi ss (to slave) capture strobe cpha =0 note: this figure should not be used as a replacement for parametric information. refer to the electrical characteristics chapter. (from slave) (cpol = 1) sck (cpol = 0) sck (cpol = 1) sck (cpol = 0) 1
st7232a 79/154 serial peripheral interface (cont?d) 10.4.5 error flags 10.4.5.1 master mode fault (modf) master mode fault occurs when the master device has its ss pin pulled low. when a master mode fault occurs: ? the modf bit is set and an spi interrupt re- quest is generated if the spie bit is set. ? the spe bit is reset. this blocks all output from the device and disables the spi periph- eral. ? the mstr bit is reset, thus forcing the device into slave mode. clearing the modf bit is done through a software sequence: 1. a read access to the spicsr register while the modf bit is set. 2. a write to the spicr register. notes: to avoid any conflicts in an application with multiple slaves, the ss pin must be pulled high during the modf bit clearing sequence. the spe and mstr bits may be restored to their orig- inal state during or after this clearing sequence. hardware does not allow the user to set the spe and mstr bits while the modf bit is set except in the modf bit clearing sequence. 10.4.5.2 overrun condition (ovr) an overrun condition occurs, when the master de- vice has sent a data byte and the slave device has not cleared the spif bit issued from the previously transmitted byte. when an overrun occurs: ? the ovr bit is set and an interrupt request is generated if the spie bit is set. in this case, the receiver buffer contains the byte sent after the spif bit was last cleared. a read to the spidr register returns this byte. all other bytes are lost. the ovr bit is cleared by reading the spicsr register. 10.4.5.3 write collision error (wcol) a write collision occurs when the software tries to write to the spidr register while a data transfer is taking place with an external device. when this happens, the transfer continues uninterrupted; and the software write will be unsuccessful. write collisions can occur both in master and slave mode. see also section 10.4.3.2 slave select management . note: a "read collision" will never occur since the received data byte is placed in a buffer in which access is always synchronous with the mcu oper- ation. the wcol bit in the spicsr register is set if a write collision occurs. no spi interrupt is generated when the wcol bit is set (the wcol bit is a status flag only). clearing the wcol bit is done through a software sequence (see figure 48 ). figure 48. clearing the wcol bit (write collision flag) software sequence clearing sequence after spif = 1 (end of a data byte transfer) 1st step read spicsr read spidr 2nd step spif =0 wcol=0 clearing sequence before spif = 1 (during a data byte transfer) 1st step 2nd step wcol=0 read spicsr read spidr note: writing to the spidr regis- ter instead of reading it does not reset the wcol bit result result 1
st7232a 80/154 serial peripheral interface (cont?d) 10.4.5.4 single master systems a typical single master system may be configured, using an mcu as the master and four mcus as slaves (see figure 49 ). the master device selects the individual slave de- vices by using four pins of a parallel port to control the four ss pins of the slave devices. the ss pins are pulled high during reset since the master device ports will be forced to be inputs at that time, thus disabling the slave devices. note: to prevent a bus conflict on the miso line the master allows only one active slave device during a transmission. for more security, the slave device may respond to the master with the received data byte. then the master will receive the previo us byte back from the slave device if all miso and mosi pins are con- nected and the slave has not written to its spidr register. other transmission security methods can use ports for handshake lines or data bytes with com- mand fields. figure 49. single master / multiple slave configuration miso mosi mosi mosi mosi mosi miso miso miso miso ss ss ss ss ss sck sck sck sck sck 5v ports slave mcu slave mcu slave mcu slave mcu master mcu 1
st7232a 81/154 serial peripheral interface (cont?d) 10.4.6 low power modes 10.4.6.1 using the spi to wakeup the mcu from halt mode in slave configuration, the spi is able to wakeup the st7 device from halt mode through a spif interrupt. the data received is subsequently read from the spidr register when the software is run- ning (interrupt vector fetch). if multiple data trans- fers have been performed before software clears the spif bit, then the ovr bit is set by hardware. note: when waking up from halt mode, if the spi remains in slave mode, it is recommended to per- form an extra communications cycle to bring the spi from halt mode state to normal state. if the spi exits from slave mode, it returns to normal state immediately. caution: the spi can wake up the st7 from halt mode only if the slave select signal (external ss pin or the ssi bit in the spicsr register) is low when the st7 enters halt mode. so if slave selec- tion is configured as external (see section 10.4.3.2 ), make sure the master drives a low level on the ss pin when the slave enters halt mode. 10.4.7 interrupts note : the spi interrupt events are connected to the same interrupt vector (see interrupts chapter). they generate an interrupt if the corresponding enable control bit is set and the interrupt mask in mode description wait no effect on spi. spi interrupt events cause the device to exit from wait mode. halt spi registers are frozen. in halt mode, the spi is inactive. spi oper- ation resumes when the mcu is woken up by an interrupt with ?exit from halt mode? ca- pability. the data received is subsequently read from the spidr r egister when the soft- ware is running (interrupt vector fetching). if several data are received before the wake- up event, then an overru n error is generated. this error can be detected after the fetch of the interrupt routine t hat woke up the device. interrupt event event flag enable control bit exit from wait exit from halt spi end of transfer event spif spie yes yes master mode fault event modf yes no overrun error ovr yes no 1
st7232a 82/154 serial peripheral interface (cont?d) 10.4.8 register description control register (spicr) read/write reset value: 0000 xxxx (0xh) bit 7 = spie serial peripheral interrupt enable. this bit is set and cleared by software. 0: interrupt is inhibited 1: an spi interrupt is generated whenever spif=1, modf=1 or ovr=1 in the spicsr register bit 6 = spe serial peripheral output enable. this bit is set and cleared by software. it is also cleared by hardware when, in master mode, ss =0 (see section 10.4.5.1 master mode fault (modf) ). the spe bit is cleared by reset, so the spi peripheral is not initia lly connected to the ex- ternal pins. 0: i/o pins free for general purpose i/o 1: spi i/o pin alternate functions enabled bit 5 = spr2 divider enable . this bit is set and cleared by software and is cleared by reset. it is used with the spr[1:0] bits to set the baud rate. refer to table 18 spi master mode sck frequency . 0: divider by 2 enabled 1: divider by 2 disabled note: this bit has no effect in slave mode. bit 4 = mstr master mode. this bit is set and cleared by software. it is also cleared by hardware when, in master mode, ss =0 (see section 10.4.5.1 master mode fault (modf) ). 0: slave mode 1: master mode. the function of the sck pin changes from an input to an output and the func- tions of the miso and mosi pins are reversed. bit 3 = cpol clock polarity. this bit is set and cleared by software. this bit de- termines the idle state of the serial clock. the cpol bit affects both the master and slave modes. 0: sck pin has a low level idle state 1: sck pin has a high level idle state note : if cpol is changed at the communication byte boundaries, the spi must be disabled by re- setting the spe bit. bit 2 = cpha clock phase. this bit is set and cleared by software. 0: the first clock transition is the first data capture edge. 1: the second clock transition is the first capture edge. note: the slave must have the same cpol and cpha settings as the master. bits 1:0 = spr[1:0] serial clock frequency. these bits are set and cleared by software. used with the spr2 bit, they select the baud rate of the spi serial clock sck output by the spi in master mode. note: these 2 bits have no effect in slave mode. table 18. spi master mode sck frequency 70 spie spe spr2 mstr cpol cpha spr1 spr0 serial clock spr2 spr1 spr0 f cpu /4 1 0 0 f cpu /8 0 0 0 f cpu /16 0 0 1 f cpu /32 1 1 0 f cpu /64 0 1 0 f cpu /128 0 1 1 1
st7232a 83/154 serial peripheral interface (cont?d) control/status register (spicsr) read/write (some bits read only) reset value: 0000 0000 (00h) bit 7 = spif serial peripheral data transfer flag (read only). this bit is set by hardware when a transfer has been completed. an interrupt is generated if spie=1 in the spicr regist er. it is cleared by a software sequence (an access to the spicsr register followed by a write or a read to the spidr register). 0: data transfer is in progress or the flag has been cleared. 1: data transfer between the device and an exter- nal device has been completed. note: while the spif bit is se t, all writes to the spidr register are inhibited until the spicsr reg- ister is read. bit 6 = wcol write collision stat us (read only). this bit is set by hardware when a write to the spidr register is done during a transmit se- quence. it is cleared by a software sequence (see figure 48 ). 0: no write collision occurred 1: a write collision has been detected bit 5 = ovr s pi overrun error (read only). this bit is set by hardware when the byte currently being received in the shift register is ready to be transferred into the spidr register while spif = 1 (see section 10.4.5.2 ). an interrupt is generated if spie = 1 in spicr register. the ovr bit is cleared by software reading the spicsr register. 0: no overrun error 1: overrun error detected bit 4 = modf mode fault flag (read only). this bit is set by hardware when the ss pin is pulled low in master mode (see section 10.4.5.1 master mode fault (modf) ). an spi interrupt can be generated if spie=1 in the spicsr register. this bit is cleared by a software sequence (an ac- cess to the spicr register while modf=1 fol- lowed by a write to the spicr register). 0: no master mode fault detected 1: a fault in master mode has been detected bit 3 = reserved, must be kept cleared. bit 2 = sod spi output disable. this bit is set and cleared by software. when set, it disables the alternate function of the spi output (mosi in master mode / miso in slave mode) 0: spi output enabled (if spe=1) 1: spi output disabled bit 1 = ssm ss management. this bit is set and cleared by software. when set, it disables the alternate function of the spi ss pin and uses the ssi bit value instead. see section 10.4.3.2 slave select management . 0: hardware management (ss managed by exter- nal pin) 1: software management (internal ss signal con- trolled by ssi bit. external ss pin free for gener- al-purpose i/o) bit 0 = ssi ss internal mode. this bit is set and cleared by software. it acts as a ?chip select? by controlling the level of the ss slave select signal when the ssm bit is set. 0 : slave selected 1 : slave deselected data i/o register (spidr) read/write reset value: undefined the spidr register is used to transmit and receive data on the serial bus. in a master device, a write to this register will init iate transmission/reception of another byte. notes: during the last clock cycle the spif bit is set, a copy of the received data byte in the shift register is moved to a buffer. when the user reads the serial peripheral data i/o register, the buffer is actually being read. while the spif bit is set, all writes to the spidr register are inhibited until the spicsr register is read. warning: a write to the spidr register places data directly into the shift register for transmission. a read to the spidr register returns the value lo- cated in the buffer and not the content of the shift register (see figure 43 ). 70 spif wcol ovr modf - sod ssm ssi 70 d7 d6 d5 d4 d3 d2 d1 d0 1
st7232a 84/154 serial peripheral interface (cont?d) table 19. spi register map and reset values address (hex.) register label 76543210 0021h spidr reset value msb xxxxxxx lsb x 0022h spicr reset value spie 0 spe 0 spr2 0 mstr 0 cpol x cpha x spr1 x spr0 x 0023h spicsr reset value spif 0 wcol 0 or 0 modf 00 sod 0 ssm 0 ssi 0 1
st7232a 85/154 10.5 serial communications interface (sci) 10.5.1 introduction the serial communications interface (sci) offers a flexible means of full-duplex data exchange with external equipment requiring an industry standard nrz asynchronous serial data format. the sci of- fers a very wide range of baud rates using two baud rate generator systems. 10.5.2 main features full duplex, asynchronous communications nrz standard format (mark/space) dual baud rate generator systems independently programmable transmit and receive baud rates up to 500k baud. programmable data word length (8 or 9 bits) receive buffer full, transmit buffer empty and end of transmission flags two receiver wake-up modes: ? address bit (msb) ? idle line muting function for multiprocessor configurations separate enable bits for transmitter and receiver four error detection flags: ? overrun error ? noise error ? frame error ? parity error five interrupt sources with flags: ? transmit data register empty ? transmission complete ? receive data register full ? idle line received ? overrun error detected parity control: ? transmits parity bit ? checks parity of received data byte reduced power consumption mode 10.5.3 general description the interface is externally connected to another device by two pins (see figure 51 ): ? tdo: transmit data output. when the transmit- ter and the receiver are disabled, the output pin returns to its i/o port configuration. when the transmitter and/or the receiver are enabled and nothing is to be transmitted, the tdo pin is at high level. ? rdi: receive data input is the serial data input. oversampling techniques are used for data re- covery by discriminating between valid incoming data and noise. through these pins, serial data is transmitted and received as frames comprising: ? an idle line prior to transmission or reception ? a start bit ? a data word (8 or 9 bits) least significant bit first ? a stop bit indicating that the frame is complete. this interface uses two types of baud rate generator: ? a conventional type for commonly-used baud rates, ? an extended type with a prescaler offering a very wide range of baud rates even with non-standard oscillator frequencies. 1
st7232a 86/154 serial communications interface (cont?d) figure 50. sci block diagram wake up unit receiver control sr transmit control tdre tc rdrf idle or nf fe pe sci control interrupt cr1 r8 t8 scid m wake pce ps pie received data register (rdr) received shift register read transmit data register (tdr) transmit shift register write rdi tdo (data register) dr transmitter clock receiver clock receiver rate transmitter rate brr scp1 f cpu control control scp0 sct2 sct1 sct0 scr2 scr1scr0 /pr /16 conventional baud rate generator sbk rwu re te ilie rie tcie tie cr2 1
st7232a 87/154 serial communications interface (cont?d) 10.5.4 functional description the block diagram of the serial control interface, is shown in figure 50 . it contains 6 dedicated reg- isters: ? two control registers (scicr1 & scicr2) ? a status register (scisr) ? a baud rate register (scibrr) ? an extended prescaler receiver register (scier- pr) ? an extended prescaler transmitter register (sci- etpr) refer to the register descriptions in section 10.5.7 for the definitions of each bit. 10.5.4.1 serial data format word length may be selected as being either 8 or 9 bits by programming the m bit in the scicr1 reg- ister (see figure 50 ). the tdo pin is in low state during the start bit. the tdo pin is in high state during the stop bit. an idle character is interpreted as an entire frame of ?1?s followed by the start bit of the next frame which contains data. a break character is interpreted on receiving ?0?s for some multiple of the frame period. at the end of the last break frame the transmitter inserts an ex- tra ?1? bit to acknowledge the start bit. transmission and reception are driven by their own baud rate generator. figure 51. word length programming bit0 bit1 bit2 bit3 bit4 bit5 bit6 bit7 bit8 start bit stop bit next start bit idle frame bit0 bit1 bit2 bit3 bit4 bit5 bit6 bit7 start bit stop bit next start bit start bit idle frame start bit 9-bit word length (m bit is set) 8-bit word length (m bit is reset) possible parity bit possible parity bit break frame start bit extra ?1? data frame break frame start bit extra ?1? data frame next data frame next data frame 1
st7232a 88/154 serial communications interface (cont?d) 10.5.4.2 transmitter the transmitter can send data words of either 8 or 9 bits depending on the m bit status. when the m bit is set, word length is 9 bits and the 9th bit (the msb) has to be stored in the t8 bit in the scicr1 register. character transmission during an sci transmission, data shifts out least significant bit first on the tdo pin. in this mode, the scidr register consists of a buffer (tdr) be- tween the internal bus and the transmit shift regis- ter (see figure 50 ). procedure ? select the m bit to define the word length. ? select the desired baud rate using the scibrr and the scietpr registers. ? set the te bit to assign the tdo pin to the alter- nate function and to send a idle frame as first transmission. ? access the scisr register and write the data to send in the scidr register (this sequence clears the tdre bit). repeat this sequence for each data to be transmitted. clearing the tdre bit is always performed by the following software sequence: 1. an access to the scisr register 2. a write to the scidr register the tdre bit is set by hardware and it indicates: ? the tdr register is empty. ? the data transfer is beginning. ? the next data can be written in the scidr regis- ter without overwriting the previous data. this flag generates an interrupt if the tie bit is set and the i bit is cleared in the ccr register. when a transmission is taking place, a write in- struction to the scidr register stores the data in the tdr register and which is copied in the shift register at the end of the current transmission. when no transmission is taking place, a write in- struction to the scidr register places the data di- rectly in the shift register, the data transmission starts, and the tdre bit is immediately set. when a frame transmission is complete (after the stop bit or after the break frame) the tc bit is set and an interrupt is generated if the tcie is set and the i bit is cleared in the ccr register. clearing the tc bit is performed by the following software sequence: 1. an access to the scisr register 2. a write to the scidr register note: the tdre and tc bits are cleared by the same software sequence. break characters setting the sbk bit loads the shift register with a break character. the break frame length depends on the m bit (see figure 51 ). as long as the sbk bit is set, the sci send break frames to the tdo pin. after clearing this bit by software the sci insert a logic 1 bit at the end of the last break frame to guarantee the recognition of the start bit of the next frame. idle characters setting the te bit drives the sci to send an idle frame before the first data frame. clearing and then setting the te bit during a trans- mission sends an idle frame after the current word. note: resetting and setting the te bit causes the data in the tdr register to be lost. therefore the best time to toggle the te bit is when the tdre bit is set i.e. before writing the next byte in the scidr. 1
st7232a 89/154 serial communications interface (cont?d) 10.5.4.3 receiver the sci can receive data words of either 8 or 9 bits. when the m bit is set, word length is 9 bits and the msb is stored in the r8 bit in the scicr1 register. character reception during a sci reception, data shifts in least signifi- cant bit first through the rdi pin. in this mode, the scidr register consists or a buffer (rdr) be- tween the internal bus and the received shift regis- ter (see figure 50 ). procedure ? select the m bit to define the word length. ? select the desired baud rate using the scibrr and the scierpr registers. ? set the re bit, this enables the receiver which begins searching for a start bit. when a character is received: ? the rdrf bit is set. it indicates that the content of the shift register is transferred to the rdr. ? an interrupt is generated if the rie bit is set and the i bit is cleared in the ccr register. ? the error flags can be set if a frame error, noise or an overrun error has been detected during re- ception. clearing the rdrf bit is performed by the following software sequence done by: 1. an access to the scisr register 2. a read to the scidr register. the rdrf bit must be cleared before the end of the reception of the next character to avoid an overrun error. break character when a break character is received, the spi han- dles it as a framing error. idle character when a idle frame is detected, there is the same procedure as a data received character plus an in- terrupt if the ilie bit is set and the i bit is cleared in the ccr register. overrun error an overrun error occurs when a character is re- ceived when rdrf has not been reset. data can not be transferred from the shift register to the rdr register as long as the rdrf bit is not cleared. when a overrun error occurs: ? the or bit is set. ? the rdr content will not be lost. ? the shift register will be overwritten. ? an interrupt is generated if the rie bit is set and the i bit is cleared in the ccr register. the or bit is reset by an access to the scisr reg- ister followed by a scidr register read operation. noise error oversampling techniques are used for data recov- ery by discriminating between valid incoming data and noise. normal data bits are considered valid if three consecutive samples (8th, 9th, 10th) have the same bit value, otherwise the nf flag is set. in the case of start bit detection, the nf flag is set on the basis of an algorithm combining both valid edge detection and three samples (8th, 9th, 10th). therefore, to prevent the nf flag getting set during start bit reception, there should be a valid edge de- tection as well as three valid samples. when noise is detected in a frame: ? the nf flag is set at the rising edge of the rdrf bit. ? data is transferred from the shift register to the scidr register. ? no interrupt is generated. however this bit rises at the same time as th e rdrf bit which itself generates an interrupt. the nf flag is reset by a scisr register read op- eration followed by a scidr register read opera- tion. during reception, if a false start bit is detected (e.g. 8th, 9th, 10th samples are 011,101,110), the frame is discarded and the receiving sequence is not started for this frame. there is no rdrf bit set for this frame and the nf flag is set internally (not accessible to the user). this nf flag is accessible along with the rdrf bit when a next valid frame is received. note: if the application start bit is not long enough to match the above requirements, then the nf flag may get set due to the short start bit. in this case, the nf flag may be ignored by the applica- tion software when the first valid byte is received. see also section 10.5.4.10 . 1
st7232a 90/154 serial communications interface (cont?d) figure 52. sci baud rate and extended prescaler block diagram transmitter receiver scietpr scierpr extended prescaler receiver rate control extended prescaler transmitter rate control extended prescaler clock clock receiver rate transmitter rate scibrr scp1 f cpu control control scp0 sct2 sct1 sct0 scr2 scr1scr0 /pr /16 conventional baud rate generator extended receiver prescaler register extended transmitter prescaler register 1
st7232a 91/154 serial communications interface (cont?d) framing error a framing error is detected when: ? the stop bit is not recognized on reception at the expected time, following either a de-synchroni- zation or excessive noise. ? a break is received. when the framing error is detected: ? the fe bit is set by hardware ? data is transferred from the shift register to the scidr register. ? no interrupt is generated. however this bit rises at the same time as th e rdrf bit which itself generates an interrupt. the fe bit is reset by a scisr register read oper- ation followed by a scidr register read operation. 10.5.4.4 conventional baud rate generation the baud rate for the receiver and transmitter (rx and tx) are set independently and calculated as follows: with: pr = 1, 3, 4 or 13 (see scp[1:0] bits) tr = 1, 2, 4, 8, 16, 32, 64,128 (see sct[2:0] bits) rr = 1, 2, 4, 8, 16, 32, 64,128 (see scr[2:0] bits) all these bits are in the scibrr register. example: if f cpu is 8 mhz (normal mode) and if pr=13 and tr=rr=1, the transmit and receive baud rates are 38400 baud. note: the baud rate registers must not be changed while the transmitter or the receiver is en- abled. 10.5.4.5 extended baud rate generation the extended prescaler option gives a very fine tuning on the baud rate, using a 255 value prescal- er, whereas the conventional baud rate genera- tor retains industry stan dard software compatibili- ty. the extended baud rate generator block diagram is described in the figure 52 . the output clock rate sent to the transmitter or to the receiver will be the ou tput from the 16 divider divided by a factor ranging from 1 to 255 set in the scierpr or the scietpr register. note: the extended prescaler is activated by set- ting the scietpr or scierpr register to a value other than zero. the baud rates are calculated as follows: with: etpr = 1,..,255 (see scietpr register) erpr = 1,.. 255 (see scierpr register) 10.5.4.6 receiver muting and wake-up feature in multiprocessor configurat ions it is often desira- ble that only the intended message recipient should actively receive the full message contents, thus reducing redundant sci service overhead for all non addressed receivers. the non addressed devices may be placed in sleep mode by means of the muting function. setting the rwu bit by software puts the sci in sleep mode: all the reception status bits can not be set. all the receive interr upts are inhibited. a muted receiver may be awakened by one of the following two ways: ? by idle line detection if the wake bit is reset, ? by address mark detectio n if the wake bit is set. receiver wakes-up by idle line detection when the receive line has recognised an idle frame. then the rwu bit is reset by hardware but the idle bit is not set. receiver wakes-up by address mark detection when it received a ?1? as the most significant bit of a word, thus indicating that the message is an ad- dress. the reception of this particular word wakes up the receiver, resets the rwu bit and sets the rdrf bit, which allows the receiver to receive this word normally and to use it as an address word. caution : in mute mode, do not write to the scicr2 register. if the sci is in mute mode during the read operation (rwu=1) and a address mark wake up event occurs (rwu is reset) before the write operation, the rwu bit will be set again by this write operation. consequently the address byte is lost and the sci is not woken up from mute mode. tx = (16 * pr) * tr f cpu rx = (16 * pr) * rr f cpu tx = 16 * etpr*(pr*tr) f cpu rx = 16 * erpr*(pr*rr) f cpu 1
st7232a 92/154 serial communications interface (cont?d) 10.5.4.7 parity control parity control (generation of parity bit in transmis- sion and parity checking in reception) can be ena- bled by setting the pce bit in the scicr1 register. depending on the frame length defined by the m bit, the possible sci frame formats are as listed in table 20 . table 20. frame formats legend: sb = start bit, stb = stop bit, pb = parity bit note : in case of wake up by an address mark, the msb bit of the data is taken into account and not the parity bit even parity: the parity bit is calculated to obtain an even number of ?1s? inside the frame made of the 7 or 8 lsb bits (depending on whether m is equal to 0 or 1) and the parity bit. ex: data=00110101; 4 bits set => parity bit will be 0 if even parity is selected (ps bit = 0). odd parity: the parity bit is calculated to obtain an odd number of ?1s? inside the frame made of the 7 or 8 lsb bits (depending on whether m is equal to 0 or 1) and the parity bit. ex: data=00110101; 4 bits set => parity bit will be 1 if odd parity is selected (ps bit = 1). transmission mode: if the pce bit is set then the msb bit of the data written in the data register is not transmitted but is changed by the parity bit. reception mode: if the pce bit is set then the in- terface checks if the received data byte has an even number of ?1s? if even parity is selected (ps=0) or an odd number of ?1s? if odd parity is se- lected (ps=1). if the parity check fails, the pe flag is set in the scisr register and an interrupt is gen- erated if pie is set in the scicr1 register. 10.5.4.8 sci clock tolerance during reception, each bit is sampled 16 times. the majority of the 8th, 9th and 10th samples is considered as the bit value. for a valid bit detec- tion, all the three samples should have the same value otherwise the noise flag (nf) is set. for ex- ample: if the 8th, 9th and 10th samples are 0, 1 and 1 respectively, then the bit value will be ?1?, but the noise flag bit is be set because the three samples values are not the same. consequently, the bit length must be long enough so that the 8th, 9th and 10th samples have the de- sired bit value. this means the clock frequency should not vary more than 6/16 (37.5%) within one bit. the sampling clock is resynchronized at each start bit, so that when receiving 10 bits (one start bit, 1 data byte, 1 stop bit), the clock deviation must not exceed 3.75%. note: the internal sampling clock of the microcon- troller samples the pin value on every falling edge. therefore, the internal sampling clock and the time the application expects the sampling to take place may be out of sync. for example: if the baud rate is 15.625 kbaud (bit length is 64s), then the 8th, 9th and 10th samples will be at 28s, 32s & 36s respectively (the first sample starting ideally at 0s). but if the falling edge of the internal clock oc- curs just before the pin value changes, the sam- ples would then be out of sync by ~4us. this means the entire bit length must be at least 40s (36s for the 10th sample + 4s for synchroniza- tion with the internal sampling clock). m bit pce bit sci frame 0 0 | sb | 8 bit data | stb | 0 1 | sb | 7-bit data | pb | stb | 1 0 | sb | 9-bit data | stb | 1 1 | sb | 8-bit data pb | stb | 1
st7232a 93/154 serial communications interface (cont?d) 10.5.4.9 clock deviation causes the causes which contribute to the total deviation are: ?d tra : deviation due to transmitter error (local oscillator error of the tr ansmitter or the trans- mitter is transmitting at a different baud rate). ?d quant : error due to the baud rate quantisa- tion of the receiver. ?d rec : deviation of the lo cal oscillator of the receiver: this deviation can occur during the reception of one complete sci message as- suming that the deviation has been compen- sated at the beginning of the message. ?d tcl : deviation due to the transmission line (generally due to the transceivers) all the deviations of the system should be added and compared to the sci clock tolerance: d tra + d quant + d rec + d tcl < 3.75% 10.5.4.10 noise error causes see also description of noise error in section 10.5.4.3 . start bit the noise flag (nf) is set during start bit reception if one of the following conditions occurs: 1. a valid falling edge is not detected. a falling edge is considered to be valid if the 3 consecu- tive samples before t he falling edge occurs are detected as '1' and, after the falling edge occurs, during the sampling of the 16 samples, if one of the samples numbered 3, 5 or 7 is detected as a ?1?. 2. during sampling of the 16 samples, if one of the samples numbered 8, 9 or 10 is detected as a ?1?. therefore, a valid start bit must satisfy both the above conditions to prevent the noise flag getting set. data bits the noise flag (nf) is set during normal data bit re- ception if the following condition occurs: ? during the sampling of 16 samples, if all three samples numbered 8, 9 and10 are not the same. the majority of the 8th, 9th and 10th samples is considered as the bit value. therefore, a valid data bit must have samples 8, 9 and 10 at the same value to prevent the noise flag getting set. figure 53. bit sampling in reception mode rdi line sample clock 1234567891011 12 13 14 15 16 sampled values one bit time 6/16 7/16 7/16 1
st7232a 94/154 serial communications interface (cont?d) 10.5.5 low power modes 10.5.6 interrupts the sci interrupt events are connected to the same interrupt vector. these events generate an interrupt if the corre- sponding enable control bi t is set and the inter- rupt mask in the cc regist er is reset (rim instruc- tion). mode description wait no effect on sci. sci interrupts cause the device to exit from wait mode. halt sci registers are frozen. in halt mode, the sci stops transmit- ting/receiving until halt mode is exit- ed. interrupt event event flag enable control bit exit from wait exit from halt transmit data register empty tdre tie yes no transmission com- plete tc tcie yes no received data ready to be read rdrf rie yes no overrun error detected or yes no idle line detected idle ilie yes no parity error pe pie yes no 1
st7232a 95/154 serial communications interface (cont?d) 10.5.7 register description status register (scisr) read only reset value: 1100 0000 (c0h) bit 7 = tdre transmit data register empty. this bit is set by hardware when the content of the tdr register has been transferred into the shift register. an interrupt is generated if the tie bit=1 in the scicr2 register. it is cleared by a software sequence (an access to the scisr register fol- lowed by a write to the scidr register). 0: data is not transferred to the shift register 1: data is transferred to the shift register note: data will not be transfer red to the shift reg- ister unless the tdre bit is cleared. bit 6 = tc transmission complete. this bit is set by hardwar e when transmission of a frame containing data is complete. an interrupt is generated if tcie=1 in the scicr2 register. it is cleared by a software sequence (an access to the scisr register followed by a write to the scidr register). 0: transmission is not complete 1: transmission is complete note: tc is not set after the transmission of a pre- amble or a break. bit 5 = rdrf received data ready flag. this bit is set by hardware when the content of the rdr register has been transferred to the scidr register. an interrupt is generated if rie=1 in the scicr2 register. it is cleared by a software se- quence (an access to the scisr register followed by a read to the scidr register). 0: data is not received 1: received data is ready to be read bit 4 = idle idle line detect. this bit is set by hardware when a idle line is de- tected. an interrupt is generated if the ilie=1 in the scicr2 register. it is cleared by a software se- quence (an access to the scisr register followed by a read to the scidr register). 0: no idle line is detected 1: idle line is detected note: the idle bit will not be set again until the rdrf bit has been set itself (i.e. a new idle line oc- curs). bit 3 = or overrun error. this bit is set by hardware when the word currently being received in the shift register is ready to be transferred into the rdr register while rdrf=1. an interrupt is generated if rie=1 in the scicr2 register. it is cleared by a software sequence (an access to the scisr register followed by a read to the scidr register). 0: no overrun error 1: overrun error is detected note: when this bit is set rdr register content will not be lost but the shift re gister will be overwritten. bit 2 = nf noise flag. this bit is set by hardware when noise is detected on a received frame. it is cleared by a software se- quence (an access to the scisr register followed by a read to the scidr register). 0: no noise is detected 1: noise is detected note: this bit does not generate interrupt as it ap- pears at the same time as the rdrf bit which it- self generates an interrupt. bit 1 = fe framing error. this bit is set by hardware when a de-synchroniza- tion, excessive noise or a break character is de- tected. it is cleared by a software sequence (an access to the scisr register followed by a read to the scidr register). 0: no framing error is detected 1: framing error or break character is detected note: this bit does not generate interrupt as it ap- pears at the same time as the rdrf bit which it- self generates an interrupt. if the word currently being transferred causes both frame error and overrun error, it will be tr ansferred and only the or bit will be set. bit 0 = pe parity error. this bit is set by hardware when a parity error oc- curs in receiver mode. it is cleared by a software sequence (a read to the status register followed by an access to the scidr data register). an inter- rupt is generated if pie=1 in the scicr1 register. 0: no parity error 1: parity error 70 tdre tc rdrf idle or nf fe pe 1
st7232a 96/154 serial communications interface (cont?d) control register 1 (scicr1) read/write reset value: x000 0000 (x0h) bit 7 = r8 receive data bit 8. this bit is used to store the 9th bit of the received word when m=1. bit 6 = t8 transmit data bit 8. this bit is used to store the 9th bit of the transmit- ted word when m=1. bit 5 = scid disabled for low power consumption when this bit is set the sci prescalers and outputs are stopped and the end of the current byte trans- fer in order to reduce power consumption.this bit is set and cleared by software. 0: sci enabled 1: sci prescaler and outputs disabled bit 4 = m word length. this bit determines the word length. it is set or cleared by software. 0: 1 start bit, 8 data bits, 1 stop bit 1: 1 start bit, 9 data bits, 1 stop bit note : the m bit must not be modified during a data transfer (both transmission and reception). bit 3 = wake wake-up method. this bit determines the sci wake-up method, it is set or cleared by software. 0: idle line 1: address mark bit 2 = pce parity control enable. this bit selects the hardware parity control (gener- ation and detection). when the parity control is en- abled, the computed parity is inserted at the msb position (9th bit if m=1; 8th bit if m=0) and parity is checked on the received data. this bit is set and cleared by software. once it is set, pce is active after the current byte (in reception and in transmis- sion). 0: parity control disabled 1: parity control enabled bit 1 = ps parity selection. this bit selects the odd or even parity when the parity generation/detection is enabled (pce bit set). it is set and cleared by software. the parity will be selected afte r the current byte. 0: even parity 1: odd parity bit 0 = pie parity interrupt enable. this bit enables the interrupt capability of the hard- ware parity control when a parity error is detected (pe bit set). it is set and cleared by software. 0: parity error interrupt disabled 1: parity error interrupt enabled. 70 r8 t8 scid m wake pce ps pie 1
st7232a 97/154 serial communications interface (cont?d) control register 2 (scicr2) read/write reset value: 0000 0000 (00h) bit 7 = tie transmitter interrupt enable . this bit is set and cleared by software. 0: interrupt is inhibited 1: an sci interrupt is generated whenever tdre=1 in the scisr register bit 6 = tcie transmission complete interrupt ena- ble this bit is set and cleared by software. 0: interrupt is inhibited 1: an sci interrupt is generated whenever tc=1 in the scisr register bit 5 = rie receiver interrupt enable . this bit is set and cleared by software. 0: interrupt is inhibited 1: an sci interrupt is generated whenever or=1 or rdrf=1 in the scisr register bit 4 = ilie idle line interrupt enable. this bit is set and cleared by software. 0: interrupt is inhibited 1: an sci interrupt is generated whenever idle=1 in the scisr register. bit 3 = te transmitter enable. this bit enables the transmitter. it is set and cleared by software. 0: transmitter is disabled 1: transmitter is enabled notes: ? during transmission, a ?0? pulse on the te bit (?0? followed by ?1?) sends a preamble (idle line) after the current word. ? when te is set there is a 1 bit-time delay before the transmission starts. caution: the tdo pin is free for general purpose i/o only when the te and re bits are both cleared (or if te is never set). bit 2 = re receiver enable. this bit enables the receiver. it is set and cleared by software. 0: receiver is disabled 1: receiver is enabled and begins searching for a start bit bit 1 = rwu receiver wake-up. this bit determines if the sci is in mute mode or not. it is set and cleared by software and can be cleared by hardware when a wake-up sequence is recognized. 0: receiver in active mode 1: receiver in mute mode note: before selecting mute mode (setting the rwu bit), the sci must receive some data first, otherwise it cannot function in mute mode with wakeup by idle line detection. bit 0 = sbk send break. this bit set is used to send break characters. it is set and cleared by software. 0: no break character is transmitted 1: break characters are transmitted note: if the sbk bit is set to ?1? and then to ?0?, the transmitter will send a break word at the end of the current word. 70 tie tcie rie ilie te re rwu sbk 1
st7232a 98/154 serial communications interface (cont?d) data register (scidr) read/write reset value: undefined contains the received or transmitted data char- acter, depending on whether it is read from or writ- ten to. the data register performs a double function (read and write) since it is composed of two registers, one for transmission (tdr) and one for reception (rdr). the tdr register provides the parallel interface between the internal bus and the output shift reg- ister (see figure 50 ). the rdr register provides the parallel interface between the input shift register and the internal bus (see figure 50 ). baud rate register (scibrr) read/write reset value: 0000 0000 (00h) bits 7:6= scp[1:0] first sci prescaler these 2 prescaling bits allow several standard clock division ranges: bits 5:3 = sct[2:0] sci transmitter rate divisor these 3 bits, in conjunction with the scp1 & scp0 bits define the total division applied to the bus clock to yield the transmit rate clock in convention- al baud rate generator mode. bits 2:0 = scr[2:0] sci receiver rate divisor. these 3 bits, in conjunction with the scp[1:0] bits define the total division applied to the bus clock to yield the receive rate cl ock in conventional baud rate generator mode. 70 dr7 dr6 dr5 dr4 dr3 dr2 dr1 dr0 70 scp1 scp0 sct2 sct1 sct0 scr2 scr1 scr0 pr prescaling factor scp1 scp0 100 301 410 13 1 1 tr dividing factor sct2 sct1 sct0 1000 2001 4010 8011 16 1 0 0 32 1 0 1 64 1 1 0 128 1 1 1 rr dividing factor scr2 scr1 scr0 1000 2001 4010 8011 16 1 0 0 32 1 0 1 64 1 1 0 128 1 1 1 1
st7232a 99/154 serial communications interface (cont?d) extended receive prescaler division register (scierpr) read/write reset value: 0000 0000 (00h) allows setting of the extended prescaler rate divi- sion factor for the receive circuit. bits 7:0 = erpr[7:0] 8-bit extended receive prescaler register. the extended baud rate generator is activated when a value different from 00h is stored in this register. therefore the clock frequency issued from the 16 divider (see figure 52 ) is divided by the binary factor set in the scierpr register (in the range 1 to 255). the extended baud rate generator is not used af- ter a reset. extended transmit prescaler division register (scietpr) read/write reset value:0000 0000 (00h) allows setting of the external prescaler rate divi- sion factor for the transmit circuit. bits 7:0 = etpr[7:0] 8-bit extended transmit prescaler register. the extended baud rate generator is activated when a value different from 00h is stored in this register. therefore the clock frequency issued from the 16 divider (see figure 52 ) is divided by the binary factor set in the scietpr register (in the range 1 to 255). the extended baud rate generator is not used af- ter a reset. table 21. baudrate selection 70 erpr 7 erpr 6 erpr 5 erpr 4 erpr 3 erpr 2 erpr 1 erpr 0 70 etpr 7 etpr 6 etpr 5 etpr 4 etpr 3 etpr 2 etpr 1 etpr 0 symbol parameter conditions standard baud rate unit f cpu accuracy vs. standard prescaler f tx f rx communication frequency 8mhz ~0.16% conventional mode tr (or rr)=128, pr=13 tr (or rr)= 32, pr=13 tr (or rr)= 16, pr=13 tr (or rr)= 8, pr=13 tr (or rr)= 4, pr=13 tr (or rr)= 16, pr= 3 tr (or rr)= 2, pr=13 tr (or rr)= 1, pr=13 300 1200 2400 4800 9600 10400 19200 38400 ~300.48 ~1201.92 ~2403.84 ~4807.69 ~9615.38 ~10416.67 ~19230.77 ~38461.54 hz ~0.79% extended mode etpr (or erpr) = 35, tr (or rr)= 1, pr=1 14400 ~14285.71 1
st7232a 100/154 serial communication interface (cont?d) table 22. sci register map and reset values address (hex.) register label 76543210 0050h scisr reset value tdre 1 tc 1 rdrf 0 idle 0 or 0 nf 0 fe 0 pe 0 0051h scidr reset value msb xxxxxxx lsb x 0052h scibrr reset value scp1 0 scp0 0 sct2 0 sct1 0 sct0 0 scr2 0 scr1 0 scr0 0 0053h scicr1 reset value r8 x t8 0 scid 0 m 0 wake 0 pce 0 ps 0 pie 0 0054h scicr2 reset value tie 0 tcie 0 rie 0 ilie 0 te 0 re 0 rwu 0 sbk 0 0055h scierpr reset value msb 0000000 lsb 0 0057h scipetpr reset value msb 0000000 lsb 0 1
st7232a 101/154 10.6 10-bit a/d converter (adc) 10.6.1 introduction the on-chip analog to digital converter (adc) pe- ripheral is a 10-bit, successive approximation con- verter with internal sample and hold circuitry. this peripheral has up to 16 multiplexed analog input channels (refer to device pin out description) that allow the peripheral to convert the analog voltage levels from up to 16 different sources. the result of the conversion is stored in a 10-bit data register. the a/d converter is controlled through a control/status register. 10.6.2 main features 10-bit conversion up to 16 channels with multiplexed input linear successive approximation data register (dr) which contains the results conversion complete status flag on/off bit (to reduce consumption) the block diagram is shown in figure 54 . figure 54. adc block diagram ch2 ch1 eoc speed adon 0 ch0 adccsr ain0 ain1 analog to digital converter ainx analog mux d4 d3 d5 d9 d8 d7 d6 d2 adcdrh 4 div 4 f adc f cpu d1 d0 adcdrl 0 1 00 0000 ch3 div 2 1
st7232a 102/154 10-bit a/d converter (adc) (cont?d) 10.6.3 functional description the conversion is monotonic, meaning that the re- sult never decreases if the analog input does not and never increases if the analog input does not. if the input voltage (v ain ) is greater than v aref (high-level voltage reference) then the conversion result is ffh in the a dcdrh register and 03h in the adcdrl register (with out overflow indication). if the input voltage (v ain ) is lower than v ssa (low- level voltage reference) then the conversion result in the adcdrh and adcdrl registers is 00 00h. the a/d converter is linear and the digital result of the conversion is stored in the adcdrh and ad- cdrl registers. the accuracy of the conversion is described in the electrical characteristics section. r ain is the maximum recommended impedance for an analog input signal. if the impedance is too high, this will result in a loss of accuracy due to leakage and sampling not being completed in the alloted time. 10.6.3.1 a/d converter configuration the analog input ports must be configured as in- put, no pull-up, no interrupt. refer to the ?i/o ports? chapter. using these pins as analog inputs does not affect the ability of the port to be read as a logic input. in the adccsr register: ? select the cs[3:0] bits to assign the analog channel to convert. 10.6.3.2 starting the conversion in the adccsr register: ? set the adon bit to enable the a/d converter and to start the conversion. from this time on, the adc performs a continuous conversion of the selected channel. when a conversion is complete: ? the eoc bit is set by hardware. ? the result is in the adcdr registers. a read to the adcdrh resets the eoc bit. to read the 10 bits, perform the following steps: 1. poll the eoc bit 2. read the adcdrl register 3. read the adcdrh register. this clears eoc automatically. note: the data is not latched, so both the low and the high data register must be read before the next conversion is complete, so it is recommended to disable interrupts while reading the conversion re- sult. to read only 8 bits, perform the following steps: 1. poll the eoc bit 2. read the adcdrh register. this clears eoc automatically. 10.6.3.3 changing the conversion channel the application can change channels during con- version. when software modifies the ch[3:0] bits in the adccsr register, the current conversion is stopped, the eoc bit is cleared, and the a/d con- verter starts converting the newly selected chan- nel. 10.6.4 low power modes note: the a/d converter may be disabled by re- setting the adon bit. this feature allows reduced power consumption when no conversion is need- ed. 10.6.5 interrupts none. mode description wait no effect on a/d converter halt a/d converter disabled. after wakeup from halt mode, the a/d converter requires a stabilization time t stab (see electrical characteristics) before accurate conversions can be performed. 1
st7232a 103/154 10-bit a/d converter (adc) (cont?d) 10.6.6 register description control/status register (adccsr) read/write (except bit 7 read only) reset value: 0000 0000 (00h) bit 7 = eoc end of conversion this bit is set by hardware. it is cleared by hard- ware when software reads the adcdrh register or writes to any bit of the adccsr register. 0: conversion is not complete 1: conversion complete bit 6 = speed adc clock selection this bit is set and cleared by software. 0: f adc = f cpu /4 1: f adc = f cpu /2 bit 5 = adon a/d converter on this bit is set and cleared by software. 0: disable adc and stop conversion 1: enable adc and start conversion bit 4 = reserved. must be kept cleared. bit 3:0 = ch[3:0] channel selection these bits are set and cleared by software. they select the analog input to convert. *the number of channels is device dependent. refer to the device pinout description. data register (adcdrh) read only reset value: 0000 0000 (00h) bit 7:0 = d[9:2] msb of converted analog value data register (adcdrl) read only reset value: 0000 0000 (00h) bit 7:2 = reserved. forced by hardware to 0. bit 1:0 = d[1:0] lsb of converted analog value 70 eoc speed adon 0 ch3 ch2 ch1 ch0 channel pin* ch3 ch2 ch1 ch0 ain0 0 0 0 0 ain1 0 0 0 1 ain2 0 0 1 0 ain3 0 0 1 1 ain4 0 1 0 0 ain5 0 1 0 1 ain6 0 1 1 0 ain7 0 1 1 1 ain8 1 0 0 0 ain9 1 0 0 1 ain10 1 0 1 0 ain11 1 0 1 1 ain12 1 1 0 0 ain13 1 1 0 1 ain14 1 1 1 0 ain15 1 1 1 1 70 d9 d8 d7 d6 d5 d4 d3 d2 70 000000d1d0 1
st7232a 104/154 10-bit a/d converter (cont?d) table 23. adc register map and reset values address (hex.) register label 76543210 0070h adccsr reset value eoc 0 speed 0 adon 00 ch3 0 ch2 0 ch1 0 ch0 0 0071h adcdrh reset value d9 0 d8 0 d7 0 d6 0 d5 0 d4 0 d3 0 d2 0 0072h adcdrl reset value000000 d1 0 d0 0 1
st7232a 105/154 11 instruction set 11.1 cpu addressing modes the cpu features 17 different addressing modes which can be classified in 7 main groups: the cpu instruction set is designed to minimize the number of bytes required per instruction: to do so, most of the addressing modes may be subdi- vided in two sub-modes called long and short: ? long addressing mode is more powerful be- cause it can use the full 64 kbyte address space, however it uses more bytes and more cpu cy- cles. ? short addressing mode is less powerful because it can generally only access page zero (0000h - 00ffh range), but the instruction size is more compact, and faster. all memory to memory in- structions use short addressing modes only (clr, cpl, neg, bset, bres, btjt, btjf, inc, dec, rlc, rrc, sll, srl, sra, swap) the st7 assembler optimizes the use of long and short addressing modes. table 24. cpu addressing mode overview addressing mode example inherent nop immediate ld a,#$55 direct ld a,$55 indexed ld a,($55,x) indirect ld a,([$55],x) relative jrne loop bit operation bset byte,#5 mode syntax destination pointer address (hex.) pointer size (hex.) length (bytes) inherent nop + 0 immediate ld a,#$55 + 1 short direct ld a,$10 00..ff + 1 long direct ld a,$1000 0000..ffff + 2 no offset direct indexed ld a,(x) 00..ff + 0 short direct indexed ld a,($10,x) 00..1fe + 1 long direct indexed ld a,($1000,x) 0000..ffff + 2 short indirect ld a,[$10] 00..ff 00..ff byte + 2 long indirect ld a,[$10.w] 0000..ffff 00..ff word + 2 short indirect indexed ld a,([ $10],x) 00..1fe 00..ff byte + 2 long indirect indexed ld a,([$10. w],x) 0000..ffff 00..ff word + 2 relative direct jrne loop pc+/-127 + 1 relative indirect jrne [$10] pc+/-127 00..ff byte + 2 bit direct bset $10,#7 00..ff + 1 bit indirect bset [$10],# 7 00..ff 00..ff byte + 2 bit direct relative btjt $10,#7,skip 00..ff + 2 bit indirect relative btjt [$10] ,#7,skip 00..ff 00..ff byte + 3 1
st7232a 106/154 instruction set overview (cont?d) 11.1.1 inherent all inherent instructions consist of a single byte. the opcode fully specifies all the required informa- tion for the cpu to process the operation. 11.1.2 immediate immediate instructions have two bytes, the first byte contains the opcode, the second byte con- tains the operand value. 11.1.3 direct in direct instructions, the operands are referenced by their memory address. the direct addressing mode consists of two sub- modes: direct (short) the address is a byte, t hus requires only one byte after the opcode, but only allows 00 - ff address- ing space. direct (long) the address is a word, thus allowing 64 kbyte ad- dressing space, but requires 2 bytes after the op- code. 11.1.4 indexed (no offset, short, long) in this mode, the operand is referenced by its memory address, which is defined by the unsigned addition of an index register (x or y) with an offset. the indirect addressing mode consists of three sub-modes: indexed (no offset) there is no offset, (no extra byte after the opcode), and allows 00 - ff addressing space. indexed (short) the offset is a byte, thus requires only one byte af- ter the opcode and allows 00 - 1fe addressing space. indexed (long) the offset is a word, thus allowing 64 kbyte ad- dressing space and requires 2 bytes after the op- code. 11.1.5 indirect (short, long) the required data byte to do the operation is found by its memory address, located in memory (point- er). the pointer address follows the opcode. the indi- rect addressing mode consists of two sub-modes: indirect (short) the pointer address is a byte, the pointer size is a byte, thus allowing 00 - ff addressing space, and requires 1 byte after the opcode. indirect (long) the pointer address is a byte, the pointer size is a word, thus allowing 64 kbyte addressing space, and requires 1 byte after the opcode. inherent instruction function nop no operation trap s/w interrupt wfi wait for interrupt (low pow- er mode) halt halt oscillator (lowest power mode) ret sub-routine return iret interrupt sub-routine return sim set interrupt mask (level 3) rim reset interrupt mask (level 0) scf set carry flag rcf reset carry flag rsp reset stack pointer ld load clr clear push/pop push/pop to/from the stack inc/dec increment/decrement tnz test negative or zero cpl, neg 1 or 2 complement mul byte multiplication sll, srl, sra, rlc, rrc shift and rotate operations swap swap nibbles immediate instruction function ld load cp compare bcp bit compare and, or, xor logical operations adc, add, sub, sbc arithmetic operations 1
st7232a 107/154 instruction set overview (cont?d) 11.1.6 indirect indexed (short, long) this is a combination of indirect and short indexed addressing modes. the operand is referenced by its memory address, which is defined by the un- signed addition of an index register value (x or y) with a pointer value located in memory. the point- er address follows the opcode. the indirect indexed addressing mode consists of two sub-modes: indirect indexed (short) the pointer address is a byte, the pointer size is a byte, thus allowing 00 - 1fe addressing space, and requires 1 byte after the opcode. indirect indexed (long) the pointer address is a byte, the pointer size is a word, thus allowing 64 kbyte addressing space, and requires 1 byte after the opcode. table 25. instructions supporting direct, indexed, indirect and indirect indexed addressing modes 11.1.7 relative mode (direct, indirect) this addressing mode is used to modify the pc register value, by adding an 8-bit signed offset to it. the relative addressing mode consists of two sub- modes: relative (direct) the offset is following the opcode. relative (indirect) the offset is defined in memory, which address follows the opcode. long and short instructions function ld load cp compare and, or, xor logical operations adc, add, sub, sbc arithmetic additions/sub- stractions operations bcp bit compare short instructions only function clr clear inc, dec increment/decrement tnz test negative or zero cpl, neg 1 or 2 complement bset, bres bit operations btjt, btjf bit test and jump opera- tions sll, srl, sra, rlc, rrc shift and rotate opera- tions swap swap nibbles call, jp call or jump subroutine available relative direct/indirect instructions function jrxx conditional jump callr call relative 1
st7232a 108/154 instruction set overview (cont?d) 11.2 instruction groups the st7 family devices use an instruction set consisting of 63 instructions. the instructions may be subdivided into 13 ma in groups as illustrated in the following table: using a pre-byte the instructions are described with one to four op- codes. in order to extend the number of available op- codes for an 8-bit cpu (256 opcodes), three differ- ent prebyte opcodes are defined. these prebytes modify the meaning of the instruction they pre- cede. the whole instruction becomes: pc-2 end of previous instruction pc-1 prebyte pc opcode pc+1 additional word (0 to 2) according to the number of bytes required to compute the ef- fective address these prebytes enable instruction in y as well as indirect addressing modes to be implemented. they precede the opcode of the instruction in x or the instruction using direct addressing mode. the prebytes are: pdy 90 replace an x based instruction using immediate, direct, indexed, or inherent ad- dressing mode by a y one. pix 92 replace an instruction using di- rect, direct bit, or direct relative addressing mode to an instruction using the corresponding indirect addressing mode. it also changes an instruction using x indexed ad- dressing mode to an instruction using indirect x in- dexed addressing mode. piy 91 replace an instruction using x in- direct indexed addressing mode by a y one. load and transfer ld clr stack operation push pop rsp increment/decrement inc dec compare and tests cp tnz bcp logical operations and or xor cpl neg bit operation bset bres conditional bit test and branch btjt btjf arithmetic operations adc add sub sbc mul shift and rotates sll srl sra rlc rrc swap sla unconditional jump or call jra jrt jrf jp call callr nop ret conditional branch jrxx interruption management trap wfi halt iret condition code flag modification sim rim scf rcf 1
st7232a 109/154 instruction set overview (cont?d) mnemo description function/example dst src i1 h i0 n z c adc add with carry a = a + m + c a m h n z c add addition a = a + m a m h n z c and logical and a = a . m a m n z bcp bit compare a, memory tst (a . m) a m n z bres bit reset bres byte, #3 m bset bit set bset byte, #3 m btjf jump if bit is false (0) btjf byte, #3, jmp1 m c btjt jump if bit is true (1) btjt byte, #3, jmp1 m c call call subroutine callr call subroutine relative clr clear reg, m 0 1 cp arithmetic compare tst(reg - m) reg m n z c cpl one complement a = ffh-a reg, m n z 1 dec decrement dec y reg, m n z halt halt 1 0 iret interrupt routine return pop cc, a, x, pc i1 h i0 n z c inc increment inc x reg, m n z jp absolute jump jp [tbl.w] jra jump relative always jrt jump relative jrf never jump jrf * jrih jump if ext. int pin = 1 (ext. int pin high) jril jump if ext. int pin = 0 (ext. int pin low) jrh jump if h = 1 h = 1 ? jrnh jump if h = 0 h = 0 ? jrm jump if i1:0 = 11 i1:0 = 11 ? jrnm jump if i1:0 <> 11 i1:0 <> 11 ? jrmi jump if n = 1 (minus) n = 1 ? jrpl jump if n = 0 (plus) n = 0 ? jreq jump if z = 1 (equal) z = 1 ? jrne jump if z = 0 (not equal) z = 0 ? jrc jump if c = 1 c = 1 ? jrnc jump if c = 0 c = 0 ? jrult jump if c = 1 unsigned < jruge jump if c = 0 jmp if unsigned >= jrugt jump if (c + z = 0) unsigned > 1
st7232a 110/154 instruction set overview (cont?d) mnemo description function/example dst src i1 h i0 n z c jrule jump if (c + z = 1) unsigned <= ld load dst <= src reg, m m, reg n z mul multiply x,a = x * a a, x, y x, y, a 0 0 neg negate (2's compl) neg $10 reg, m n z c nop no operation or or operation a = a + m a m n z pop pop from the stack pop reg reg m pop cc cc m i1 h i0 n z c push push onto the stack push y m reg, cc rcf reset carry flag c = 0 0 ret subroutine return rim enable interrupts i1:0 = 10 (level 0) 1 0 rlc rotate left true c c <= a <= c reg, m n z c rrc rotate right true c c => a => c reg, m n z c rsp reset stack pointer s = max allowed sbc substract with carry a = a - m - c a m n z c scf set carry flag c = 1 1 sim disable interrupts i1:0 = 11 (level 3) 1 1 sla shift left arithmetic c <= a <= 0 reg, m n z c sll shift left logic c <= a <= 0 reg, m n z c srl shift right logic 0 => a => c reg, m 0 z c sra shift right arithmetic a7 => a => c reg, m n z c sub substraction a = a - m a m n z c swap swap nibbles a7-a4 <=> a3-a0 reg, m n z tnz test for neg & zero tnz lbl1 n z trap s/w trap s/w interrupt 1 1 wfi wait for interrupt 1 0 xor exclusive or a = a xor m a m n z 1
st7232a 111/154 12 electrical characteristics 12.1 parameter conditions unless otherwise specified, all voltages are re- ferred to v ss . 12.1.1 minimum and maximum values unless otherwise specified the minimum and max- imum values are guaranteed in the worst condi- tions of ambient temperature, supply voltage and frequencies by tests in production on 100% of the devices with an ambient temperature at t a =25c and t a =t a max (given by the selected temperature range). data based on characterization results, design simulation and/or technology characteristics are indicated in the table footnotes and are not tested in production. based on characterization, the min- imum and maximum values refer to sample tests and represent the mean value plus or minus three times the standard deviation (mean3 ). 12.1.2 typical values unless otherwise specified, typical data are based on t a =25c, v dd =5v. they are given only as de- sign guidelines and are not tested. 12.1.3 typical curves unless otherwise specified, all typical curves are given only as design guidelines and are not tested. 12.1.4 loading capacitor the loading conditions used for pin parameter measurement are shown in figure 55 . figure 55. pin loading conditions 12.1.5 pin input voltage the input voltage measurement on a pin of the de- vice is described in figure 56 . figure 56. pin input voltage c l st7 pin v in st7 pin 1
st7232a 112/154 12.2 absolute ma ximum ratings stresses above those listed as ?absolute maxi- mum ratings? may cause permanent damage to the device. this is a stress rating only and func- tional operation of the device under these condi- tions is not implied. exposure to maximum rating conditions for extended periods may affect device reliability. 12.2.1 voltage characteristics 12.2.2 current characteristics notes: 1. directly connecting the reset and i/o pins to v dd or v ss could damage the device if an uni ntentional internal reset is generated or an unexpected change of the i/o configuration occurs (for exampl e, due to a corrupt ed program counter). to guarantee safe operation, this connection has to be done through a pull-up or pull-down resistor (typical: 4.7k ? for reset , 10k ? for i/os). for the same reason, unused i/ o pins must not be directly tied to v dd or v ss . 2. i inj(pin) must never be exceeded. this is implicitly insured if v in maximum is respected. if v in maximum cannot be respected, the injection current mu st be limited externally to the i inj(pin) value. a positive injection is induced by v in >v dd while a negative injection is induced by v in st7232a 113/154 12.2.3 thermal characteristics 12.3 operating conditions 12.3.1 operating conditions figure 57. f cpu max versus v dd note: some temperature ranges are only available with a specific package and memory size. refer to or- dering information. warning : do not connect 12v to v pp before v dd is powered on, as this may damage the device. symbol ratings value unit t stg storage temperature range -65 to +150 c t j maximum junction temperature (see section 13.2 thermal characteristics ) symbol parameter conditions min max unit f cpu internal clock frequency 0 8 mhz v dd operating voltage (except flash write/ erase) 3.8 5.5 v operating voltage for flash write/erase v pp = 11.4 to 12.6v 4.5 5.5 t a ambient temperature range 1 suffix version 0 70 c 5 suffix version -10 85 6 or a suffix versions -40 85 f cpu [mhz] supply voltage [v] 8 4 2 1 0 3.5 4.0 4.5 5.5 functionality functionality guaranteed in this area not guaranteed in this area 3.8 6 (unless otherwise specified in the tables of parametric data) 1
st7232a 114/154 12.4 supply current characteristics the following current consumption specified for the st7 functional operating modes over temperature range does not take into account the clock source current consumption. to get the total device consump- tion, the two current values must be added (except for halt mode for which the clock is stopped). 12.4.1 current consumption notes: 1. data based on characterization results, tested in production at v dd max. and f cpu max. 2. measurements are done in the following conditions: - progam executed from ram, cpu running with ram access. the increase in consumption when executing from flash is 50%. - all i/o pins in input mode with a static value at v dd or v ss (no load) - all peripherals in reset state. - clock input (osc1) driven by external square wave. - in slow and slow wait mode, f cpu is based on f osc divided by 32. to obtain the total current consumption of the device, add the clock source ( section 12.5.3 ) and the peripheral power consumption ( section 12.4.3 ). 3. all i/o pins in push-pull 0 mode (w hen applicable) with a static value at v dd or v ss (no load). data based on charac- terization results, tested in production at v dd max. and f cpu max. 4. data based on characterisation results , not tested in production. all i/o pins in push-pull 0 mode (when applicable) with a static value at v dd or v ss (no load); clock input (osc1) driven by exte rnal square wave. to obtain the total current consumption of the device, add t he clock source consumption ( section 12.5.3 ). symbol parameter conditions flash devices rom devices unit typ max 1) typ max 1) i dd supply current in run mode 2) f osc =2mhz, f cpu =1mhz f osc =4mhz, f cpu =2mhz f osc =8mhz, f cpu =4mhz f osc =16mhz, f cpu =8mhz 1 1.4 2.4 4.4 2.3 3.5 5.3 7.0 1.3 2.0 3.6 7.1 2.0 3.0 5 10 ma supply current in slow mode 2) f osc =2mhz, f cpu =62.5khz f osc =4mhz, f cpu =125khz f osc =8mhz, f cpu =250khz f osc =16mhz, f cpu =500khz 0.48 0.53 0.63 0.80 1 1.1 1.2 1.4 0.6 0.7 0.8 1.1 1.8 2.1 2.4 3.0 ma supply current in wait mode 2) f osc =2mhz, f cpu =1mhz f osc =4mhz, f cpu =2mhz f osc =8mhz, f cpu =4mhz f osc =16mhz, f cpu =8mhz 0.6 0.9 1.3 2.3 1.8 2.2 2.6 3.6 1 1.5 2.5 4.5 1.3 2.0 3.3 6 ma supply current in slow wait mode 2) f osc =2mhz, f cpu =62.5khz f osc =4mhz, f cpu =125khz f osc =8mhz, f cpu =250khz f osc =16mhz, f cpu =500khz 430 470 530 660 950 1000 1050 1200 70 100 200 350 200 300 600 1200 a supply current in halt mode 3) -40c t a +85c <1 10 <1 10 a supply current in active-halt mode 4) f osc =2mhz f osc =4mhz f osc =8mhz f osc =16mhz 60 100 180 340 160 200 300 500 22 44 86 170 30 60 120 300 a 1
st7232a 115/154 supply current characteristics (cont?d) 12.4.1.1 power consumption vs f cpu : flash devices figure 58. typical i dd in run mode figure 59. typical i dd in slow mode figure 60. typical i dd in wait mode figure 61. typ. i dd in slow-wait mode 0 1 2 3 4 5 6 3 3.3 3.6 3.9 4.2 4 .5 4.8 5. 1 5.4 5.7 6 vdd (v) idd (ma) 2mhz 4mhz 8mhz 16mhz 0 0.2 0.4 0.6 0.8 1 1.2 3 3.3 3 .6 3 . 9 4 .2 4 .5 4 . 8 5 .1 5 . 4 5 . 7 6 vdd (v) idd (ma) 2mhz 4mhz 8mhz 16mhz 0 0.5 1 1.5 2 2.5 3 3.5 3 3.3 3. 6 3.9 4. 2 4.5 4. 8 5.1 5. 4 5.7 6 vdd (v) idd (ma) 2mhz 4mhz 8mhz 16mhz 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 3 3 . 3 3.6 3.9 4 . 2 4 . 5 4 .8 5.1 5 . 4 5 . 7 6 vdd (v) idd (ma) 2mhz 4mhz 8mhz 16mhz 1
st7232a 116/154 supply current characteristics (cont?d) 12.4.2 supply and clock managers the previous current consumption specified for t he st7 functional operating modes over temperature range does not take into account the clock source current consumption. to get the total device consump- tion, the two current values must be added (except for halt mode). notes: 1. data based on characterization results done wi th the external components specified in section 12.5.3 , not tested in production. 2. as the oscillator is based on a current sour ce, the consumption does not depend on the voltage. symbol parameter conditions typ max unit i dd(res) supply current of re sonator oscillator 1) & 2) see section 12.5.3 on page 119 a i dd(pll) pll supply current v dd = 5v 360 a 1
st7232a 117/154 supply current characteristics (cont?d) 12.4.3 on-chip peripherals t a = 25c f cpu =4mhz. notes: 1. data based on a differential i dd measurement between reset configur ation (timer count er running at f cpu /4) and timer counter stopped (only ti md bit set). data valid for one timer. 2. data based on a differential i dd measurement between reset configuration (spi disabled) and a permanent spi master communication at maximum speed (data sent equal to 55h) . this measurement includes the pad toggling consump- tion. 3. data based on a differential i dd measurement between sci low power state (scid=1) and a permanent sci data trans- mit sequence. 4. data based on a differential i dd measurement between reset configur ation and continuous a/d conversions. symbol parameter conditions typ unit i dd(tim) 16-bit timer supply current 1) v dd = 5.0v 50 a i dd(spi) spi supply current 2) v dd = 5.0v 400 i dd(sci) sci supply current 3) v dd = 5.0v 400 i dd(adc) adc supply current when converting 4) v dd = 5.0v 400 1
st7232a 118/154 12.5 clock and timing characteristics subject to general operating conditions for v dd , f cpu , and t a . 12.5.1 general timings 12.5.2 external clock source figure 62. typical application with an external clock source notes: 1. data based on typical application software. 2. time measured between interrupt event and interrupt vector fetch. ? t c(inst) is the number of t cpu cycles needed to finish the current instru ction execution. 3. data based on design simulation and/or technol ogy characteristics, not tested in production. symbol parameter conditions min typ 1) max unit t c(inst) instruction cycle time 2312t cpu f cpu =8mhz 250 375 1500 ns t v(it) interrupt reaction time 2) t v(it) = ? t c(inst) + 10 10 22 t cpu f cpu =8mhz 1.25 2.75 s symbol parameter conditions min typ max unit v osc1h osc1 input pin high level voltage see figure 62 v dd -1 v dd v v osc1l osc1 input pin low level voltage v ss v ss +1 t w(osc1h) t w(osc1l) osc1 high or low time 3) 5 ns t r(osc1) t f(osc1) osc1 rise or fall time 3) 15 i l osc1 input leakage current v ss v in v dd 1 a osc1 osc2 f osc external st72xxx clock source not connected internally v osc1l v osc1h t r(osc1) t f(osc1) t w(osc1h) t w(osc1l) i l 90% 10% 1
st7232a 119/154 clock and timing characteristics (cont?d) 12.5.3 crystal and ceramic resonator oscillators the st7 internal clock can be supplied with four different crystal/ceramic resonator oscillators. all the information given in this paragraph are based on characterization results with specified typical external components. in the application, the reso- nator and the load capacitors have to be placed as close as possible to the oscillator pins in order to minimize output distorti on and start-up stabiliza- tion time. refer to the crystal/ceramic resonator manufacturer for more details (frequency, pack- age, accuracy...). figure 63. typical application with a crystal or ceramic resonator notes: 1. the oscillator selection can be opt imized in terms of supply current usi ng an high quality resonat or with small r s value. refer to crystal/ceramic resonator manufacturer for more details. 2. data based on characterisation results, not tested in production. symbol parameter conditions min max unit f osc oscillator frequency 1) lp: low power oscillator mp: medium power oscillator ms: medium speed oscillator hs: high speed oscillator 1 >2 >4 >8 2 4 8 16 mhz r f feedback resistor 2) 20 40 k ? c l1 c l2 recommended load capacitance ver- sus equivalent serial resistance of the crystal or ceramic resonator (r s ) r s =200 ? lp oscillator r s =200 ? mp oscillator r s =200 ? ms oscillator r s =100 ? hs oscillator 22 22 18 15 56 46 33 33 pf symbol parameter conditions typ max unit i 2 osc2 driving current v in =v ss lp oscillator mp oscillator ms oscillator hs oscillator 80 160 310 610 150 250 460 910 a osc2 osc1 f osc c l1 c l2 i 2 r f st72xxx resonator when resonator with integrated capacitors 1
st7232a 120/154 clock and timing characteristics (cont?d) notes: 1. resonator characteristics given by the ceramic resonator manufacturer. 2. t su(osc) is the typical oscillator start-up time measured between v dd =2.8v and the fetch of the first instruction (with a quick v dd ramp-up from 0 to 5v (<50 s). 3. resonators all have different characte ristics. contact the manufacturer to obt ain the appropriate values of external components and to verify oscillator performance. 4. 3rd overtone resonators r equire specific validation by the resonator manufacturer. oscil. typical ceramic resonators (information for guidance only) c l1 [pf] c l2 [pf] t su(osc) [ms] 2) reference 3) freq. characteristic 1) ceramic lp murata csa2.00mg 2mhz ? f osc =[0.5% tolerance ,0.3% ? ta , 0.3% aging , x.x% correl ]22 22 4 mp csa4.00mg 4mhz ? f osc =[0.5% tolerance ,0.3% ? ta , 0.3% aging , x.x% correl ]22 22 2 ms csa8.00mtz 8mhz ? f osc =[0.5% tolerance ,0.5% ? ta , 0.3% aging , x.x% correl ]33 33 1 hs csa16.00mxz040 4) 16mhz ? f osc =[0.5% tolerance ,0.3% ? ta , 0.3% aging , x.x% correl ]33 33 0.7 1
st7232a 121/154 clock characteristics (cont?d) 12.5.4 pll characteristics note: 1. data characterized but not tested. the user must take the pll jitter into account in the application (for example in serial communication or sampling of high frequency signals). the pll jitter is a periodic effect, which is integrated over several cpu cycles. therefore the lo nger the period of the application sign al, the less it will be impacted by the pll jitter. figure 64 shows the pll jitter integrated on application signals in the range 125khz to 2mhz. at frequen- cies of less than 125khz, the jitter is negligible. figure 64. integrated pll jitter vs signal frequency 1 note 1: measurement conditions: f cpu = 8mhz. symbol parameter conditions min typ max unit f osc pll input frequency range 2 4 mhz ? f cpu / f cpu instantaneous pll jitter 1) f osc = 4 mhz. 0.7 2 % 0 0.2 0.4 0.6 0.8 1 1.2 4 mhz 2 mhz 1 mhz 500 khz 250 khz 125 khz application frequency +/-jitter (%) max typ 1
st7232a 122/154 12.6 memory characteristics 12.6.1 ram and hardware registers 12.6.2 flash memory notes: 1. minimum v dd supply voltage without losing data stored in ram (in halt mode or under reset) or in hardware reg- isters (only in halt mode). not tested in production. 2. data based on characterization results, not tested in production. 3. v pp must be applied only during the programming or erasi ng operation and not permanently for reliability reasons. 4. data based on simulation resu lts, not tested in production. symbol parameter conditions min typ max unit v rm data retention mode 1) halt mode (or reset) 1.6 v dual voltage hdflash memory symbol parameter conditions min 2) typ max 2) unit f cpu operating frequency read mode 0 8 mhz write / erase mode 1 8 v pp programming voltage 3) 4.5v v dd 5.5v 11.4 12.6 v i dd supply current 4) write / erase 0 ma i pp v pp current 4) read (v pp =12v) 200 a write / erase 30 ma t vpp internal v pp stabilization time 10 s t ret data retention t a =55c 20 years n rw write erase cycles t a =25c 100 cycles t prog t erase programming or erasing tempera- ture range -40 25 85 c 1
st7232a 123/154 12.7 emc characteristics susceptibility tests are pe rformed on a sample ba- sis during product characterization. 12.7.1 functional ems (electro magnetic susceptibility) based on a simple running application on the product (toggling 2 leds through i/o ports), the product is stressed by two electro magnetic events until a failure occurs (indicated by the leds). esd : electro-static discharge (positive and negative) is applied on all pins of the device until a functional disturba nce occurs. this test conforms with the iec 1000-4-2 standard. ftb : a burst of fast transient voltage (positive and negative) is applied to v dd and v ss through a 100pf capacitor, until a functional disturbance occurs. this test confor ms with the iec 1000-4- 4 standard. a device reset allows normal operations to be re- sumed. the test results are given in the table be- low based on the ems levels and classes defined in application note an1709. 12.7.1.1 designing hardened software to avoid noise problems emc characterization and optimization are per- formed at component level with a typical applica- tion environment and simplified mcu software. it should be noted that good emc performance is highly dependent on the user application and the software in particular. therefore it is recommended that the user applies emc software optimization and prequalification tests in relation with the emc level requested for his application. software recommendations: the software flowchart must include the manage- ment of runaway conditions such as: ? corrupted program counter ? unexpected reset ? critical data corruption (control registers...) prequalification trials: most of the common failures (unexpected reset and program counter corruption) can be repro- duced by manually forcing a low state on the re- set pin or the oscillator pins for 1 second. to complete these trials, esd stress can be ap- plied directly on the device, over the range of specification values. when unexpected behaviour is detected, the software can be hardened to pre- vent unrecoverable errors occurring (see applica- tion note an1015) . symbol parameter conditions level/ class v fesd voltage limits to be applied on any i/o pin to induce a functional disturbance rom device, v dd = 5v, t a = +25c, f o- sc = 8mhz conforms to iec 1000-4-2 4a flash device, v dd = 5v, t a = +25c, f o- sc = 8mhz conforms to iec 1000-4-2 4b v fftb fast transient voltage bur st limits to be applied through 100pf on v dd and v dd pins to induce a func- tional disturbance v dd = 5v, t a = +25c, f osc = 8mhz conforms to iec 1000-4-4 4a 1
st7232a 124/154 emc characteristics (cont?d) 12.7.2 electro magnetic interference (emi) based on a simple application running on the product (toggling 2 leds through the i/o ports), the product is monitored in terms of emission. this emission test is in line with the norm sae j 1752/ 3 which specifies the board and the loading of each pin. notes: 1. data based on characterization results, not tested in production. 2. refer to application note an1709 for data on other package types. 3. under completion symbol parameter conditions device/ package monitored frequency band max vs. [f osc /f cpu ] unit 8/4mhz 16/8mhz s emi peak level v dd = 5v, t a = +25c conforming to sae j 1752/3 flash/tqfp32 0.1mhz to 30mhz 25 27 db v 30mhz to 130mhz 30 36 130mhz to 1ghz 18 23 sae emi level 3.0 3.5 - rom/tqfp32 3) 0.1mhz to 30mhz 25 27 db v 30mhz to 130mhz 30 36 130mhz to 1ghz 18 23 sae emi level 3.0 3.5 - 1
st7232a 125/154 emc characteristics (cont?d) 12.7.3 absolute maximum ratings (electrical sensitivity) based on three different tests (esd, lu and dlu) using specific measuremen t methods, the product is stressed in order to determine its performance in terms of electrical sensitiv ity. for more details, re- fer to the application note an1181. 12.7.3.1 electro-static discharge (esd) electro-static discharges (a positive then a nega- tive pulse separated by 1 second) are applied to the pins of each sample according to each pin combination. the sample size depends on the number of supply pins in the device (3 parts*(n+1) supply pin). two models can be simulated: human body model and machine model. this test con- forms to the jesd22-a114a/a115a standard. absolute maximum ratings notes: 1. data based on characterization results, not tested in production. 12.7.3.2 static and dynamic latch-up lu : 3 complementary static tests are required on 10 parts to assess the latch-up performance. a supply overvoltage (applied to each power supply pin) and a current injection (applied to each input, output and configurable i/o pin) are performed on each sample. this test conforms to the eia/jesd 78 ic latch-up standard. for more details, refer to the application note an1181. dlu : electro-static discharges (one positive then one negative test) are applied to each pin of 3 samples when the micro is running to assess the latch-up performance in dynamic mode. power supplies are set to the typical values, the oscillator is connected as near as possible to the pins of the micro and the component is put in reset mode. this test conforms to the iec1 000-4-2 and saej1752/3 standards. for more details, refer to the application note an1181. electrical sensitivities notes: 1. class description: a class is an stmicr oelectronics internal specif ication. all its limits are higher than the jedec spec- ifications, that means when a device belongs to class a it exceeds the jedec standar d. b class strictly covers all the jedec criteria (int ernational standard). symbol ratings conditions maximum value 1) unit v esd(hbm) electro-static discharge voltage (human body model) t a = +25c 2000 v v esd(mm) electro-static discharge voltage (machine model) t a = +25c 200 v esd(cd) electro-static discharge voltage (charged device model) t a = +25c 250 symbol parameter conditions class 1) lu static latch-up class t a = +25c t a = +85c a a dlu dynamic latch-up class v dd = 5.5v, f osc = 4mhz, t a = +25c a 1
st7232a 126/154 12.8 i/o port pin characteristics 12.8.1 general characteristics subject to general operating conditions for v dd , f osc , and t a unless otherwise specified. notes: 1. data based on characterization results, not tested in production. 2. hysteresis voltage between schmitt tr igger switching levels. based on c haracterization results, not tested. 3. when the current limitation is not possible, the v in maximum must be respected, otherwise refer to i inj(pin) specifica- tion. a positive injection is induced by v in >v dd while a negative injection is induced by v in st7232a 127/154 i/o port pin characteristics (cont?d) 12.8.2 output driving current subject to general operating conditions for v dd , f cpu , and t a unless otherwise specified. figure 67. typical v ol at v dd =5v (std. ports) figure 68. typ. v ol at v dd =5v (high-sink ports) figure 69. typical v oh at v dd =5v notes: 1. the i io current sunk must always respect t he absolute maximum rating specified in section 12.2.2 and the sum of i io (i/o ports and control pi ns) must not exceed i vss . 2. the i io current sourced must always respect t he absolute maximum rating specified in section 12.2.2 and the sum of i io (i/o ports and control pins) must not exceed i vdd . true open drain i/o pins do not have v oh . symbol parameter conditions min max unit v ol 1) output low level voltage for a standard i/o pin when 8 pins are sunk at same time (see figure 67 ) v dd =5v i io =+5ma 1.2 v i io =+2ma 0.5 output low level voltage for a high sink i/o pin when 4 pins are sunk at same time (see figure 68 and figure 70 ) i io =+20ma, t a 85c t a > 85c 1.3 1.5 i io =+8ma 0.6 v oh 2) output high level voltage for an i/o pin when 4 pins are sourced at same time (see figure 69 and figure 72 ) i io =-5ma, t a 85c t a > 85c v dd -1.4 v dd -1.6 i io =-2ma v dd -0.7 0 0.2 0.4 0.6 0.8 1 1.2 0 0.005 0.01 0.015 ii o(a ) vol (v) at vdd=5v ta =14 0c " ta =95 c ta =25 c ta =-45 c 51015 i io (ma) 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.01 0.02 0.03 ii o (a ) vol(v) at vdd=5v ta= 140c ta= 95 c ta= 25 c ta= -45c 10 20 30 i io (ma) 2 2.5 3 3.5 4 4.5 5 5.5 -0.01 -0.008 -0.006 -0.004 -0.002 0 ii o ( a ) vdd-voh (v) at vdd=5v v dd= 5v 140c min v dd= 5v 95c min v dd= 5v 25c min v dd= 5v -45c min -10 -8 -6 -4 -2 0 i io (ma) 1
st7232a 128/154 i/o port pin characteristics (cont?d) figure 70. typical v ol vs. v dd (std. ports) figure 71. typical v ol vs. v dd (high-sink ports) figure 72. typical v oh vs. v dd 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 2 2.5 3 3.5 4 4.5 5 5.5 6 vdd(v) vol(v) at iio=5ma ta= -4 5c ta= 25c ta= 95c ta= 140 c 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 2 2.5 3 3.5 4 4.5 5 5.5 6 vdd ( v ) vol(v) at iio=2ma ta=-45c ta=25c ta=95c ta=140c 0 0.1 0.2 0.3 0.4 0.5 0.6 22.533.544.555.56 vdd(v) vol(v) at iio=8ma ta= 140c ta=95c ta=25c ta=-45c 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 2 2.5 3 3.5 4 4.5 5 5.5 6 v dd(v ) vol(v) at iio=20ma ta= 140c ta = 95 c ta = 25 c ta=-45c 0 1 2 3 4 5 6 2 2.5 3 3.5 4 4.5 5 5.5 6 vdd(v) vdd-voh(v) at iio=-5m a ta=-45c ta= 25c ta= 95c ta= 140c 2 2.5 3 3.5 4 4.5 5 5.5 2 2.5 3 3.5 4 4.5 5 5.5 6 vdd(v) vdd-voh(v) at iio=-2ma ta= -45c ta= 25c ta= 95c ta= 140c 1
st7232a 129/154 12.9 control pin characteristics 12.9.1 asynchronous reset pin subject to general operating conditions for v dd , f cpu , and t a unless otherwise specified. notes: 1. data based on characterization results, not tested in production. 2. hysteresis voltage between schmit t trigger switching levels. 3. the i io current sunk must always respect t he absolute maximum rating specified in section 12.2.2 and the sum of i io (i/o ports and control pi ns) must not exceed i vss . 4. to guarantee the reset of the device, a mi nimum pulse has to be applied to the reset pin. all short pulses applied on the reset pin with a duration below t h(rstl)in can be ignored. 5. the reset network (the resistor and tw o capacitors) protects the device against parasitic resets, especially in noisy en- vironments. 6. data guaranteed by design, not tested in production. symbol parameter conditions min typ max unit v hys schmitt trigger voltage hysteresis 2) 2.5 v il input low level voltage 1) 0.16xv dd v v ih input high level voltage 1) 0.85xv dd v ol output low level voltage 3) v dd =5v i io =+2ma 0.2 0.5 v i io driving current on reset pin 2 ma r on weak pull-up equiva lent resistor v dd =5v 20 30 120 k ? t w(rstl)out generated reset pulse duration i nternal reset sources 20 30 42 6) s t h(rstl)in external reset pulse hold time 4) 2.5 s t g(rstl)in filtered glitch duration 5) 200 ns 1
st7232a 130/154 control pin characteristics (cont?d) figure 73. r eset pin protection 1)2)3)4) 1. the reset network protects t he device against parasitic resets. 2. the output of the external reset circuit must have an open-dr ain output to drive the st7 re set pad. otherwise the device can be damaged when the st7 generates an internal reset (watchdog). 3. whatever the reset source is (i nternal or exter nal), the user must ensure that the level on the reset pin can go below the v il max. level specified in section 12.9.1 . otherwise the reset will not be taken into account internally. 4. because the reset circuit is designed to al low the internal reset to be output in the reset pin, the user must ensure that the current sunk on the reset pin (by an external pull-up for example) is less than the absolute maximum value specified for i inj(reset) in section 12.2.2 on page 112 . 0.01 f 0.01 f v dd external reset circuit user v dd 4.7k ? required recommended for emc st72xxx pulse generator filter r on v dd watchdog internal reset 1
st7232a 131/154 control pin characteristics (cont?d) 12.9.2 iccsel/v pp pin subject to general operating conditions for v dd , f cpu , and t a unless otherwise specified. figure 74. two typical applications with iccsel/v pp pin 2) notes: 1. data based on design simulation and/or technology characteristics, not tested in production. 2. when icc mode is not required by the application iccsel/v pp pin must be tied to v ss . symbol parameter conditions min max unit v il input low level voltage 1) flash versions v ss 0.2 v rom versions v ss 0.3xv dd v ih input high level voltage 1) flash versions v dd -0.1 12.6 rom versions 0.7xv dd v dd i l input leakage current v in =v ss 1 a iccsel/v pp st72xxx 10k ? programming tool v pp st72xxx 1
st7232a 132/154 12.10 timer peripheral characteristics subject to general operating conditions for v dd , f osc , and t a unless otherwise specified. refer to i/o port characteristics for more details on the input/output alternate function characteristics (out- put compare, input capture, external clock, pwm output...). data based on design simulation and/or characterisation results, not tested in production. 12.10.1 16-bit timer symbol parameter conditions min typ max unit t w(icap)in input capture pulse time 1 t cpu t res(pwm) pwm resolution time 2t cpu f cpu =8mhz 250 ns f ext timer external clock frequency 0 f cpu /4 mhz f pwm pwm repetition rate 0 f cpu /4 mhz res pwm pwm resolution 16 bit 1
st7232a 133/154 12.11 communication interface characteristics 12.11.1 spi - serial peripheral interface subject to general operating conditions for v dd , f cpu , and t a unless otherwise specified. data based on design simulation and/or characterisation results, not tested in production. when no communication is on-going the data output line of the spi (mosi in master mode, miso in slave mode) has its alternate function ca pability released. in this case, t he pin status depen ds on the i/o port configuration. refer to i/o port characteristics for more details on the input/output alternate function char- acteristics (ss , sck, mosi, miso). figure 75. spi slave timing diagram with cpha=0 1) notes: 1. measurement points are done at cmos levels: 0.3xv dd and 0.7xv dd . symbol parameter conditions min max unit f sck 1/t c(sck) spi clock frequency master f cpu =8mhz f cpu /128 0.0625 f cpu /4 2 mhz slave f cpu =8mhz 0 f cpu /2 4 t r(sck) t f(sck) spi clock rise and fall time see i/o port pin description t su(ss ) ss setup time slave 120 ns t h(ss ) ss hold time slave 120 t w(sckh) t w(sckl) sck high and low time master slave 100 90 t su(mi) t su(si) data input setup time master slave 100 100 t h(mi) t h(si) data input hold time master slave 100 100 t a(so) data output access time slave 0 120 t dis(so) data output disable time slave 240 t v(so) data output valid time slave (after enable edge) 90 t h(so) data output hold time 0 t v(mo) data output valid time master (before capture edge) 0.25 t cpu t h(mo) data output hold time 0.25 ss input sck input cpha=0 mosi input miso output cpha=0 t c(sck) t w(sckh) t w(sckl) t r(sck) t f(sck) t v(so) t a(so) t su(si) t h(si) msb out msb in bit6 out lsb in lsb out seenote2 cpol=0 cpol=1 t su(ss ) t h(ss ) t dis(so) t h(so) see note 2 bit1 in 1
st7232a 134/154 communication interface characteristics (cont?d) figure 76. spi slave timing diagram with cpha=1 1) figure 77. spi master timing diagram 1) notes: 1. measurement points are done at cmos levels: 0.3xv dd and 0.7xv dd . 2. when no communication is on-going the dat a output line of the spi (mosi in mast er mode, miso in slave mode) has its alternate function capability rel eased. in this case, the pin status depends of the i/o port configuration. ss input sck input cpha=1 mosi input miso output cpha=1 t w(sckh) t w(sckl) t r(sck) t f(sck) t a(so) t su(si) t h(si) msb out bit6 out lsb out see cpol=0 cpol=1 t su(ss ) t h(ss ) t dis(so) t h(so) see note 2 note 2 t c(sck) hz t v(so) msb in lsb in bit1 in ss input sck input cpha=0 mosi output miso input cpha=0 cpha=1 cpha=1 t c(sck) t w(sckh) t w(sckl) t h(mi) t su(mi) t v(mo) t h(mo) msb in msb out bit6 in bit6 out lsb out lsb in seenote2 seenote2 cpol=0 cpol=1 cpol=0 cpol=1 t r(sck) t f(sck) 1
st7232a 135/154 12.12 10-bit adc characteristics subject to general operating conditions for v dd , f cpu , and t a unless otherwise specified. notes: 1. any added external serial resist or will downgrade the adc accuracy (es pecially for resistance greater than 10k ? ). data based on characterization result s, not tested in production. 2.injecting negative current on any of t he analog input pins signific antly reduces the accuracy of any conversion being performed on any analog input. analog pins can be protected agai nst negative injection by adding a schottky diode (pin to ground). injecting negative current on digital input pins degrades adc accuracy especially if performed on a pin close to the analog input pins. any positive injection current wi thin the limits specified for i inj(pin) and i inj(pin) in section 12.8 does not affect the adc accuracy. symbol parameter conditions min typ max unit f adc adc clock frequency 0.4 2 mhz v aref analog reference voltage 0.7*v dd v aref v dd 3.8 v dd v v ain conversion voltage range 1) v ssa v aref i lkg positive input leakage current for analog input 2) -40c t a + 85c 250 na r ain external input impedance see figure 78 and figure 79 k ? c ain external capacitor on analog input pf f ain variation freq. of analog input signal hz c adc internal sample and hold capacitor 12 pf t adc conversion time (sample+hold) f cpu =8mhz, speed=0 f adc =2mhz 7.5 s t adc - no of sample capacitor loading cycles - no. of hold conversion cycles 4 11 1/f adc 1
st7232a 136/154 adc characteristics (cont?d) figure 78. r ain max. vs f adc with c ain =0pf 1) figure 79. recommended c ain & r ain values. 2) figure 80. typical a/d converter application notes: 1. c parasitic represents the capacitance of the pcb (dependent on soldering and pcb layout quality) plus the pad ca- pacitance (3pf). a high c parasitic value will downgrade conversion accuracy. to remedy this, f adc should be reduced. 2. this graph shows that depending on the input signal variation (f ain ), c ain can be increased for stabilization time and decreased to allow the use of a larger serial resistor (r ain) . 0 5 10 15 20 25 30 35 40 45 0103070 c parasitic (pf) max. r ain (kohm) 2 mhz 1 mhz 0.1 1 10 100 1000 0.01 0.1 1 10 f ain (khz) max. r ain (kohm) cain 10 nf cain 22 nf cain 47 nf ainx st72xxx v dd i l 1 a v t 0.6v v t 0.6v c adc 12pf v ain r ain 10-bit a/d conversion 2k ?( max ) c ain 1
st7232a 137/154 adc characteristics (cont?d) 12.12.1 analog power supply and reference pins depending on the mcu pin count, the package may feature separate v aref and v ssa analog power supply pins. these pi ns supply power to the a/d converter cell and function as the high and low reference voltages for the conversion. in some packages, v aref and v ssa pins are not available (refer to section 2 on page 8 ). in this case the an- alog supply and reference pads are internally bonded to the v dd and v ss pins. separation of the digital and analog power pins al- low board designers to improve a/d performance. conversion accuracy can be impacted by voltage drops and noise in the event of heavily loaded or badly decoupled power supply lines (see section 12.12.2 general pcb design guidelines ). 12.12.2 general pcb design guidelines to obtain best results, some general design and layout rules should be followed when designing the application pcb to sh ield the noise-sensitive, analog physical interface from noise-generating cmos logic signals. ? use separate digital and analog planes. the an- alog ground plane should be connected to the digital ground plane via a single point on the pcb. ? filter power to the analog power planes. it is rec- ommended to connect capacitors, with good high frequency characteristics, between the power and ground lines, placing 0.1f and optionally, if needed 10pf capacitors as close as possible to the st7 power supply pins and a 1 to 10f ca- pacitor close to the power source (see figure 81 ). ? the analog and digital power supplies should be connected in a star nework. do not use a resis- tor, as v aref is used as a reference voltage by the a/d converter and any resistance would cause a voltage drop and a loss of accuracy. ? properly place components and route the signal traces on the pcb to shield the analog inputs. analog signals paths should run over the analog ground plane and be as short as possible. isolate analog signals from digital signals that may switch while the analog inputs are being sampled by the a/d converter. do not toggle digital out- puts on the same i/o port as the a/d input being converted. figure 81. power supply filtering v ss v dd v dd st72xxx v aref v ssa power supply source st7 digital noise filtering external noise filtering 1 to 10 f 0.1 f 0.1 f 1
st7232a 138/154 10-bit adc characteristics (cont?d) 12.12.3 adc accuracy conditions: v dd =5v 1) notes: 1. adc accuracy vs. negative injection current: injecting negative current may reduce the accuracy of the conversion being performed on another analog input. the effect of negative injection current on robust pins is specified in section 12.12 . any positive injection current wi thin the limits specified for i inj(pin) and i inj(pin) in section 12.8 does not affect the adc accuracy. 2. data based on characterization results, monitored in pr oduction to guarantee 99.73% with in max value from -40c to 125c ( 3 distribution limits). figure 82. adc accuracy characteristics symbol parameter conditions typ max 2) unit |e t | total unadjusted error 1) 46 lsb |e o | offset error 1) 35 |e g | gain error 1) 0.5 4.5 |e d | differential linearity error 1) cpu in run mode @ f adc = 2 mhz. 1.5 4.5 |e l | integral linearity error 1) cpu in run mode @ f adc = 2 mhz. 1.5 4.5 e o e g 1lsb ideal 1lsb ideal v aref v ssa ? 1024 -------------------------------------------- = v in (lsb ideal ) (1) example of an actual transfer curve (2) the ideal transfer curve (3) end point correlation line e t =total unadjusted error: maximum deviation between the actual and the ideal transfer curves. e o =offset error: deviation between the first actual transition and the first ideal one. e g =gain error: deviation between the last ideal transition and the last actual one. e d =differential linearity error: maximum deviation between actual steps and the ideal one. e l =integral linearity error: maximum deviation between any actual transition and the end point correlation line. digital result adcdr 1023 1022 1021 5 4 3 2 1 0 7 6 1234567 1021 1022 1023 1024 (1) (2) e t e d e l (3) v aref v ssa 1
st7232a 139/154 13 package characteristics 13.1 package mechanical data figure 83. 32-pin thin quad flat package figure 84. 32-pin plastic dual in-line package, shrink 400-mil width dim. mm inches min typ max min typ max a 1.60 0.063 a1 0.05 0.15 0.002 0.006 a2 1.35 1.40 1.45 0.053 0.055 0.057 b 0.30 0.37 0.45 0.012 0.015 0.018 c 0.09 0.20 0.004 0.008 d 9.00 0.354 d1 7.00 0.276 e 9.00 0.354 e1 7.00 0.276 e 0.80 0.031 0 3.5 7 0 3.5 7 l 0.45 0.60 0.75 0.018 0.024 0.030 l1 1.00 0.039 number of pins n 32 h c l l1 b e a1 a2 a e e1 d d1 dim. mm inches min typ max min typ max a 3.56 3.76 5.08 0.140 0.148 0.200 a1 0.51 0.020 a2 3.05 3.56 4.57 0.120 0.140 0.180 b 0.36 0.46 0.58 0.014 0.018 0.023 b1 0.76 1.02 1.40 0.030 0.040 0.055 c 0.20 0.25 0.36 0.008 0.010 0.014 d 27.43 28.45 1.080 1.100 1.120 e 9.91 10.41 11.05 0.390 0.410 0.435 e1 7.62 8.89 9.40 0.300 0.350 0.370 e 1.78 0.070 ea 10.16 0.400 eb 12.70 0.500 ec 1.40 0.055 l 2.54 3.05 3.81 0.100 0.120 0.150 number of pins n 32 d b2 b e a a1 a2 l e1 e ec c ea eb 1
st7232a 140/154 13.2 thermal characteristics notes: 1. the power dissipation is obtained from the formula p d =p int +p port where p int is the chip internal power (i dd xv dd ) and p port is the port power dissipati on determined by the user. 2. the average chip-junction temperatur e can be obtained from the formula t j = t a + p d x rthja. symbol ratings value unit r thja package thermal resistance (junction to ambient) tqfp32 7x7 sdip32 400mil 70 tbd c/w p d power dissipation 1) 500 mw t jmax maximum junction temperature 2) 150 c 1
st7232a 141/154 13.3 soldering information in accordance with the rohs european directive, all stmicroelectronics packages will be converted in 2005 to lead-free technology, named eco- pack tm (for a detailed roadmap, please refer to pcn crp/04/744 "lead-free conversion program - compliance with rohs", issued november 18th, 2004). ecopack tm packages are qualified according to the jedec std-020b compliant soldering profile. detailed information on the stmicroelectronic ecopack tm transition program is available on www.st.com/stonline/le adfree/, with specific technical application notes covering the main technical aspects related to lead-free conversion (an2033, an2034, an2035, an2036). backward and forward compatibility: the main difference between pb and pb-free sol- dering process is the temperature range. ? ecopack tm tqfp, sdip and so packages are fully compatible with lead (pb) containing soldering process (see application note an2034) ? tqfp, sdip and so pb-packages are compati- ble with lead-free soldering process, neverthe- less it's the customer's duty to verify that the pb- packages maximum temperature (mentioned on the inner box label) is compatible with their lead- free soldering temperature. table 26. soldering compatibility (wave and reflow soldering process) * assemblers must verify that the pb-package maximum temperature (mentioned on the inner box label) is compatible with their l ead-free soldering process. package plating material devices pb solder paste pb-free solder paste sdip & pdip sn (pure tin) yes yes * tqfp and so nipdau (nickel-palladium-gold) yes yes * 1
st7232a 142/154 14 st7232a device configuration and ordering information each device is available for production in user pro- grammable versions (flash) as well as in factory coded versions (rom). st7232a devices are rom versions. st72p32a devices are factory advanced service technique rom (fastrom) versions: they are factory-programmed hdflash devices. flash devices are shipped to customers with a default content (ffh), while rom factory coded parts contain the code supplied by the cus- tomer. this implies that flash devices have to be configured by the customer using the option bytes while the rom devices are factory-configured. 14.1 flash option bytes the option bytes allows the hardware configura- tion of the microcontroller to be selected. they have no address in the memory map and can be accessed only in programming mode (for example using a standard st7 programming tool). the de- fault content of the flash is fixed to ffh. to pro- gram directly the flash devices using icp, flash devices are shipped to customers with an internal clock source. in masked rom devices, the option bytes are fixed in hardware by the rom code (see option list). option byte 0 opt7= wdg halt watchdog reset on halt this option bit determines if a reset is generated when entering halt mode while the watchdog is active. 0: no reset generation when entering halt mode 1: reset generation when entering halt mode opt6= wdg sw hardware or software watchdog this option bit selects the watchdog type. 0: hardware (watch dog always enabled) 1: software (watchdog to be enabled by software) opt5:1 = reserved, must be kept at default value. opt0= fmp_r flash memory read-out protection read-out protection, when selected, provides a protection against program memory content ex- traction and against write access to flash memo- ry. erasing the option bytes when the fmp_r option is selected causes the wh ole user memory to be erased first, and the device can be reprogrammed. refer to section 7.3.1 on page 37 and the st7 flash programming reference manual for more details. 0: read-out protection enabled 1: read-out protection disabled static option byte 0 70 static option byte 1 70 wdg reserved reserved reserved reserved reserved fmp_r pkg1 rstc osctype oscrange plloff halt sw 10 2 10 default111001110 1 10 1 1 1 1 1
st7232a 143/154 st7232a device configuratio n and ordering information (cont?d) option byte 1 opt7= pkg1 pin package selection bit this option bit selects the package. note: on the chip, each i/o port has 8 pads. pads that are not bonded to external pins are in input pull-up configuration after reset. the configuration of these pads must be kept at reset state to avoid added current consumption. opt6 = rstc reset clock cycle selection this option bit selects the number of cpu cycles applied during the reset ph ase and when exiting halt mode. for resonator o scillators, it is advised to select 4096 due to th e long crystal stabilization time. 0: reset phase with 4096 cpu cycles 1: reset phase with 256 cpu cycles opt5:4 = osctype[1:0] oscillator type these option bits select the st7 main clock source type. opt3:1 = oscrange[2:0] oscillator range when the resonator oscilla tor type is selected, these option bits select the resonator oscillator current source corresponding to the frequency range of the used resonator. otherwise, these bits are used to select the normal operating frequency range. opt0 = pll off pll activation this option bit activates the pll which allows mul- tiplication by two of the main input clock frequency. the pll is guaranteed only with an input frequen- cy between 2 and 4mhz. 0: pll x2 enabled 1: pll x2 disabled caution : the pll can be enabled only if the ?osc range? (opt3:1) bits are configured to ?mp - 2~4mhz?. otherwise, the device functionali- ty is not guaranteed. version selected package pkg1 k tqfp32 / sdip32 0 clock source osctype 10 resonator oscillator 0 0 reserved 0 1 reserved 1 0 external source 1 1 typ. freq. range oscrange 210 lp 1~2mhz 0 0 0 mp 2~4mhz 0 0 1 ms 4~8mhz 0 1 0 hs 8~16mhz 0 1 1 1
st7232a 144/154 st7232a device configuratio n and ordering information (cont?d) 14.2 rom device ordering inform ation and transfer of customer code rom devices can be ordered in any combination of memory size and temperature range with the types given in figure 85 and by completing the op- tion list on the next page. rom customer code is made up of the rom con- tents and the list of the selected options (if any). the rom contents are to be sent with the s19 hexadecimal file generated by the development tool. all unused bytes must be set to ffh. refer to application note an1635 for information on the counter listing returned by st after code has been transferred. the stmicroelectronics sales organization will be pleased to provide detailed information on con- tractual points. figure 85. rom factory coded device types device package version xxx / code name (defined by stmicroelectronics) 1= standard 0 to +70 c 5= standard -10 to +85 c 6= standard -40 to +85 c a = automotive -40 to +85 c t= plastic thin quad flat pack b= plastic dual in line st7232ak1, st7232ak2 1
st7232a 145/154 st7232a device configuratio n and ordering information (cont?d) st7232a microcontr oller option list (last updated april 2005) customer: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . address: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . contact: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . phone no: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . reference/rom code* : . . . . . . . . . . . . . . . . . . . . . . . . . . . *the rom code name is assigned by stmicroelectronics. rom code must be sent in .s19 format . .hex extension cannot be processed. device type/memory size/package (check only one option): conditioning (check only one option): power supply range: [ ] 3.8 to 5.5v version/temp. range (do not check for die product). please refer to datasheet for specific sales conditions: special marking: [ ] no [ ] yes "_ _ _ _ _ _ _ _ _ _ " (tqfp32 7 char., other pkg. 10 char. max) authorized characters ar e letters, digits, '.', '-', '/' and spaces only. clock source selection: [ ] resonator: [ ] lp: low power resonator (1 to 2 mhz) [ ] mp: medium power resonator (2 to 4 mhz) [ ] ms: medium speed resonator (4 to 8 mhz) [ ] hs: high speed resonator (8 to 16 mhz) [ ] external clock (1) pll (1) [ ] disabled [ ] enabled reset delay [ ] 256 cycles [ ] 4096 cycles watchdog selection: [ ] software activation [ ] hardware activation watchdog reset on halt: [ ] reset [ ] no reset readout protection (2): [ ] disabled [ ] enabled date . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . signature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . (1) pll not supported with external clock source (2) the readout protection binary valu e is inverted between rom and flash pr oducts. the option byte checksum will differ between rom and flash. --------------------------------- rom device: --------------------------------- | | ------------------------------------- 4k ------------------------------------- | | ------------------------------------- 8k ------------------------------------- tqfp32: | [ ] st7232ak1t | [ ] st7232ak2t dip32: | [ ] st7232ak1b | [ ] st7232ak2b --------------------------------- die form: --------------------------------- | | -------------------------------------- 4k --------------------------------------- | | -------------------------------------- 8k --------------------------------------- 32-pin: | [ ] | [ ] ------------------------------------------------------------------------ packaged product ------------------------------------------------------------------------ | | ----------------------------------------------------- die product (dice tested at 25c only) ----------------------------------------------------- [ ] tape & reel [ ] tray | [ ] tape & reel | [ ] inked wafer | [ ] sawn wafer on sticky foil -------------------- standard -------------------- | | ------------------- automotive ------------------- || --------------------------------------- temp. range --------------------------------------- [ ] | | 0c to +70c [ ] | | -10c to +85c [ ] | [ ] | -40c to +85c 1
st7232a 146/154 device configuration an d ordering information (cont?d) 14.3 version-specific sales conditions to satisfy the different customer requirements and to ensure that st stan dard microcontrollers will consistently meet or exceed the expectations of each market segment, the codification system for standard microcontrollers clearly distinguishes products intended for use in automotive environ- ments, from products intended for use in non-auto- motive environments. it is the responsibility of the customer to select the appropriate product for his application. 14.4 flash device ordering information table 27. st72f32a flash order codes part number version package flash memory (kbytes) temp. range st72f32ak2ta automotive tqfp32 8 -40c +85c st72f32ak2t6 standard tqfp32 8 -40c +85c st72f32ak2t1 0c +70c st72f32ak2b6 sdip32 -40c +85c st72f32ak2b1 0c +70c 1
st7232a 147/154 14.5 development tools stmicroelectronics offers a range of hardware and software development tools for the st7 micro- controller family. full details of tools available for the st7 from third party manufacturers can be ob- tain from the stmicroelectronics internet site: ? http//:mcu.st.com. tools from these manufacturers include c compli- ers, emulators and gang programmers. emulators two types of emulators are available from st for the st7232a family: st7 dvp3 entry-level emulator offers a flexible and modular debugging and programming solution. sdip42 & sdip32 probes/adapters are included, other packages need a specific connection kit (refer to table 28 ) st7 emu3 high-end emulator is delivered with everything (probes, teb, adapters etc.) needed to start emulating the st7232x family. to configure it to emulate other st7 subfamily devices, the active probe for the st7emu3 can be changed and the st7emu3 probe is designed for easy interchange of tebs (target emulation board). see table 28 . in-circuit debugging kit two configurations are available from st: stxf521-ind/usb: low-cost in-circuit debugging kit from softec microsystems. includes stx-indart/usb board (usb port) and a specific demo board for st72521 (tqfp64) stxf-indart flash programming tools st7-stick st7 in-circuit communication kit, a complete software/hardware package for programming st7 flash devices. it connects to a host pc parallel port and to the target board or socket board via st7 icc connector. icc socket boards provide an easy to use and flexible means of programming st7 flash devices. they can be connected to any tool that supports the st7 icc interface, such as st7 emu3, st7-dvp3, indart, st7-stick, or many third-party development tools. evaluation board st7232x-eval with i cc connector for programming capabilit y. provides direct connection to st7-dvp3 emulator. supplied with daughter boards (core module) for st72f32a chips. table 28. stmicroelectronics development tools note 1: add suffix /eu, /uk, /us for the power supply of your region. supported products emulation programming st7 dvp3 series st7 emu3 series icc socket board emulator connection kit emulator active probe & t.e.b. st7232a st7mdt20-dvp3 st7mdt20-t32/ dvp st7mdt20j- emu3 st7mdt20j-teb st7sb20j/xx 1 1
st7232a 148/154 14.5.1 socket and emulator adapter information for information on the type of socket that is sup- plied with the emulator, refer to the suggested list of sockets in table 29 . note: before designing the board layout, it is rec- ommended to check the overall dimensions of the socket as they may be greater than the dimen- sions of the device. for footprint and other mechanical information about these sockets and adapters, refer to the manufacturer?s datasheet (www.ironwoodelec- tronics.com for tqfp32 7 x 7). table 29. suggested list of socket types device socket (supplied with st7mdt20j-emu3) emulator adapter (supplied with st7mdt20j-emu3) tqfp32 7 x 7 ironwood sf-qfe32sa-l-01 ironwood sk-uga06/32a-01 1
st7232a 149/154 14.6 st7 application notes table 30. st7 application notes identification description application examples an1658 serial numbering implementation an1720 managing the read-out protection in flash microcontrollers an1755 a high resolution/precision thermometer using st7 and ne555 example drivers an 969 sci communication between st7 and pc an 970 spi communication between st7 and eeprom an 972 st7 software spi master communication an 973 sci software communication with a pc using st72251 16-bit timer an 974 real time clock with st7 timer output compare an 976 driving a buzzer through st7 timer pwm function an 979 driving an analog keyboard with the st7 adc an 980 st7 keypad decoding techniques, implementing wake-up on keystroke an1041 using st7 pwm signal to generate analog output (sinuso?d) an1044 multiple interrupt sources management for st7 mcus an1046 uart emulation software an1047 managing reception errors with the st7 sci peripherals an1048 st7 software lcd driver an1078 pwm duty cycle switch implementing true 0% & 100% duty cycle an1445 emulated 16 bit slave spi an1504 starting a pwm signal directly at high level using the st7 16-bit timer general purpose an1476 low cost power supply for home appliances an1709 emc design for st microcontrollers an1752 st72324 quick reference note product evaluation an 910 performance benchmarking an 990 st7 benefits versus industry standard an1150 benchmark st72 vs pc16 an1151 performance comparison between st72254 & pc16f876 an1278 lin (local interconnect network) solutions product migration an1131 migrating applications from st72511/311/214/124 to st72521/321/324 product optimization an 982 using st7 with ceramic resonator an1014 how to minimize the st7 power consumption an1015 software techniques for improving microcontroller emc performance an1070 st7 checksum self-checking capability an1181 electrostatic discharge sensitive measurement an1502 emulated data eeprom with st7 hdflash memory an1530 accurate timebase for low-cost st7 applications with internal rc oscilla- tor an1636 understanding and minimizing adc conversion errors programming and tools an 978 st7 visual develop software key debugging features 1
st7232a 150/154 an 983 key features of the cosmic st7 c-compiler package an 985 executing code in st7 ram an 986 using the indirect addressing mode with st7 an 987 st7 serial test controller programming an 988 starting with st7 assembly tool chain an 989 getting started with the st7 hiware c toolchain an1039 st7 math utility routines an1064 writing optimized hiware c language for st7 an1106 translating assembly code from hc05 to st7 an1446 using the st72521 emulator to debug a st72324 target application an1478 porting an st7 panta project to codewarrior ide an1575 on-board programming methods for xflash and hdflash st7 mcus an1576 in-application programming (iap) drivers for st7 hdflash or xflash mcus an1635 st7 customer rom code release information an1754 data logging program for testing st7 applications via icc an1796 field updates for flash based st7 applications using a pc comm port system optimization an1711 software techniques for compensating st7 adc errors table 30. st7 application notes identification description 1
st7232a 151/154 15 known limitations 15.1 all flash and rom devices 15.1.1 safe connection of osc1/osc2 pins the osc1 and/or osc2 pins must not be left un- connected otherwise the st7 main oscillator may start and, in this configuration, could generate an f osc clock frequency in excess of the allowed maximum (>16mhz.), putting the st7 in an un- safe/undefined state. refer to section 6.2 on page 22 . 15.1.2 unexpected reset fetch if an interrupt request occu rs while a "pop cc" in- struction is executed, the interrupt controller does not recognise the source of the interrupt and, by default, passes the reset vector address to the cpu. workaround to solve this issue, a "pop cc" instruction must always be preceded by a "sim" instruction. 15.1.3 clearing active interrupts outside interrupt routine when an active interrupt request occurs at the same time as the related flag is being cleared, an unwanted reset may occur. note: clearing the related in terrupt mask will not generate an unwanted reset concurrent interrupt context the symptom does not occur when the interrupts are handled normally, i.e. when: ? the interrupt flag is cleared within its own inter- rupt routine ? the interrupt flag is cleared within any interrupt routine ? the interrupt flag is cleared in any part of the code while this interrupt is disabled if these conditions are not met, the symptom can be avoided by implementing the following se- quence: perform sim and rim operation before and after resetting an active interrupt request. example: sim reset interrupt flag rim nested interrupt context: the symptom does not occur when the interrupts are handled normally, i.e. when: ? the interrupt flag is cleared within its own inter- rupt routine ? the interrupt flag is cleared within any interrupt routine with higher or identical priority level ? the interrupt flag is cleared in any part of the code while this interrupt is disabled if these conditions are not met, the symptom can be avoided by implementing the following se- quence: push cc sim reset interrupt flag pop cc 15.1.4 16-bit timer pwm mode in pwm mode, the first pwm pulse is missed after writing the value fffch in the oc1r register (oc1hr, oc1lr). it leads to either full or no pwm during a period, depending on the olvl1 and olvl2 settings. 15.1.5 sci wrong break duration description a single break character is sent by setting and re- setting the sbk bit in the scicr2 register. in some cases, the break ch aracter may have a long- er duration than expected: - 20 bits instead of 10 bits if m=0 - 22 bits instead of 11 bits if m=1. in the same way, as long as the sbk bit is set, break characters are sent to the tdo pin. this may lead to generate one break more than expect- ed. occurrence the occurrence of the problem is random and pro- portional to the baudrate. with a transmit frequen- cy of 19200 baud (fcpu=8mhz and sci- brr=0xc9), the wrong break duration occurrence is around 1%. workaround if this wrong duration is not compliant with the communication protocol in the application, soft- ware can request that an idle line be generated before the break character. in this case, the break duration is always correct assuming the applica- 1
st7232a 152/154 device configuration an d ordering information (cont?d) tion is not doing anything between the idle and the break. this can be ensured by temporarily disa- bling interrupts. the exact sequence is: - disable interrupts - reset and set te (idle request) - set and reset sbk (break request) - re-enable interrupts 15.1.6 39-pulse icc entry mode for flash devices, icc mo de entry using st7 ap- plication clock (39 pulses) is not supported. exter- nal clock mode must be used (36 pulses). refer to the st7 flash programming reference manual. 15.2 rom devices only 15.2.1 i/o port a and f configuration when using an external quartz crystal or ceramic resonator, a few f osc2 clock periods may be lost when the signal pattern in table 31 occurs . this is because this pattern ca uses the device to enter test mode and return to user mode after a few clock periods. user program execution and i/o status are not changed, only a few clock cycles are lost. this happens with either one of the following con- figurations: pa3=0, pf4=1, pf1=0 while pll option is disa- bled and pf0 is toggling pa3=0, pf4=1, pf1=0, pf0=1 while pll option is enabled this is detailed in the following table table 31. port a and f configuration: as a consequence, for cycle-accurate operations, these configurations are prohibited in either input or output mode. workaround: to avoid this occurring, it is recommended to con- nect one of these pins to gnd (pf4 or pf0) or v dd (pa3 or pf1). 15.2.2 external clock source with pll pll is not supported with external clock source. pll pa3 pf4 pf1 pf0 clock disturbance off010toggling max. 2 clock cy- cles lost at each rising or falling edge of pf0 on010 1 max. 1 clock cy- cle lost out of every 16 1
st7232a 153/154 16 revision history table 32. revision history date revision description of changes april-2005 1 first release. 1
st7232a 154/154 notes: information furnished is believed to be accurate and reliable. however, stmicroelectronics assumes no responsibility for the co nsequences of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. no license is granted by implication or otherwise under any patent or patent rights of stmicroelectronics. specifications mentioned in this publicati on are subject to change without notice. this publication supersedes and replaces all information previously supplied. stmicroelectronics prod ucts are not authorized for use as critical components in life support devices or systems without express written approval of stmicroelectro nics. the st logo is a registered trademark of stmicroelectronics. all other names are the property of their respective owners ? 2005 stmicroelectronics - all rights reserved stmicroelectronics group of companies australia ? belgium - brazil - canada - china ? czech republic - finland - france - germany - hong kong - india - israel - ital y - japan - malaysia - malta - morocco - singapore - spain - sweden - switzerland - united kingdom - united states of america www.st.com 1

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