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WM9704M AMC'97 Audio and Modem Codec
Production Data, January 2001, Rev 3.2
DESCRIPTION
WM9704M is a high quality audio codec compliant with the AC'97 Revision 2.1 specification. The WM9704M has a proprietary mode which can meet the requirements of an AMC'97 codec. It performs full duplex 18-bit codec functions from 8 to 48ksamples/s and offers excellent quality with high SNR. Features include 3D sound and line-level outputs. Support is also provided for variable sample rates and master/slave mode operation. In modem mode the device supports simultaneous modem and stereo playback. WM9704M is interchangeable with AC'97 Codecs from Wolfson and other suppliers in the basic Revision 2.1 mode. WM9704M is fully operable with 3.3V or 5V or mixed 3.3/5.0V supplies and is packaged in an industry standard 48-pin TQFP package.
FEATURES
* * * * * * * * * 4 DAC channels, stereo ADC S/N ratio > 95dB Variable rate audio and modem support Analogue 3D stereo enhancement Line level outputs Master/slave ID selection Low power implementation 3.3V or 5V operation 48-pin TQFP package
APPLICATIONS
* Simultaneous modem operation and stereo playback
BLOCK DIAGRAM
VOL/ MUTE VOL/ MUTE VOL/ MUTE
REV. 2.1 SWITCH
VOL/ MUTE
(35,36) LINEOUT (FRONT)
VOL/ MUTE KEY: MONO STEREO
MUX
VOL/ MUTE VOL/ MUTE
(39,41) LINEOUT (REAR) (37) MONOOUT
VOL/ MUTE
REAR STEREO DAC FRONT STEREO DAC
SRC
(40) MODE1 (30) MODE0
VOL/ MUTE
SRC
(47) EAPD
3D
VOL/ MUTE VOL/ MUTE VOL/ MUTE VOL/ MUTE VOL/ MUTE
SERIAL SERIAL I/F I/F
(6) BITCLK (10) SYNC (8) SDATAIN
VOL RECORD MUX AND MUTE
WM9704M
(5) SDATAOUT (11) RESETB
CD (18,20) LINEIN (23,24) VIDEO (16,17) AUX (14,15) PHONE (13) PCBEEP (12) MIC[1] (21) MUX MIC[2] (22)
STEREO ADC
SRC
0dB/ 20dB
MASTER/ SLAVE SELECT GENERAL IO SUPPORT
(45) CID0 (46) CID1 (43,44,48) GPIO[1:3] (2) XTLIN (3) XTLOUT
OSC
WOLFSON MICROELECTRONICS LTD
Lutton Court, Bernard Terrace, Edinburgh, EH8 9NX, UK Tel: +44 (0) 131 667 9386 Fax: +44 (0) 131 667 5176 Email: sales@wolfson.co.uk http://www.wolfson.co.uk
Production Data datasheets contain final specifications current on publication date. Supply of products conforms to Wolfson Microelectronics' Terms and Conditions.
2001 Wolfson Microelectronics Ltd.
WM9704M PIN CONFIGURATION
LNLVLOUTR MODE1 LNLVLOUTL AVDD2 MONOOUT
Production Data
ORDERING INFORMATION
DEVICE WM9704CFT/V TEMP. RANGE 0 to 70 C
o
PACKAGE 48-pin TQFP
DVDD1 XTLIN XTLOUT DVSS1 SDATAOUT BITCLK DVSS2 SDATAIN DVDD2 SYNC RESETB PCBEEP
1 2 3 4 5 6 7 8
48 47 46 45 44 43 42 41 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26
AVSS2
GPIO3
GPIO2 GPIO1
EAPD
CID1 CID0
LINEOUTR LINEOUTL CX3D2 CX3D1 CAP2 CAP1 MODE0 AFILT1 VREFOUT VREF AVSS1 AVDD1
9 10 11
25 12 13 14 15 16 17 18 19 20 21 22 23 24
ABSOLUTE MAXIMUM RATINGS
Absolute Maximum Ratings are stress ratings only. Permanent damage to the device may be caused by continuously operating at or beyond these limits. Device functional operating limits and guaranteed performance specifications are given under Electrical Characteristics at the test conditions specified ESD Sensitive Device. This device is manufactured on a CMOS process. It is therefore generically susceptible to damage from excessive static voltages. Proper ESD precautions must be taken during handling and storage of this device. As per specifications IPC/JEDEC J-STD-020A and JEDEC A113-B, this product requires specific storage conditions prior to surface mount assembly. It has been classified as having a Moisture Sensitivity Level of 2 and as such will be supplied in vacuum-sealed moisture barrier bags. CONDITION Digital supply voltage Analogue supply voltage Voltage range digital inputs Voltage range analogue inputs Operating temperature range, TA Storage temperature Package body temperature (soldering 10 seconds) Package body temperature (soldering 2 minutes) Note: 1. The digital supply voltage (DVDD) must always be less than or equal to the analogue supply voltage (AVDD). MIN -0.3V -0.3V DVSS -0.3V AVSS -0.3V 0C -65oC
o
LINEINL LINEINR
AUXL AUXR
MIC1
VIDEOL
VIDEOR CDL
PHONE
CDGND
MIC2
CDR
MAX +7V +7V DVDD +0.3V AVDD +0.3V +70oC +150oC +240oC +183oC
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WM9704M
RECOMMENDED OPERATING CONDITIONS
PARAMETER Digital supply range Analogue supply range Digital ground Analogue ground Difference DVSS to AVSS Analogue supply current Digital supply current Standby supply current (all PRs set) Analogue supply current Digital supply current Standby supply current (all PRs set) DVDD, AVDD = 5V DVDD, AVDD = 5V DVDD, AVDD = 5V DVDD, AVDD = 3.3V DVDD, AVDD = 3.3V DVDD, AVDD = 3.3V SYMBOL DVDD1, DVDD2 AVDD1, AVDD2 DVSS1, DVSS2 AVSS1, AVSS2 -0.3 TEST CONDITIONS MIN -10% -10% TYP 3.3 to 5.0 3.3 to 5.0 0 0 0 35 25 10 22 15 6 +0.3 MAX +10% +10% UNIT V V V V V mA mA A mA mA A
ELECTRICAL CHARACTERISTICS
Test Characteristics: AVDD = 5V, GND = 0V ..............TA = 0oC to +70oC, unless otherwise stated DVDD = 3.3V, GND = 0V ..............TA = 0oC to +70oC, unless otherwise stated PARAMETER Input LOW level Input HIGH level Output LOW Output HIGH Input level Output level Reference Levels Reference input/output CAP2 impedance Mixer reference MIC reference ADC reference DAC reference MIDBUFF current sink (pins CAP1, AFILT2, VREF and VREFOUT) MIDBUFF current source (pins CAP1, AFILT1, VREF and VREFOUT) MIDBUFF current source (pins CAP1, AFILT1, VREF and VREFOUT) VREF VREFOUT CAP1 AFILT1 AVDD = 5V -5 CAP2 2/5 AVDD AVDD/2 75 Buffered CAP2 Buffered CAP2 Buffered CAP2 Buffered CAP2 -15 3/5 AVDD V kohms V V V V mA SYMBOL VIL VIH VOL VOH IOL = 2mA IOH = 2mA Minimum input impedance = 10k Into 10kohm load 0.9 x DVDD AVSS -100mV AVSS +100mV AVDD +100mV AVDD -100mV TEST CONDITIONS MIN AVSS -0.3 2.0 TYP MAX 0.8 AVDD +0.3 0.1 x DVSS UNIT V V V V V V
Digital Logic Levels (DVDD = 3.3 or 5.0V)
Analogue I/O Levels (Input signals on any inputs, Outputs on LINEOUT L, R and MONO)
Near rail to rail
AVDD = 5V
5
15
mA
AVDD = 3.3V
5
mA
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WM9704M
Test Characteristics: AVDD = 5V, GND = 0V ..............TA = 0oC to +70oC, unless otherwise stated DVDD = 3.3V, GND = 0V ..............TA = 0oC to +70oC, unless otherwise stated PARAMETER SNR A-weighted (Note 1) Full scale output voltage THD Frequency response Transition band Stop band Out of band rejection Spurious tone reduction PSRR SNR A-weighted (Note 1) ADC input for full scale output THD Frequency response Transition band Stop band Stop band rejection PSRR SNR CD path A-weighted (Note 1) SNR Other paths A-weighted (Note 1) Maximum input voltage Maximum output voltage on LINEOUT THD Frequency response (+/-1dB) Input impedance (CD inputs) Input impedance (other mixer inputs) Input impedance MIC inputs PSRR SNR A-weighted (Note 1) Full scale output voltage THD Frequency response Transition band Stop band Out of band rejection Spurious tone reduction PSRR 20 to 20kHz VREF = 1.65V -3dBFSsp output 20 19,200 28,800 -40 -100 40 At any gain At max gain At 0db gain At max gain At 0db gain 20 to 20kHz 20 to 20kHz 90 85 AVSS 1.0 74 20 10 10 15 20 100 80 15 40 96 0.7 90 19,200 28,800 Mixer Circuit Specifications (AVDD = 5V) 48kHz sampling 100 95 1.0 1.8 90 20,000 AVDD VREF = 2.5V -6dBFS input 74 20 19,200 28,800 -74 40 20 to 20kHz 75 ADC Circuit Specifications (AVDD = 5V) 48kHz sampling 85 1.0 90 19,200 28,800 VREF = 2.5V -3dB output 74 20 19,200 28,800 -40 -100 40 SYMBOL TEST CONDITIONS MIN 85 TYP 96 1.0 90 19,200 28,800 MAX
Production Data
UNIT dB Vrms % Hz Hz Hz dB dB dB dB Vrms % Hz Hz Hz dB dB dB dB Vrms Vrms % Hz kohm kohm kohm kohm kohm dB dB Vrms % Hz Hz Hz dB dB dB
DAC Circuit Specifications (AVDD = 5V) 48kHz sampling
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DAC Circuit Specifications (AVDD = 3.3V) 48kHz sampling
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Production Data Test Characteristics: AVDD = 5V, GND = 0V ..............TA = 0oC to +70oC, unless otherwise stated DVDD = 3.3V, GND = 0V ..............TA = 0oC to +70oC, unless otherwise stated PARAMETER SNR A-weighted (Note 1) ADC input for full scale output THD Frequency response Transition band Stop band Stop band rejection PSRR SNR CD path A-weighted (Note 1) SNR Other paths A-weighted (Note 1) Maximum input voltage Maximum output voltage on LINEOUT THD Frequency response (+/-1dB) Input impedance (CD inputs) Input impedance (other Mixer inputs) Input impedance MIC inputs PSRR Clock Frequency Range Crystal clock BIT_CLK frequency SYNC frequency Note: 24.576 12.288 48.0 At any gain At max gain At 0db gain At max gain At 0db gain 20 to 20kHz -3dBV input 20 15 20 100 80 15 40 20 to 20kHz Mixer Circuit Specifications (AVDD = 3.3V) 48kHz sampling 97 92 0.7 0.7 90 20,000 VREF = 1.65V -9dBFS input 20 19,200 28,800 -74 40 SYMBOL TEST CONDITIONS MIN TYP 82 0.7 80 19,200 28,800 MAX
WM9704M
UNIT dB Vrms % Hz Hz Hz dB dB dB dB Vrms Vrms % Hz kohm kohm kohm kohm kohm dB MHz MHz kHz
ADC Circuit Specifications (AVDD = 3.3V) 48kHz sampling
1. SNR is the ratio of 0dB signal amplitude to noise floor with no signal, measured A-weighted over a 20Hz to 20kHz bandwidth.
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WM9704M PIN DESCRIPTION
PIN 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 Note: 1. Pins 27, 29 and 31 have an internal connection. WOLFSON MICROELECTRONICS LTD NAME DVDD1 XTLIN XTLOUT DVSS1 SDATAOUT BITCLK DVSS2 SDATAIN DVDD2 SYNC RESETB PCBEEP PHONE AUXL AUXR VIDEOL VIDEOR CDL CDGND CDR MIC1 MIC2 LINEINL LINEINR AVDD1 AVSS1 VREF(1) VREFOUT AFILT1(1) MODE0 CAP1(1) CAP2 CX3D1 CX3D2 LINEOUTL LINEOUTR MONOOUT AVDD2 LNLVLOUTL MODE1 LNLVLOUTR AVSS2 GPIO1 GPIO2 CID0 CID1 EAPD GPIO3 TYPE Supply Digital input Digital output Supply Digital input Digital output (master) Digital input (slave) Supply Digital output Supply Digital input Digital input Analogue input Analogue input Analogue input Analogue input Analogue input Analogue input Analogue input Analogue input Analogue input Analogue input Analogue input Analogue input Analogue input Supply Supply Analogue output Analogue output Analogue output Digital input Analogue output Analogue input Analogue output Analogue input Analogue output Analogue output Analogue output Supply Analogue output Digital input Analogue output Supply Programmable I/O Programmable I/O Digital input Digital input Digital output Programmable I/O DESCRIPTION Digital positive supply
Production Data
Clock crystal connection or clock input (XTAL not used) Clock crystal connection Digital ground supply Serial data input Serial interface clock output to AC'97 controller or input from AC'97 master codec Digital ground supply Serial data output to AC'97 controller Digital positive supply Serial interface sync pulse from AC'97 controller NOT reset input (active low, resets registers) Mixer input, typically for PCBEEP signal Mixer input, typically for PHONE signal Mixer input, typically for AUX signal Mixer input, typically for AUX signal Mixer input, typically for VIDEO signal Mixer input, typically for VIDEO signal Mixer input, typically for CD signal CD input common mode reference (ground) Mixer input, typically for CD signal Mixer input with extra gain if required Mixer input with extra gain if required Mixer input, typically for LINE signal Mixer input, typically for LINE signal Analogue positive supply Analogue ground supply, chip substrate Buffered CAP2 Reference for microphones; buffered CAP2 Buffered CAP2 6 channel support I2S enable Buffered CAP2 Reference input/output; pulls to midrail if not driven Output pin for 3D difference signal Input pin for 3D difference signal Main analogue output for left channel Main analogue output for right channel Main mono output Analogue positive supply Left channel line level output Mode select pin, internal pull down Right channel line level output Analogue ground supply, chip substrate GPIO or I2S GPIO or I2S Master/slave ID select (internal pull-up) Master/slave ID select (internal pull-up) External amplifier power down/GPO GPIO
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WM9704M
DETAILED TIMING DIAGRAMS
Test Characteristics: AVDD = 5V, GND = 0V ..............TA = 0oC to +70oC, unless otherwise stated DVDD = 3.3V, GND = 0V ..............TA = 0oC to +70oC, unless otherwise stated All measurements are taken at 10% to 90% VDD, unless otherwise stated.
AC-LINK LOW POWER MODE
SLOT 1 SYNC
SLOT 2
BIT_CLK
SDATA_OUT
WRITE TO 0X20
DATA PR4
DON'T CARE
tS2_PDOWN SDATA_IN
Figure 1 AC-Link Powerdown Timing PARAMETER End of slot 2 to BITCLK SDATIN low SYMBOL tS2_PDOWN MIN TYP MAX 1.0 UNIT s
COLD RESET
tRST_LOW RESETB tRST2CLK
BIT_CLK
Figure 2 Cold Reset Timing PARAMETER RESETB active low pulse width RESETB inactive to BIT_CLK startup delay SYMBOL tRST_LOW tRST2_CLK MIN 1.0 162.8 TYP MAX UNIT s ns
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WM9704M
WARM RESET
tSYNC_HIGH SYNC tSYNC2CLK
Production Data
BIT_CLK
Figure 3 Warm Reset Timing PARAMETER SYNC active high pulse width SYNC inactive to BIT_CLK startup delay SYMBOL tSYNC_HIGH tSYNC2_CLK 162.4 MIN TYP 1.3 MAX UNIT s ns
CLOCK SPECIFICATIONS
tCLK_HIGH BIT_CLK tCLK_PERIOD tSYNC_HIGH SYNC tSYNC_PERIOD tSYNC_LOW tCLK_LOW
Figure 4 Clock Specifications (50pF External Load) PARAMETER BIT_CLK frequency BIT_CLK period BIT_CLK output jitter BIT_CLK high pulse width (Note 1) BIT_CLK low pulse width (Note 1) SYNC frequency SYNC period SYNC high pulse width SYNC low pulse width tSYNC_PERIOD tSYNC_HIGH tSYNC_LOW tCLK_HIGH tCLK_LOW 32.56 32.56 40.7 40.7 48.0 20.8 1.3 19.5 tCLK_PERIOD SYMBOL MIN TYP 12.288 81.4 750 48.84 48.84 MAX UNIT MHz ns ps ns ns KHz s s s
Note: Worst case duty cycle restricted to 40/60
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WM9704M
DATA SETUP AND HOLD (50PF EXTERNAL LOAD)
tSETUP BIT_CLK tHOLD SYNC SDATA_OUT
Figure 5 Data Setup and Hold (50pF External Load) PARAMETER Setup to falling edge of BIT_CLK Hold from falling edge of BIT_CLK SYMBOL tSETUP tHOLD MIN 15.0 5.0 TYP MAX UNIT ns ns
Note: Setup and hold time parameters for SDATA_IN are with respect to AC'97 Controller.
SIGNAL RISE AND FALL TIMES
triseCLK BIT_CLK triseSYNC SYNC triseDIN SDATA_IN triseDOUT SDATA_OUT tfallDOUT tfallDIN tfallSYNC tfallCLK
Figure 6 Signal Rise and Fall Times (50pF external load) PARAMETER BIT_CLK rise time BIT_CLK fall time SYNC rise time SYNC fall time SDATA_IN rise time SDATA_IN fall time SDATA_OUT rise time SDATA_OUT fall time SYMBOL triseCLK tfallCLK triseSYNC tfallSYNC triseDIN triseDIN triseDOUT tfallDOUT MIN 4 4 4 4 4 4 4 4 TYP MAX 40 40 40 40 40 40 40 40 UNIT ns ns ns ns ns ns ns ns
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WM9704M SYSTEM INFORMATION
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MIC1 MIC2 PCBEEP
CD, VIDEO, AUX, LINEIN
22
21
12
35 LINEOUTL/R FRONT DATA 36
RESET
11 6 10 8 5 45 46 2 3 MODE0 = 1 MODE1 = 1 43 44 48 GPIO [1:3] 39, 41
AC'97 DIGITAL CONTROLLER
BITCLK SYNC SDATAIN SDATAOUT
LNLVLOUTL/R
Tx Rx
WM9704M
(MODEM MODE)
PHONE 13 37 MONOOUT
DAA
MODEM DATA
CHIP SELECT
{
CID0 CID1
XTAL
Figure 7 WM9704M in a Typical Application
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WM9704M
DEVICE DESCRIPTION
INTRODUCTION
The WM9704M comprises a stereo 18-bit Codec, (that is, 2 ADCs and 2 DACs) plus two additional DACs. The additional pair of DAC channels are used to convert the Modem Tx data mapped from the Line1 interface slot, at the sample rate selected in the Modem Rate register. Additionally, a vendor specific mode is provided to allow dual line support for line1 and line2. Alternatively, the WM9704M can be configured as a standard AC'97 Rev 2.1 device. In this mode the device includes line level outputs and support for the variable rate audio sample rates specified in Rev 2.1. The WM9704M is fully compliant with Rev 2.1 of the AC'97 specification. The WM9704M comprises a stereo 18-bit Codec, (that is, 2 ADCs and 2 DACs) plus two additional DACs. The WM9704M also has a comprehensive analogue mixer with 4 sets of stereo inputs, plus phone, 2 microphone, and PC-beep inputs. Additionally, on-chip reference circuits generate the necessary bias voltages for the device, and a bi-directional serial interface allows transfer of control data and DAC and ADC words to and from the AC'97 controller. The WM9704M supports 18-bit resolution within the DAC and ADC functions, but the AC'97 serial interface specification allows any word length up to 20-bits to be written to, or read from, the AC'97 Codec. These words are MSB justified, and any LSBs not used will simply default to 0. Normally it is anticipated that 16-bit words will be used in most PC type systems. Therefore, for the DAC, 16-bit words will be downloaded into the Codec from the controller, along with padding of 0s to make the 16-bit word up to 20-bit length. In this case, the WM9704M will process the 16-bit word along with 0 padding bits in the 2 LSB locations (to make 18-bit). At the ADC output, WM9704M will provide an 18-bit word, again with 0s in the two LSB locations (20-bit). The AC'97 controller will then ignore the 4 LSBs of the 20-bit word. When the WM9704M is interrogated, it responds indicating it is an 18-bit device. The WM9704M has the ADC and DAC functions implemented using oversampled, or `sigma-delta' converters, and uses on-chip digital filters to convert these 1-bit signals to and from the 48ks/s 16/18bit PCM words that the AC'97 controller requires. The digital parts of the device are powered separately from the analogue to optimise performance, and 3.3V digital and 5V analogue supplies may be used on the same device to further optimise performance. Digital IOs are 5V tolerant when the analogue supplies are 5V, so the WM9704M may be connected to a controller running on 5V supplies, but use 3.3V for the digital section of WM9704M. WM9704M is also capable of operating with a 3.3V supply only (digital and analogue). An internally generated midrail reference is provided at pin CAP2 which is used as the chip reference. This pin should be heavily decoupled. The WM9704M is not limited to PC-only applications. The ability to powerdown sections of the device selectively, and the option to choose alternative master clock, and hence sample rates, means that many alternative applications in areas such as telecomms, may be anticipated. Additional features added to the Intel AC'97 specification, such as the EAPD (External Amplifier Power Down) bit, internal connection of PC-beep to the outputs in the case where the device is reset, are supported, along with optional features such as variable sample rate support.
OPERATIONAL MODES
The WM9704M is pin programmable to operate in the following modes: MODE1 PIN 0 1 MODE0 PIN 0 1 OPERATIONAL MODE 2-channel Modem mode RESULTING DEVICE BEHAVIOUR Rev 2.1 compliant codec (2-channel mode) Modem DAC mode
Table 1 Operating Modes
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MODEM MODE
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In Modem mode the modem Tx data is mapped onto the rear DACs. Rear DAC sample rates are set by the Modem Tx sample rate register 40h, and extended modem capability register 3Ch indicates Line1 is supported. The following features are supported in Modem Mode: * * * * * * * Vendor ID reads back WML4 Headphone channel flagged as `not supported' (bit ID4 in register 00h) 4 channels of DAC and 2 of ADC conversion available, with all recommended Audio and Modem sample rates supported via the audio sample rate registers 2Ch (front DACs), 40h (rear DACs) and 32h (ADCs in audio mode) ADC samples are output onto both audio slots 3 & 4 and also line2/1 slots 10 & 5 respectively Line1 Tx modem data is mapped onto the rear DACs as data and inverted data, so that the PAIR of rear DACs produce a differential Tx modem data output. Right audio ADC changes to use line1 sample rate 40h, when input mix selects PHONE as its IP. Additional vendor specific mode DLM is available via bit DLM in register 5Ah. Setting this bit provides support for line2 as well as line1 slots. Rear DACs are mapped onto line1 and line2 Tx modem data slots, and ADC Left and right outputs are mapped both onto normal audio slots 3 and 4 and also onto the line1 and line2 Rx modem data slots. Modem rate register 40h is used for both DACs and the ADC's use their normal sample rate registers i.e. audio registers, unless Right channel is selected as PHONE, in which case they too use register 40h. If DLM bit is set in register 5Ah, then line1 Tx data is mapped onto the rear left DAC, and Line2 Tx data is mapped onto the rear right DAC. Both rear DACs use the same sample rate from register 40h (if 42h is written to, 40h will be updated instead) Left ADC always uses normal ADC audio rate register, except in DLM mode when RPHONE is selected, when it uses 40h GPIO capability supporting GPIO (11 to 13) is flagged as supported Master/slave ID0/1 are supported, with automatic re-mapping of the rear or LFE/center DAC slot data onto the front DACs when ID 10 or 11 are selected Headphone/line level output pins 39 and 41 are used to output the rear DAC signals, with volume controlled from register 04h. Rear mixer PGA is fixed in MUTE condition. Wolfson 3D stereo enhancement supported Master volume control register maps to the location dependant on selected ID: (ID 00 or 01 uses master volume at register 02h, ID 10 uses 38h (surround volume) and ID11 uses 36h (LFE, Center volume) In this case, bits 7 and 15 act as left and right mute.) Front DAC mute (reg18h) automatically de-muted, when ID is 1x, i.e. used as surround DAC or LFE/center, when surround or LFE/center master volume is de-muted. Rear DAC mute (reg70h) automatically de-muted when 04h volume is de-muted ADC's always used record level from register 1Ch
* * * * * * * * * *
In order to achieve the above functionality, the following changes to the Rev 2.1 compliant, or quad mode, defaults are made: * * * * Rev 2.1 legacy compliance switch is opened (can be closed using REV2SW bit in register 5Ah) Rear channel mixer PGA default is now permanently muted, (unlikely that the user wants to send the analogue mix output onto the Tx modem line output) Tx modem level at the LNLVL pins still controlled from 04h rather than 46h or 48h (which would normally be the modem ADC and DAC level control registers) Rx ADC input levels are still controlled from the normal ADC record level register 1Ch (rather than 46h or 48h due to the difficulty in re-allocating left and right channel gain controls into two different registers)
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WM9704M
REV 2.1 COMPLIANT 2-CHANNEL MODE
Features in this mode are as follows: * * * * * * Vendor ID reads back as WML3 2 channels of ADC and DAC conversion provided, with all recommended Audio and Modem sample rates supported via the audio sample rate registers 2Ch and 32h Master/slave ID0/1 are supported Headphone/line level outputs duplicating the main outputs, are supported, with gain control from register 04h Wolfson 3D stereo enhanced sound supported Master volume control register maps to the location dependant on selected ID: (ID 00 or 01 uses master volume at register 02h, ID 10 uses 38h (surround volume) and ID11 uses 36h (LFE, Centre volume)
GPIO PINS
The AC'97 Rev 2.1 specification allows for provision of programmable IO pins, up to 16 in number. Within the 48-pin TQFP package used, provision has been made for 3 pins to be used as GPIO pins. These pins (numbers 43, 44, 48) are also used as I2S output pins to support multi-channel operation. When used as GPIO pins, the pins 43, 44, 48 are mapped onto the bits 11,12,13 in the AC-link slot 12. These optional locations may be configured in any way: as inputs or outputs, supporting interrupt operation etc, offering maximum flexibility to the user. The appropriate GPIO control registers are supported to control these pins. Configuration of these pins as GPIO is described in the Control Interface description.
3D STEREO ENHANCEMENT
This device contains a `stereo enhancement' circuit, designed to optimise the listening experience when the device is used in a typical PC operating environment. That is, with a pair of speakers placed either side of the monitor with little spatial separation. This circuit creates a difference signal by differencing left and right channel playback data, then filters this difference signal using lowpass and highpass filters whose time constants are set using external capacitors connected to the CX3D pins (33 and 34). Typically the values of 100nF and 47nF set highpass and lowpass poles at about 100Hz and 1kHz respectively. This frequency band corresponds to the range over which the ear is most sensitive to directional effects. The filtered difference signal is gain adjusted by an amount set using the 4-bit value written to register 22h bits 3 to 0. Value 0h is `disable', value Fh is maximum effect. Typically a value of 8h is optimum. The user interface would most typically use a slider type of control to allow the user to adjust the level of enhancement to suit the program material. Bit D13 `3D' in register 20h is the overall 3D enable bit. The capability register 00h reads back the value 11000 in bits D14 to D10. This corresponds to decimal 24, which is registered with Intel as `Wolfson Stereo Enhancement'. Note that the external capacitors setting the filtering poles applied to the difference signal may be adjusted in value, or even replaced with a direct connection between the pins. If such adjustments are made, then the amount of difference signal fed back into the main signal paths may be significant, and can cause large signals which may limit, distort, or overdrive signal paths or speakers. Adjust these values with care, to select the preferred acoustic effect. There is no provision for pseudo-stereo effects. Mono signals will have no enhancement applied (if the signals are in phase and of the same amplitude). Signals from the PCM DAC channels do not have stereo enhancement applied. It is assumed that these signals will already have been processed digitally with any required 3D-enhancement effect. Applying the analogue 3D enhancement will corrupt this digital effect. This is equivalent to setting the POP bit in register 20h. As a result, the readback value of this bit is fixed as '1', and attempts to change it will be ignored. POP bit is set to one and cannot be re-set.
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WM9704M
VARIABLE SAMPLE RATE SUPPORT
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The DACs and ADCs on this device support all the recommended sample rates specified in the Intel Rev 2.1 specification for both audio and modem rates. Default rates are 48ks/s. If alternative rates are selected, the AC'97 interface continues to run at 48k words per second, but data is transferred across the link in bursts such that the net sample rate selected is achieved. It is up to the AC'97 Rev 2.1 compliant controller to ensure that data is supplied to the AC link, and received from the AC link, at the appropriate rate. The device supports `on demand' sampling. That is, when the DAC signal processing circuits need another sample, a sample request is sent to the controller which must respond with a data sample in the next frame it sends. For example, if a rate of 24ks/s is selected, on average the device will request a sample from the controller every other frame, for each of the stereo DACs. Note that if an unsupported rate is written to one of the rate registers, the rate will default to the nearest rate supported. The register will then respond when interrogated with the supported rate the device has defaulted to. ADCs are controlled similarly but with one difference: Normally the left and right channel ADCs sample at the same rate. AUDIO SAMPLE RATE CONTROL VALUE D15 TO D0 MODEM SAMPLE RATE 7200 8000 11025 16000 22050 44100 48000 1F40 2B11 3E80 5622 AC44 BB80 8228.57 (57600/7) 8400 9000 9600 10285.71 (72000/7) 12000 13714.28 (96000/7) 19200 24000 CONTROL VALUE D15 TO D0 1C20 2024 20D0 2328 2580 282D 2EE0 3592 4B00 5DC0
Table 2 Variable Sample Rates Supported The following table shows which registers control which DAC rates, versus Mode and ID selected MODE ID 00 and 01 10 11 00 and 01 10 11 FRONT DAC RATE REGISTER 2Ch 2Eh 2Ch (centre) and 30h (LFE) 2Ch 2Eh 2Ch (centre) and 30h (LFE) REAR DAC RATE REGISTER ADC RATE REG 32h 32h (40h if PHONE IP selected)
Rev 2.1 mode (00)
Modem mode (11)
40h
Table 3 Variable Rate Register Location Versus Mode and ID
GAIN CONTROL REGISTER LOCATION VERSUS MODE AND ID
Depending on what mode and ID the device is operated in, the various gain control registers have locations in the register map that may change. In Modem mode, the rear volume is mapped always to location 46h, and the rear mixer is fixed muted so analogue sources cannot be summed into the Tx modem signal.
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REV 2.1 MODE (00) PGA ID 0x 10 11 0x 10 11 0x 10 11 0x 10 11 0x 10 11 0x 10 11
CONTROL
MODEM MODE (11)
CONTROL
REG Front DAC PGA Rear DAC PGA Front Mixer
MUTE DEFAULT Muted (bit15) AND with 38h,7,15 AND with 36h,7,15 Muted (bit15) and powered off
REG 18h
MUTE DEFAULT Muted (bit15) AND with 38h,7,15 AND with 36h,7,15 AND with 04h, 15
18h
70h
70h
72h
Not-muted (bit15)
72h
Not-muted (bit15)
Rear Mixer
74h 02h 38h 36h 04h
Permanently muted Muted (15) muted (7 and 15) muted (7 and 15) Muted (bit15) Rev 2.1 switch enabled
74h 02h 38h 36h 04h
Permanently muted Muted (15) muted (7 and 15) muted (7 and 15) Muted (bit 15)
Front Volume Rear Volume
Table 4 Gain Control Register Location Versus Mode and ID
MASTER/SLAVE ID0/1 SUPPORT
WM9704M supports operation as either a master or a slave codec. Configuration of the device as either a master or as a slave, is selected by tying the ID pins CID0 and CID1, pins 45 and 46 on the package. Fundamentally, a device identified as a master (ID = 00) produces BITCLK as an output, whereas a slave (any other ID) must be provided with BITCLK as an input. This has the obvious implication that if the master device on an AC link is disabled, the slave devices cannot function. The AC'97 Rev 2.1 specification defines that the ID pins have inverting sense, and are provided with internal weak pull ups. Therefore, if no connections are made to the CID0/1 pins, then the pins pull `hi' and an ID = 00 is selected, i.e. `master'. External connects to ground will select other IDs. PIN46 CID1 NC NC Ground Ground Table 5 ID Selection WM9704M supports the AMAP function whereby selection of an ID will automatically map the data from the interface onto the PCM DACs. AC-LINK FRAME DATA USED FOR DACS PCM left DAC uses data from slot # 3 3 PCM right DAC uses data from slot # 4 4 PIN45 CID0 NC Ground NC Ground ID SELECTED 00 01 10 11 MASTER OR SLAVE Master Slave Slave Slave BITCLK Output Input Input Input
CODEC ID 00 01
COMMENTS
Original definition (master) Original definition (docking)
The codec ID is available to the controller via registers 28h and 3c, bits D15 and D14 Table 6 Default Slot to DAC Mappings Based on Codec ID
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MODE Rev 2.1 (00) ID 00 or 01 10 11 00 or 01 10 11 SLOTS MAPPED TO FRONT DACS 3 and 4 7 and 8 6 and 9 3 and 4 7 and 8 6 and 9
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SLOTS MAPPED TO REAR DACS Not supported in this mode 5 (or 5 & 10 if DLM set)
Modem (11)
Table 7 Slot to DAC Mapping Based on Mode and Codec ID
SLAVE CODEC REGISTER ACCESS DEFINITIONS
Master Codec access is exactly as defined for AC'97. For slave Codec access, the AC'97 Digital Controller must invalidate the tag bits for Slot 1 and 2 Command Address and Data (Slot 0, bits 14 and 13) and place a non-zero value (01, 10, or 11) into the Codec ID field (Slot 0, bits 1 and 0). Slave Codecs disregard the Command Address and Command Data (Slot 0, bits 14 and 13) tag bits when they see a 2-bit Codec ID value (Slot 0, bits 1 and 0) that matches their configuration. In a sense the Slave Codec ID field functions as an alternative Valid Command Address (for Slave reads and writes) and Command Data (for Slave writes) tag indicator. Slave Codecs must monitor the Frame Valid bit, and ignore the frame (regardless of the state of the Slave Codec ID bits) if it is not valid. AC'97 Digital Controllers should set the frame valid bit for a frame with a slave register access, even if no other bits in the output tag slot except the Slave Codec ID bits are set. OUTPUT TAG SLOT (16-BITS) BIT 15 14 13 12-3 2 1-0 DESCRIPTION Frame Valid Slot 1 Valid Command Address Bit (Master Codec only) Slot 2 Valid Command Data Bit (Master Codec only) Slot 3-12 Valid Bits as defined by AC'97 Reserved (Set to 0) 2-bit Codec ID field (00 reserved for Master; 01, 10, 11 indicate Slave)
New definitions for Slave Codec Register Access Table 8 Slave Codec Register Access Slot 0-Bit Definitions
CONTROL INTERFACE
A digital interface has been provided to control the WM9704M and transfer data to and from it. This serial interface is compatible with the Intel AC'97 specification as illustrated in the System Diagram (Figure 7). The main control interface functions are: * * * Control of analogue gain and signal paths through the mixer Bi-directional transfer of ADC and DAC words to and from AC'97 controller Selection of powerdown modes
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The WM9704M incorporates a 5-pin digital serial interface that links it to the AC'97 controller. AC-link is a bi-directional, fixed rate, serial PCM digital stream. It handles multiple input and output audio streams, as well as control register accesses employing a time division multiplexed (TDM) scheme. The AC-link architecture divides each audio frame into 12 outgoing and 12 incoming data streams, each with 20-bit sample resolution. With a minimum required DAC and ADC resolution of 16-bits, AC'97 may also be implemented with 18 or 20-bit DAC/ADC resolution, given the headroom that the AC-link architecture provides. The WM9704M provides support for 18-bit operation.
AC-LINK DIGITAL SERIAL INTERFACE PROTOCOL
SLOT NUMBER
0
1
2
3
4
5
6
7
8
9
10
11
12
SYNC
SDATA_OUT
TAG CODEC ID
CMD ADR
CMD DATA
PCM LEFT
PCM RIGHT
LINE 1 DAC
PCM CENTRE
PCM L SURR
PCM R SURR
PCM LFE
LINE 2 DAC PCM L (n+1)
HSET DAC PCM R (n+1) HSET ADC
IO CTRL PCM C (n+1) IO STATUS
SDATA_IN
TAG
STATUS ADDR
STATUS DATA
PCM LEFT
PCM RIGHT
LINE 1 ADC
MIC ADC
RSRVD
RSRVD
RSRVD
LINE 2 ADC
SLOTREQ 3-12
Figure 8 AC'97 Standard Bi-directional Audio Frame
TAG PHASE
DATA PHASE 20.8S (48kHz)
SYNC
12.288MHz 81.4nS
BIT_CLK
SDATA_OUT
VALID FRAME
SLOT(1)
SLOT(2)
SLOT(12)
'0'
(ID1)
(ID0)
19 SLOT (1)
0
19 SLOT (2)
0
19 SLOT (3)
0
19 SLOT (12)
0
END OF PREVIOUS AUDIO FRAME
TIME SLOT 'VALID' BITS ('1' = TIME SLOT CONTAINS VALID PCM DATA)
Figure 9 AC-link Audio Output Frame
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The datastreams currently defined by the AC'97 specification include: PCM playback - 2 output slots PCM record data - 2 input slots Control - 2 output slots Status - 2 input slots Optional modem line codec output 1 output slot Optional modem line codec input 1 input slot Optional dedicated microphone input 1 input slot
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2-channel composite PCM output stream 2-channel composite PCM input stream Control register write port Control register read port Modem line codec DAC input stream Modem line codec ADC output stream Dedicated microphone input stream in support of stereo AEC and/or other voice applications.
Synchronisation of all AC-link data transactions is signalled by the WM9704M controller. The WM9704M drives the serial bit clock onto AC-link, which the AC'97 controller then qualifies with a synchronisation signal to construct audio frames. SYNC, fixed at 48kHz, is derived by dividing down the serial clock (BIT_CLK). BIT_CLK, fixed at 12.288MHz, provides the necessary clocking granularity to support 12, 20-bit outgoing and incoming time slots. AC-link serial data is transitioned on each rising edge of BIT_CLK. The receiver of AC-link data, (WM9704M for outgoing data and AC'97 controller for incoming data), samples each serial bit on the falling edges of BIT_CLK. The AC-link protocol provides for a special 16-bit time slot (slot 0) wherein each bit conveys a valid tag for its corresponding time slot within the current audio frame. A "1" in a given bit position of slot 0 indicates that the corresponding time slot within the current audio frame has been assigned to a data stream, and contains valid data. If a slot is "tagged" invalid, it is the responsibility of the source of the data, (the WM9704M for the input stream, AC'97 controller for the output stream), to stuff all bit positions with 0s during that slot's active time. SYNC remains high for a total duration of 16 BIT_CLKs at the beginning of each audio frame. The portion of the audio frame where SYNC is high is defined as the "Tag Phase". The remainder of the audio frame where SYNC is low is defined as the "Data Phase". Additionally, for power savings, all clock, sync, and data signals can be halted. This requires that the WM9704M be implemented as a static design to allow its register contents to remain intact when entering a power savings mode.
AC-LINK AUDIO OUTPUT FRAME (SDATA_OUT)
The audio output frame data streams correspond to the multiplexed bundles of all digital output data targeting the WM9704M's DAC inputs, and control registers. As briefly mentioned earlier, each audio output frame supports up to 12 20-bit outgoing data time slots. Slot 0 is a special reserved time slot containing 16-bits, which are used for AC-link protocol infrastructure.
OUTPUT TAG SLOT (16-BITS)
Bit (15) Bit (14) Bit (13) Bit (12:3) Bit 2 Bit (1:0) Frame Valid Slot 1 Valid Command Address bit Slot 2 Valid Command Data bit Slot 3-12 Valid bits as defined by AC'97 Reserved 2-bit Codec ID field (Set to 0) (00 reserved for Primary; 01, 10, 11 indicate Secondary) (Primary Codec only) (Primary Codec only)
New definitions for Secondary Codec Register Access Within slot 0 the first bit is a global bit (SDATA_OUT slot 0, bit 15) which flags the validity for the entire audio frame. If the "Valid Frame" bit is a 1, this indicates that the current audio frame contains at least one time slot of valid data. The next 12-bit positions sampled by the WM9704M indicate which of the corresponding 12 time slots contain valid data.
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In this way data streams of differing sample rates can be transmitted across AC-link at its fixed 48kHz audio frame rate. Figure 9 illustrates the time slot based AC-link protocol.
WM9704M SAMPLES SYNC ASSERTION HERE
SYNC
WM9704M SAMPLES FIRST SDATA_OUT BIT OF FRAME HERE
BIT_CLK
SDATA_OUT
VALID FRAME
SLOT (1)
SLOT (2)
END OF PREVIOUS AUDIO FRAME
Figure 10 Start of an Audio Output Frame A new audio output frame begins with a low to high transition of SYNC as shown in Figure 10. SYNC is synchronous to the rising edge of BIT_CLK. On the immediately following falling edge of BIT_CLK, the WM9704M samples the assertion of SYNC. This falling edge marks the time when both sides of AC-link are aware of the start of a new audio frame. On the next rising edge of BIT_CLK, AC'97 transitions SDATA_OUT into the first bit position of slot 0 ("Valid Frame" bit). Each new bit position is presented to AC-link on a rising edge of BIT_CLK, and subsequently sampled by the WM9704M on the following falling edge of BIT_CLK. This sequence ensures that data transitions and subsequent sample points for both incoming and outgoing data streams are time aligned. Baseline AC'97 specified audio functionality MUST ALWAYS sample rate convert to and from a fixed 48ks/s on the AC'97 controller. This requirement is necessary to ensure that interoperability between the AC'97 controller and the WM9704M, among other things, can be guaranteed by definition for baseline specified AC'97 features. SDATA_OUT's composite stream is MSB justified (MSB first) with all non-valid slot bit positions stuffed with 0s by the AC'97 controller. In the event that there are less than 20 valid bits within an assigned and valid time slot, the AC'97 controller always stuffs all trailing non-valid bit positions of the 20-bit slot with 0s. As an example, consider an 8-bit sample stream that is being played out to one of the WM9704M's DACs. The first 8 bit positions are presented to the DAC (MSB justified) followed by the next 12 bit positions, which are stuffed with 0s by the AC'97 controller. This ensures that regardless of the resolution of the implemented DAC (16, 18 or 20-bit), no DC biasing will be introduced by the least significant bits. When mono audio sample streams are output from the AC'97 controller, it is necessary that BOTH left and right sample stream time slots be filled with the same data.
SLOT 1: COMMAND ADDRESS PORT
The command port is used to control features, and monitor status (see Figure 12) for the WM9704M functions including, but not limited to, mixer settings, and power management (refer to the register section). The control interface architecture supports up to 64, 16-bit read/write registers, addressable on even byte boundaries. Only the even registers (00h, 02h, etc.) are valid, odd register (01h, 03h, etc.) accesses are discouraged (if supported they should default to the preceding even byte boundary - i.e. a read to 01h will return the 16-bit contents of 00h). The WM9704M's control register file is nonetheless readable as well as writeable to provide more robust testability. Audio output frame slot 1 communicates control register address, and read/write command information to the WM9704M.
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COMMAND ADDRESS PORT BIT ASSIGNMENTS
Bit (19) Bit (18:12) Bit (11:0) Read/write command (1 = read, 0 = write)
Production Data
Control register index (64 16-bit locations, addressed on even byte boundaries) Reserved (stuffed with 0s)
The first bit (MSB) sampled by the WM9704M indicates whether the current control transaction is a read or write operation. The following 7 bit positions communicate the targeted control register address. The trailing 12 bit positions within the slot are reserved and must be stuffed with 0s by the AC'97 controller.
SLOT 2: COMMAND DATA PORT
The command data port is used to deliver 16-bit control register write data in the event that the current command port operation is a write cycle. (As indicated by slot 1, bit 19). Bit (19:4) Bit (3:0) Control register write data (stuffed with 0s if current operation is a read) Reserved (stuffed with 0s)
If the current command port operation is a read then the entire time slot must be stuffed with 0s by the AC'97 controller.
SLOT 3: PCM PLAYBACK LEFT CHANNEL
Audio output frame slot 3 is the composite digital audio left playback stream. In a typical `Games Compatible' PC this slot is composed of standard PCM (.wav) output samples digitally mixed (on the AC'97 controller or host processor) with music synthesis output samples. If a sample stream of resolution less than 20-bits is transferred, the AC'97 controller must stuff all trailing non-valid bit positions within this time slot with 0s.
SLOT 4: PCM PLAYBACK RIGHT CHANNEL
Audio output frame slot 4 is the composite digital audio right playback stream. In a typical `Games Compatible' PC this slot is composed of standard PCM (.wav) output samples digitally mixed (on the AC'97 controller or host processor) with music synthesis output samples. If a sample stream of resolution less than 20-bits is transferred, the AC'97 controller must stuff all trailing non-valid bit positions within this time slot with 0s.
SLOT 5: OPTIONAL MODEM LINE 1 CODEC
Audio output frame slot 5 contains the MSB justified modem line1 DAC input data. This optional AC'97 feature is supported in WM9704M, but only in the modem operation mode (selected with the mode0/1 pins). If data is written to this location it is applied to the rear channel DACs if the modem mode is enabled. This may be determined by the AC'97 controller interrogating the WM9704M Vendor ID registers; if modem mode is disabled, the device appears not to support modem. If the mode is enabled, the modem support flag is set.
SLOTS 6 TO 9: SURROUND SOUND DATA
Audio output frame slots 6 to 9 are used to send surround sound data to extra DAC channels. These slots are supported by WM9704M in Revision 2.1 and modem modes. Note that the data in the surround sound slots will only be applied to the front DAC. The slots used depend on the Codec ID configuration (see Table 7).
SLOT 10: OPTIONAL MODEM LINE2 CODEC
Audio output frame slot 10 contains MSB justified modem Line2 DAC input data. This optional AC'97 feature is supported by WM9704M, but only when register 5Ah DLM (Dual line modem) is set.
SLOT 11: HANDSET DAC
Slot 11 is not supported.
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SLOT 12 : GPIO CONTROL
Data in this slot is applied to the GPIO pins, if they have been enabled via the control registers. Note that only bits 11, 12 and 13 are supported, all others are ignored.
AC-LINK AUDIO INPUT FRAME (SDATA_IN)
TAG PHASE DATA PHASE 20.8S (48kHz) SYNC
12.288MHz 81.4nS
BIT_CLK
SDATA_IN
CODEC READY
SLOT(1)
SLOT(2)
SLOT(12)
'0'
'0'
'0'
19 SLOT (1)
0
19 SLOT (2)
0
19 SLOT (3)
0
19 SLOT (12)
0
END OF PREVIOUS AUDIO FRAME
TIME SLOT 'VALID' BITS ('1' = TIME SLOT CONTAINS VALID PCM DATA)
Figure 11 AC-link Audio Input Frame The audio input frame data streams correspond to the multiplexed bundles of all digital input data targeting the AC'97 controller. As is the case for audio output frame, each AC-link audio input frame consists of 12, 20-bit time slots. Slot 0 is a special reserved time slot containing 16-bits, which are used for AC-link protocol infrastructure. Within slot 0 the first bit is a global bit (SDATA_IN slot 0, bit 15) which flags whether the WM9704M is in the "Codec Ready" state or not. If the "Codec Ready" bit is a 0, this indicates that the WM9704M is not ready for normal operation. This condition is normal following the desertion of power on reset for example, while the WM9704M's voltage references settle. When the AC-link "Codec Ready" indicator bit is a 1, it indicates that the AC-link and the WM9704M control and status registers are in a fully operational state. The AC'97 controller must further probe the Powerdown Control/Status Register to determine exactly which subsections, if any, are ready. Prior to any attempts at putting the WM9704M into operation the AC'97 controller should poll the first bit in the audio input frame (SDATA_IN slot 0, bit 15) for an indication that the WM9704M has gone "Codec Ready". Once the WM9704M is sampled "Codec Ready" then the next 12 bit positions sampled by the AC'97 controller indicate which of the corresponding 12 time slots are assigned to input data streams, and that they contain valid data. Figure 11 illustrates the time slot based AC-link protocol. There are several subsections within the WM9704M that can independently go busy/ready. It is the responsibility of the WM9704M controller to probe more deeply into the WM9704M register file to determine which the WM9704M subsections are actually ready.
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WM9704M SAMPLES SYNC ASSERTION HERE
Production Data
SYNC
AC'97 CONTROLLER SAMPLES FIRST SDATA_IN BIT OF FRAME HERE
BIT_CLK
SDATA_IN
CODEC READY
SLOT (1)
SLOT (2)
END OF PREVIOUS AUDIO FRAME
Figure 12 Start of an Audio Input Frame A new audio input frame begins with a low to high transition of SYNC as shown in Figure 12. SYNC is synchronous to the rising edge of BIT_CLK. On the immediately following falling edge of BIT_CLK, AC'97 samples the assertion of SYNC. This falling edge marks the time when both sides of AC-link are aware of the start of a new audio frame. On the next rising of BIT_CLK, AC'97 transitions SDATA_IN into the first bit position of slot 0 ("Codec Ready" bit). Each new bit position is presented to AC-link on a rising edge of BIT_CLK, and subsequently sampled by the AC'97 Controller on the following falling edge of BIT_CLK. This sequence ensures that data transitions and subsequent sample points for both incoming and outgoing data streams are time aligned. SDATA_IN's composite stream is MSB justified (MSB first) with all non-valid bit positions (for assigned and/or unassigned time slots) stuffed with 0s by the WM9704M. SDATA_IN should be sampled on the falling edges of BIT_CLK.
SLOT 1: STATUS ADDRESS PORT
The status port is used to monitor status for the WM9704M functions including, but not limited to, mixer settings, and power management. Audio input frame slot 1 echoes the control register index, for historical reference, for the data to be returned in slot 2. (Assuming that slots 1 and 2 had been tagged "valid" by the WM9704M during slot 0).
STATUS ADDRESS PORT BIT ASSIGNMENTS:
Bit (19) Bit (18:12) Bit (11:2) Bit (1:0) RESERVED (stuffed with 0s) Control register index (echo of register index for which data is being returned) Variable sample rate SLOTREQ bits. RESERVED (stuffed with 0s)
The first bit (MSB) generated by the WM9704M is always stuffed with a 0. The following 7 bit positions communicate the associated control register address. The next 10 bits support the AC'97 Rev 2.1 variable sample rate signalling protocol, and the trailing 2 bit positions are stuffed with 0s by AC'97.
SLOT 2: STATUS DATA PORT
The status data port delivers 16-bit control register read data. Bit (19:4) Bit (3:0) Control register read data (stuffed with 0s if tagged "invalid" by WM9704M) RESERVED (stuffed with 0s)
If slot 2 is tagged "invalid" by the WM9704M, then the entire slot will be stuffed with 0s by the WM9704M.
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SLOT 3: PCM RECORD LEFT CHANNEL
Audio input frame slot 3 is the left channel output of the WM9704M's input Mux, post-ADC. The WM9704M's ADCs can be implemented to support 16, 18, or 20-bit resolution. The WM9704M ships out its ADC output data (MSB first), and stuffs any trailing non-valid bit positions with 0s to fill out its 20-bit time slot.
SLOT 4: PCM RECORD RIGHT CHANNEL
Audio input frame slot 4 is the right channel output of the WM9704M's input Mux, post-ADC. The WM9704M's ADCs can be implemented to support 16, 18, or 20-bit resolution. The WM9704M ships out its ADC output data (MSB first), and stuffs any trailing non-valid bit positions with 0s to fill out its 20-bit time slot.
SLOT 5: OPTIONAL MODEM LINE 1 CODEC
Audio input frame slot 5 contains MSB justified, modem ADC output data. When the device is in Modem Mode (11), then right channel ADC data is output into this slot as well as onto the normal PCM right channel slot.
SLOT 10: OPTIONAL MODEM LINE 2 CODEC
Audio input frame slot 10 contains MSB justified, modem ADC output data. When the device is in Modem Mode (11), then left channel ADC data is output into this slot as well as onto the normal PCM left channel slot.
SLOT 6: OPTIONAL DEDICATED MICROPHONE RECORD DATA
Audio input frame slot 6 is an optional (post-ADC) third PCM system, input channel available for dedicated use by a desktop microphone. This optional AC'97 feature is not supported by the WM9704M. This may be determined by the AC'97 controller interrogating the WM9704M Vendor ID register.
SLOTS 7 TO 11: RESERVED
Audio input frame slots 7 to 12 are reserved for future use and are always stuffed with 0s by AC `97. Slot 10 is filled with left ADC data in modem mode.
SLOT 12:
GPIO functions supported
AC-LINK LOW POWER MODE
The AC-link signals can be placed in a low power mode. When the WM9704M's Powerdown Register (26h), is programmed to the appropriate value, both BIT_CLK and SDATA_IN will be brought to, and held at a logic low voltage level. BIT_CLK and SDATA_IN are transitioned low immediately following the decode of the write to the Powerdown Register (26h) with PR4. When the AC'97 controller driver is at the point where it is ready to program the AC-link into its low power mode, slots 1 and 2 are assumed to be the only valid stream in the audio output frame. At this point in time it is assumed that all sources of audio input have also been neutralised. The AC'97 controller should also drive SYNC and SDATA_OUT low after programming the WM9704M to this low power, "halted" mode. Once the WM9704M has been instructed to halt BIT_CLK, a special "wake up" protocol must be used to bring the AC-link to the active mode since normal audio output and input frames can not be communicated in the absence of BIT_CLK.
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WAKING UP THE AC-LINK
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There are 2 methods for bringing the AC-link out of a low power, halted mode. Regardless of the method, it is the AC'97 controller that performs the wake up task. AC-link protocol provides for a "Cold WM9704M Reset", and a "Warm WM9704M Reset". The current powerdown state would ultimately dictate which form of WM9704M reset is appropriate. Unless a "cold" or "register" reset (a write to the Reset register) is performed, wherein the WM9704M registers are initialised to their default values, registers are required to keep state during all powerdown modes. Once powered down, re-activation of the AC-link via re-assertion of the SYNC signal must not occur for a minimum of 4 audio frame times following the frame in which the powerdown was triggered. When AC-link powers up it indicates readiness via the Codec Ready bit (input slot 0, bit 15).
COLD WM9704M RESET
A cold reset is achieved by asserting RESETB for the minimum specified time. By driving RESETB low, BIT_CLK, and SDATA_OUT will be activated, or re-activated as the case may be, and all the WM9704M control registers will be initialised to their default power on reset values. RESETB is an asynchronous WM9704M input.
WARM WM9704M RESET
A warm WM9704M reset will re-activate the AC-link without altering the current WM9704M register values. A warm reset is signalled by driving SYNC high for a minimum of 1s in the absence of BIT_CLK. Within normal audio frames SYNC is a synchronous input. In the absence of BIT_CLK, SYNC is treated as an asynchronous input used in the generation of a warm reset to the WM9704M. The WM9704M will not respond with the activation of BIT_CLK until SYNC has been sampled low again by the WM9704M. This will preclude the false detection of a new audio frame.
SERIAL INTERFACE REGISTER MAP DESCRIPTION
(See Table 22) The serial interface bits perform control functions described as follows: Note that the register map is fully specified by the AC'97 specification, and this description is simply repeated below, with optional unsupported features omitted.
RESET REGISTER (INDEX 00H)
Writing any value to this register performs a register reset, which causes all registers to revert to their default values. Reading this register returns the ID code of the part, indication of modem support (not supported by the WM9704M) and a code for the type of 3D stereo enhancement. BIT ID0 ID1 ID2 ID3 ID4 ID5 ID6 ID7 ID8 ID9 SE4...SE0 FUNCTION Dedicated Mic PCM in channel Modem line codec support Bass and treble control Simulated stereo (mono to stereo) Headphone out support Loudness (bass boost) support 18-bit DAC resolution 20-bit DAC resolution 18-bit ADC resolution 20-bit ADC resolution 3D stereo enhancement technique VALUE ON WM9704M 0 0 0 0 0 0 1 0 1 0 11000
Table 9 Reset Register Function
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Note that the WM9704M defaults to indicate 18-bit compatibility. However, a control bit may be set in the vendor-specific registers that changes bits ID6 and ID8 to be `0', indicating a 16-bit device. It is unlikely that this function will be required, however, as the MSB justification of the ADC and DAC data means that a nominally 18-bit device should be fully compatible with controllers that only provide 16-bit support. Most PC type applications will only require 16-bit operation.
PLAY MASTER VOLUME REGISTERS (INDEX 02H, 04H AND 06H)
These registers manage the output signal volumes. Register 02h controls the stereo master volume (both right and left channels), Register 04h controls the optional stereo headphone out, and Register 06h controls the mono volume output. Each step corresponds to 1.5dB. The MSB of the register is the mute bit. When this bit is set to 1 the level for that channel is set at -dB. ML5 through ML0 is for left channel level, ML5 through ML0 is for the right channel and MM5 through MM0 is for the mono out channel. Support for the MSB of the volume level is not provided by the WM9704M. If the MSB is written to, then the WM9704M detects when that bit is set and sets all 4 LSBs to 1s. Example: If the driver writes a 1xxxxx the WM9704M interprets that as x11111. It will also respond when read with x11111 rather than 1xxxxx, the value written to it. The driver can use this feature to detect if support for the 6th bit is there or not. The default value of both the mono and the stereo registers is 8000h (1000 0000 0000 0000), which corresponds to 0dB gain with mute on. MUTE 0 0 0 1 MX4...MX0 0 0000 0 0001 1 1111 x xxxx FUNCTION 0dB attenuation 1.5dB attenuation 46.5dB attenuation
dB attenuation
Table 10 Volume Register Function
MASTER TONE CONTROL REGISTERS (INDEX 08H)
Optional register for support of tone controls (bass and treble). The WM9704M does not support bass and treble and writing to this register will have no effect, reading will result in all don't care values.
PC BEEP REGISTER (INDEX 0AH)
This controls the level for the PC-beep input. Each step corresponds to approximately 3dB of attenuation. The MSB of the register is the mute bit. When this bit is set to 1 the level for that channel is set at -dB. WM9704M defaults to the PC-beep path being muted, except during reset when the path is open, so an external speaker should be provided within the PC to alert the user to power on self-test problems. MUTE 0 0 1 PV3...PV0 0000 1111 xxxx FUNCTION 0dB attenuation 45dB attenuation
dB attenuation
Table 11 PC-beep Register Function
ANALOGUE MIXER INPUT GAIN REGISTERS (INDEX 0CH - 18H)
This controls the gain/attenuation for each of the analogue inputs. Each step corresponds to approximately 1.5dB. The MSB of the register is the mute bit. When this bit is set to 1 the level for that channel is set at -dB. (See Table 12).
REGISTER 0EH (MIC VOLUME REGISTER)
This has an extra bit that is for a 20dB boost. When bit 6 is set to 1 the 20dB boost is on. The default value is 8008, which corresponds to 0dB gain with mute on. The default value for the mono registers is 8008h, which corresponds to 0dB gain with mute on. The default value for stereo registers is 8808h, which corresponds to 0dB gain with mute on.
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MUTE 0 0 0 1 GX4...GX0 00000 01000 11111 xxxxx FUNCTION +12dB gain 0dB gain -34.5dB gain -dB gain
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Table 12 Mixer Gain Control Register Function
RECORD SELECT CONTROL REGISTER (INDEX 1AH)
Used to select the record source independently for right and left (see Table 13). The default value is 0000h, which corresponds to Mic in.
SR2 TO SR0 0 1 2 3 4 5 6 7
RIGHT RECORD SOURCE Mic CD in (R) Video in (R) Aux in (R) Line in (R) Stereo mix (R) Mono mix Phone
SL2 TO SL0 0 1 2 3 4 5 6 7
LEFT RECORD SOURCE Mic CD in (L) Video in (L) Aux in (L) Line in (L) Stereo mix (L) Mono mix Phone
Table 13 Record Select Register Function
RECORD GAIN REGISTERS (INDEX 1CH AND 1EH)
1Ch is for the stereo input and 1Eh is for the optional special purpose correlated audio Mic channel. Each step corresponds to 1.5dB. 22.5dB corresponds to 0F0Fh and 000Fh respectively. The MSB of the register is the mute bit. When this bit is set to 1, the level for that channel(s) is set at -dB. The default value is 8000h, which corresponds to 0dB gain with mute on. MUTE 0 0 1 GX3...GX0 1111 0000 xxxxx FUNCTION +22.5dB gain 0dB gain -dB gain
Table 14 Record Gain Register Function
GENERAL PURPOSE REGISTER (INDEX 20H)
This register is used to control several miscellaneous functions of the WM9704M. Below is a summary of each bit and its function. Only the MIX, MS and LPBK bits are supported by the WM9704M. The MS bit controls the Mic selector. The LPBK bit enables loopback of the ADC output to the DAC input without involving the AC-link, allowing for full system performance measurements. The function default value is 8000h, which is all off. BIT POP ST 3D LD LLBK RLBK MIX MS LPBK FUNCTION PCM out path and mute, 0 = pre-3D, 1 = post-3D Simulated stereo enhancement, on/off 1 = on 3D stereo enhancement on/off, 1 = on Loudness (bass boost) on/off, 1 = on Local loop back - for modem, line codec Remote loop back - for modem, line codec Mono output select 0 = Mix, 1 = Mic Mic select 0 = Mic1, 1 = Mic2 ADC/DAC loopback mode WM9704M SUPPORT Yes, but fixed at `1' No Yes No No No Yes Yes Yes
Table 15 General Purpose Register Function WOLFSON MICROELECTRONICS LTD
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3D CONTROL REGISTER (INDEX 22H)
This register is used to control the centre and/or depth of the 3D stereo enhancement function built into of the AC `97 component. Only the depth bits DP0 to 3 have effect in the WM9704M. DP3...DP0 0 1 8 15 DEPTH 0%
Typical value 100%
RESERVED REGISTER (INDEX 24H)
This register was originally specified to control what sample rate AC'97 is sending or receiving samples for the optional modem in and out. Not supported by the WM9704M.
POWERDOWN CONTROL/STATUS REGISTER (INDEX 26H)
This read/write register is used to program powerdown states and monitor subsystem readiness. The lower half of this register is read only status, a 1 indicating that the subsection is "ready". Ready is defined as the subsection able to perform in its nominal state. When this register is written the bit values that come in on AC-link will have no effect on read only bits 0 to 7. When the AC-link "Codec Ready" indicator bit (SDATA_IN slot 0, bit 15) is a 1 it indicates that the AC-link and the WM9704M control and status registers are in a fully operational state. The AC'97 controller must further probe this Powerdown Control/Status Register to determine exactly which subsections, if any, are ready. READ BIT REF ANL DAC ADC FUNCTION VREFs up to nominal level Analogue mixers, etc ready DAC section ready to accept data ADC section ready to transmit data
Table 16 Powerdown Status Register Function The powerdown modes are as follows. The first three bits are to be used individually rather than in combination with each other. The last bit PR3 can be used in combination with PR2 or by itself. PR0 and PR1 control the PCM ADCs and DACs only. PR6 is not supported by the WM9704M. WRITE BIT PR0 PR1 PR2 PR3 PR4 PR5 PR6 EAPD FUNCTION PCM in ADCs and input Mux powerdown PCM out DACs powerdown Analogue mixer powerdown (VREF still on) Analogue mixer powerdown (VREF off) Digital interface (AC-link) powerdown (external clock off) Internal clock disable HP amp powerdown - not supported External amplifier powerdown
Table 17 Powerdown Control Register Function
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PR0 = 1 PR1 = 1 PR2 = 1 PR4 = 1
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NORMAL
ADCs OFF PR0
DACs OFF PR1
ANALOGUE OFF PR2 OR PR3
DIGITAL I/F OFF PR4
SHUT OFF CODA LINK
PR0 = 0 AND ADC = 1
PR1 = 0 AND DAC = 1
PR2 = 0 AND ANL = 1
WARM RESET
READY = 1 DEFAULT
COLD RESET
Figure 13 An Example of the WM9704M Powerdown/Powerup Flow Figure 13 illustrates one example procedure to do a complete powerdown of the WM9704M. From normal operation sequential writes to the Powerdown Register are performed to powerdown the WM9704M a piece at a time. After everything has been shut off (PR0 to PR3 set), a final write (of PR4) can be executed to shut down the WM9704M's digital interface (AC-link). The part will remain in sleep mode with all its registers holding their static values. To wake up the WM9704M, the AC'97 controller will send a pulse on the sync line issuing a warm reset. This will restart the WM9704M's digital interface (resetting PR4 to 0). The WM9704M can also be woken up with a cold reset. A cold reset will cause a loss of values of the registers, as a cold reset will set them to their default states. When a section is powered back on, the Powerdown Control/Status register (index 26h) should be read to verify that the section is ready (i.e. stable) before attempting any operation that requires it. Alternatively if RESETB is held low, all PR bits are held set so the device is held powered off until RESETB is taken high again.
PR1 = 1
PR2 = 1
PR4 = 1
ADCs OFF PR0
DACs OFF PR1
ANALOGUE OFF PR2 OR PR3
DIGITAL I/F OFF PR4
SHUT OFF CODA LINK
PR1 = 0 AND DAC = 1
PR2 = 0 AND ANL = 1
WARM RESET
Figure 14 The WM9704M Powerdown/Flow with Analogue Still Alive Figure 14 illustrates a state when all the mixers should work with the static volume settings that are contained in their associated registers. This is used when the user could be playing a CD (or external LINE_IN source) through WM9704M to the speakers but have most of the system in low power mode. The procedure for this follows the previous except that the analogue mixer is never shut down.
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POWERDOWN CONTROL/STATUS REGISTER (INDEX 26H)
Note that in order to go into ultimate low power mode, PR5 is required to be set which turns off the oscillator circuit. Asserting SYNC resets the PR5 bit and re-starts the oscillator in the same was as the AC link is restarted. Also when RESETB pin is asserted low, all PR bits are over-ridden and the entire device is powered off to ultra low power state for as long as RESETB = low. On releasing RESETB, the device is reset (all active) and powered up.
REV 2.1 REGISTERS (INDEX 28H T0 58H)
These registers are specified as to use in Rev 2.1 of the AC'97 specification and have the following functions on the WM9704M:
REGISTER 28H - EXTENDED AUDIO ID
The Extended Audio ID register is a read only register that identifies which extended audio features are supported (in addition to the original AC'97 features identified by reading the reset register at index 00h). A non-zero value indicates the feature is supported. DATA BIT VRA DRA VRM CDAC SDAC LDAC AMAP ID1 ID0 FUNCTION Variable rate audio support Double rate audio support Variable rate Mic ADC support Centre DAC support Surround DAC support LFE DAC support Slot to front DAC mapping support Codec configuration - pin 45 value Codec configuration - pin 46 value VALUE 1 0 0 0 0 (unless I2S = 1) 0 (unless I2S = 1) 1 Inverse of level at pin 45 Inverse of level at pin 46
Table 18 Extended Audio Capability Register
REGISTER 2AH - EXTENDED AUDIO STATUS AND CONTROL REGISTER
The Extended Audio Status and Control Register is a read/write register that provides status and control of the extended audio features. DATA BIT VRA DRA VRM CDAC SDAC LDAC MADC PRI PRJ PRK PRL FUNCTION Enables variable rate audio mode Enable double rate audio mode Enables variable rate Mic ADC Indicates centre DAC ready Indicates surround DAC ready Indicates LFE DAC ready Indicates Mic ADC ready Set to turn off centre DAC Set to turn off surround DACs Set to turn off LFE DACs Set to turn off Mic ADC READ/WRITE Read/write Read/write Read/write Read Read Read Read Read/write Read/write Read/write Read/write WM9704M SUPPORT Yes No No Yes Yes Yes No Enable only Enable only Enable only No
Table 19 Extended Audio Status and Control Register
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REGISTER 2CH TO 32H - AUDIO SAMPLE RATE CONTROL REGISTERS
These registers are read/write registers that are written to, to select alternative sample rates for the audio PCM converters. Default is the 48ks/s rate. Note that only Rev 2.1 recommended rates are supported by the WM9704M, selection of any other unsupported rates will cause the rate to default to the nearest supported rate, and the supported rate value to be latched and so read back. Register 2Ch is the front DAC rate register, but is also used for centre channel data rate.
MODEM REGISTERS (INDEX 3CH TO 56H)
The contents of these registers control modem function.
REGISTER 3CH - EXTENDED MODEM ID
The extended modem ID is a read/write register that primarily identifies the enhanced codecs modem AFE capabilities. The default value will depend on features and hardware configuration. Writing any value to this register performs a warm modem AFE reset (register range 3C-56h), including GPIO (register range 4C-54h). The warm reset causes all affected registers to revert to their default values. Note: for AMC '97 parts the audio and modem AFE should be logically independent (writes to register 0h resets audio only). * * * * * * LIN1 = 1 indicates 1st line is supported - set when WM9704M is in Modem mode 1 = 1 LIN2 = 1 indicates 2nd line is supported - supported on WM9704M when DLM is set HSET = 1 indicates handset DAC/ADC is supported - not supported on WM9704M CID1 = 1 indicates that caller ID decode for line 1 is supported - not supported on WM9704M CID2 = 1 indicates that caller ID decode for line 2 is supported - not supported on WM9704M ID1, ID0 is a 2-bit field which indicates the Codec configuration: Primary is 00; Secondary is 01, 10, or 11
REGISTER 3EH - EXTENDED MODEM STATUS/CONTROL
The Extended Modem Status and Control register functions similarly to the original AC'97 Powerdown Control/Status register, located at index 26h. The (A)MC '97 Codec must restrict modem and handset power-down control/status to this register since all of the functions are provided here. Therefore, the (A)MC'97 Codec (and AC'97 Digital Controller, of course) must ignore bits MDM and PR7 in register 26h and use what is included here. When the GPIO section is powered down, all outputs must be tri-stated and input slot 12 should be marked invalid when the AC-link is active. When slot 12 is invalid, register 54h (GPIO Pin Status Register) will report 0s. In addition the Codec should force SDATA_IN slot 12 to all 0s. Bits 7 to 0 are read only, 1 indicates modem AFE subsystem readiness: * * * * * * * * GPIO = 1 indicates GPIO ready MREF = 1 indicates Modem VREFs up to nominal level ADC1 = 1 indicates Modem Line1 ADC ready DAC1 = 1 indicates Modem Line1 DAC ready ADC2 = 1 indicates Modem Line2 ADC ready - supported on WM9704M when in DLM is set DAC2 = 1 indicates Modem Line2 DAC ready -supported on WM9704M when DLM is set HADC = 1 indicates Handset ADC ready - not supported on WM9704M HDAC = 1 indicates Handset DAC ready - not supported on WM9704M
Bits 15 to 8 are read/write and control modem AFE subsystem power-down. WM9704M powerup/down functions are entirely controlled from register 26h. However, the following registers are aliased onto the appropriate control bits in registers 26h. * * * * * * * * PRA = 1 indicates GPIO power-down PRB = 1 indicates Modem VREF off - no separate modem VREF on WM9704M, aliases from PR3 PRC = 1 indicates Modem Line 1 ADC off - aliases from PR0 PRD = 1 indicates Modem Line 1 DAC off - aliases from PR1 PRE = 1 indicates Modem Line 2 ADC off - not supported on WM9704M PRF = 1 indicates Modem Line 2 DAC off - not supported on WM9704M PRG = 1 indicates Handset ADC off - not supported on WM9704M PRH = 1 indicates Handset DAC off - not supported on WM9704M
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Bits 7 to 0 are read only, 1 indicates modem AFE subsystem readiness. Bits 15 to 8 are read/write and control modem AFE subsystem power-down. Writing ENABLES (0) to the above aliased PR bits is allowed and will write enable to appropriate PRN bit. However, writing DISABLES (1) is not allowed.
REGISTER 40H - LINE1 ADC/DAC SAMPLE RATE
This read/write register 40h controls the modem DAC and ADC sample rate. This register is only functional if Modem mode 1 = 1 is selected from pins 30 and 40. The ADC will only use this sample rate if in addition, the input to the Record Mux is selected, as Right ADC is PHONE in register 1Ah. Note only the recommended sample rates are supported. If alternative sample rates are selected the rate will default to the nearest sample rate supported, and that value will be read back.
REGISTER 46H TO 48H - LINE1 AND 2 DAC/ADC LEVEL
These registers are not supported in WM9704M, register 04h being used to control TX modem level.
REGISTER 56H - MISCELLANEOUS MODEM AFE STATUS/CONTROL
This read/write register defines the loop back modes available for the modem line and handset ADCs/DACs described in the Intel Specification. Line1 ADC loopback mode 001 L1B0 is supported.
GPIO FUNCTION
Note that only the three GPIO pins are supported, GPIO 11 to 13.
REGISTER 4CH - GPIO PIN CONFIGURATION REGISTER
The GPIO Pin Configuration is a read/write register that specifies whether a GPIO pin is configured for input (1) or for output (0), and is accessed via the standard slot 1 and 2 command address/data protocols. If a GPIO pin is implemented, the respective GCx bit should be read/writeable and set to 1. If a GPIO is not implemented, then the respective GCx bit is read-only and set to 0. This informs the software how many GPIO pins have been implemented. It is up to the AC'97 Digital Controller to send the desired GPIO pin value over output slot 12 in the outgoing stream of the AC-link before configuring any of these bits for output. The default value after cold or register reset for this register (3800h) is all pins configured as inputs.
REGISTER 4EH - GPIO PINS POLARITY/TYPE
The GPIO Pin Polarity/Type is a read/write register that defines GPIO Input Polarity (0 = Low, 1 = High active) when a GPIO pin is configured as an Input. It defines GPIO Output Type (1 = CMOS, 0 = OPEN-DRAIN) when a GPIO pin is configured as an Output. The default value after cold or register reset for this register (FFFFh) is all pins active high. Non-implemented GPIO pins always return 1s.
REGISTER 50H - GPIO PIN STICKY CONTROL
The GPIO Pin Sticky is a read/write register that defines GPIO Input Type (0 = Non-sticky, 1 = Sticky) when a GPIO pin is configured as an input. GPIO inputs configured as sticky are cleared by writing a 0 to the corresponding bit of the GPIO pin status register 54h (see below), and by reset. The default value after cold or register reset for this register (0000h) is all pins Non-sticky. Unimplemented GPIO pins always return 0s. Sticky is defined as edge-sensitive, Non-sticky as level sensitive.
REGISTER 52H - GPIO PIN WAKE-UP CONTROL
The GPIO Pin Wake-up is a read/write register that provides a mask for determining if an input GPIO change will generate a wake-up or GPIO_INT (0 = No, 1 = Yes). When the AC-Link is powered down (Register 26h PR4 = 1 for primary codecs), a wake-up event will trigger the assertion of SDATA_IN. When AC-link is powered up, a wake-up event will appear as GPIO_INT = 1 on bit 0 of input slot 12. GPIO_INT is also flagged when the link is active. An AC-link wake-up Interrupt is defined as a 0 to 1 transition on SDATA_IN when the AC-Link is powered down (Register 26h PR4 = 1). GPIO bits that have been programmed as inputs, sticky and pin wake-up, upon transition either (high-to-low) or (low-to-high) depending on pin polarity, will cause an AC-link wake-up event (transition of SDATA_IN from 0 to 1), if and only if the AC-link was powered down. WOLFSON MICROELECTRONICS LTD
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Production Data The default value after cold or register reset for this register (0000h) defaults to all 0s specifying no wake-up event. Non-implemented GPIO pins always return 0s.
REGISTER 54H - GPIO PIN STATUS
The GPIO status is a read/write register that reflects the state of all GPIO pins (inputs and outputs) on slot 12. The value of all GPIO pin inputs and outputs comes in from the codec every frame on slot 12, but is also available for reading as GPIO Pin Status via the standard slot 1 and 2 command address/data protocols. GPIO inputs configured as Sticky are cleared by writing a 0 to the corresponding bit of this register 54h. Bits corresponding to unimplemented GPIO pins should be forced to zero in this register and input slot 12. GPIO bits that have been programmed as Inputs and Sticky, upon transition either (high-to low) or (low-to-high) depending on pin polarity, will cause the individual GPIO bit to go asserted 1, and remain asserted until a write of 0 to that bit. The normal way to set the desired value of a GPIO output pin is to set the control bit in output slot 12. The default value, if configured as an input, after cold or register reset for this register is always the state of the GPIO pin.
REGISTER 56H - MISCELLANEOUS MODEM AFE STATUS/CONTROL
This read/write register defines the loopback modes available for the modem line and handset ADCs/DACs described in the Intel Specification. Line1 ADC loopback mode 001 L1B0 is supported.
VENDOR RESERVED REGISTERS (INDEX 5AH AND 7AH)
These registers are vendor specific. Do not write to these registers unless the Vendor ID register has been checked first to ensure that the driver knows the source of the AC`97 component. Values stored in this register are used to provide vendor specific modes for the manufacturer. BIT AEV BB TRM HIC HIM DDS RTS DFT AFT DTS ATS User bits AND R2S I2S DLM ADS ADC no DAC Rev 2.1 switch I2S enable Dual line modem Automute disable 0 0 0 0 0 Select stereo mix into ADC as having no DAC signal Closes Rev 2.1 switch when set (see fig 1) Enables I2S data and clock onto GPIO pins 43,44,48 Selects support for Line2 DAC and ADC slots Disables automute function on the front and rear DACs NAME ADC evaluation BIASBOOST TSTRECMUX HALFICONV MALFIMIX Dither disable RAM test mode DAC FIT test ADC FIR test DAC test ADC test DEFAULT 0 0 0 0 0 0 0 0 0 0 0 ACTION WHEN SET TO 1 ADC evaluation mode select bit - do not use Increases analogue bias currents by 50% Enables record mux test mode; RECMUX outputs summed into the front and rear DAC output path. Halves to bias current to the converters Halves bias current to the mixer block Disables ADC and DAC digital dither - do not use Digital test mode - do not use Digital test mode - do not use Digital test mode - do not use Digital test mode - do not use Digital test mode - do not use
Test only bits - not normal use
Table 20 Vendor Register 5Ah Bit Allocation and Default States Vendor specific Gain control registers - (Index 70h to 74h). The function is as per the other mixer PGAs. However, the default value of the register changes depending upon the MODE the device is operating in, as shown in Table 21.
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DEFAULT VALUE FOR REGISTER
MODE Rev 2.1 (00) Modem (11)
REAR DAC - REG 70H 8808 0808
FRONT MIXER - REG 72H 0808 0808
REAR MIXER - REG 74H 8808 0808
REV 2.1 SWITCH Closed Open
Table 21 Vendor Specific PGA Default Values
VENDOR ID REGISTERS (INDEX 7CH TO 7EH)
This register is for specific vendor identification if so desired. The ID method is Microsoft's Plug and Play Vendor ID code. The first character of that ID is F7 to F0, the second character S7 to S0, and the third T7 to T0. These three characters are ASCII encoded. The REV7 to REV0 field is for the Vendor Revision number. In WM9704M the vendor ID is set to WML3 if MODE1 = 0, and WML4 if MODE1 = 1. Wolfson is a registered Microsoft Plug and Play vendor.
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The following table shows the function and address of the various control bits that are loaded through the serial interface during write operations. Reg 00h 02h 04h 06h 0Ah 0Ch 0Eh 10h 12h 14h 16h 18h 1Ah 1Ch 20h 22h 24h 26h 28h 2Ah 2Ch 2Eh 30h 32h 36h 38h 3Ch 3Eh 40h 42h 46h 48h 4Ch Name D15 D14 SE4 X X X X X X X X X X X X X ST X X PR6 ID0 PRL SR14 SR14 SR14 SR14 X X ID0 PRG SR14 D13 SE3 X X X X X X X X X X X X X 3D X X PR5 X PRK SR13 SR13 SR13 SR13 X X X PRF SR13 D12 SE2 ML4 ML4 X X X X GL4 GL4 GL4 GL4 GL4 X X lD X X PR4 X PRJ SR12 SR12 SR12 SR12 LFE4 LSR4 X PRE SR12 D11 SE1 ML3 ML3 X X X X GL3 GL3 GL3 GL3 GL3 X GL3 X X X PR3 X PRI SR11 SR11 SR11 SR11 LFE3 LSR3 X PD SR11 D10 SE0 ML2 ML2 X X X X GL2 GL2 GL2 GL2 GL2 SL2 GL2 X X X PR2 X X D9 ID9 ML1 ML1 X X X X GL1 GL1 GL1 GL1 GL1 D8 ID8 ML0 ML0 X X X X GL0 GL0 GL0 GL0 GL0 D7 ID7 X X X X X X X X X X X D6 ID6 X X X X X 20dB X X X X X D5 ID5 X X X X X X X X X X X X X X X X X X X D4 ID4 MR4 MR4 MM4 PV3 GN4 GN4 GR4 GR4 GR4 GR4 GR4 X X X X X X X X D3 ID3 MR3 MR3 MM3 PV2 GN3 GN3 GR3 GR3 GR3 GR3 GR3 X GR3 X DP3 X REF VRM VRM D2 ID2 MR2 MR2 MM2 PV2 GN2 GN2 GR2 GR2 GR2 GR2 GR2 SR2 GR2 X DP2 X ANL X X D1 ID1 MR1 MR1 MM1 PV0 GN1 GN1 GR1 GR1 GR1 GR1 GR1 SR1 GR1 X DP1 X DAC DRA DRA D0 ID0 MR0 MR0 MM0 X GN0 GN0 GR0 GR0 GR0 GR0 GR0 SR0 GR0 X DP0 X ADC VRA VRA Default 6140h 8000h 8000h 8000h 8000h 8008h 8008h 8808h 8808h 8808h 8808h 8808h 0000h 8000h 8000h 0000h 0000h 000Fh 0281h 0080h
Reset X Master volume Mute Headphone vol. Mute Master vol. mono Mute PCBEEP vol. Mute Phone volume Mute Mic volume Mute Line in volume Mute CD volume Mute Video volume Mute Aux volume Mute Frnt PCM out Mute volume Rec. select X Rec. gain Mute General purpose POP 3D control X Reserved X Pwrdwn ctrl/stat EAPD Ext'd audio ID ID1 Ext'd audio X ctrl/stat Front DAC rate SR15 Rear DAC rate SR15 LFE DAC rate SR15 Audio ADC rate SR15 6ch vol. C,LFE Mute 6ch vol. L,R surr Mute Ext'd mdm ID ID1 Ext'd mdm stat PRH Line1 sample SR15 rate ADC/DAC Line2 sample rate ADC/DAC Line1 DAC/ADC level Line2 DAC/ADC level GPIO pin config 0 1 0 0 0 CID2
SL1 SL0 X X GL1 GL0 X X MIX MS LPBK X X X X X X X X X PR1 PR0 X X Amap Ldac Sdac Cdac Madc Ldac Sdac Cdac
SR10 SR9 SR8 SR7 SR10 SR9 SR8 SR7 SR10 SR9 SR8 SR7 SR10 SR9 SR8 SR7 LFE2 LFE1 LFE0 Mute LSR2 LSR1 LSR0 Mute X X X X PRC PRB PRA DAC SR10 SR9 SR8 SR7
SR6 SR5 SR4 SR3 SR2 SR1 SR0 BB80h SR6 SR5 SR4 SR3 SR2 SR1 SR0 BB80h SR6 SR5 SR4 SR3 SR2 SR1 SR0 BB80h SR6 SR5 SR4 SR3 SR2 SR1 SR0 BB80h X X CNT4 CNT3 CNT2 CNT1 CNT0 0000h X X SR4 SR3 RSR2 RSR1 RSR0 8080h X X CID2 CID1 HSET LIN2 LIN1 x00xh ADC DAC2 DC2 DAC1 ADC1 MREF GPIO 0100h SR6 SR5 SR4 SR3 SR2 SR1 SR0 BB80h
Sample rates written to 42h will alias onto 40h Not supported - set TX modem levels by writing to rear DAC PGA 04h Not supported - set TX modem levels by writing to rear DAC PGA 04h 0 1 0 0 0 GC13 GC12 GC11 GP13 GP12 GP11 GS13 GS12 GS11
GW13 GW12 GW11
0 1 0 0 0
0 1 0 0 0
0 1 0 0 0
0 1 0 0 0 X
0 1 0 0 0
0 1 0 0 0
0 1 0 0 0
0 1 0 0 0 X
0 1 0 0 0
0 1 0 0 0
0 1 0 0 0
000Eh FFFFh 0000h 0000h 000xh
4Eh GPIO pin type 50h GPIO pin sticky 52h 54h 56h 5Ah 70h 72h 74h 7Ah 7Ch 7Eh GPIO wake-up GPIO pin status Misc. modem ctrl/stat Vendor rsvd test Rr PCM out vol. Front mixer vol. Rear mixer vol. Vendor rsvd Vendor ID1 Vendor ID2
GI13
GI12
GI11 X
CID1 CIDR MLNK
HSB2 HSB1 HSB0 AMD GL1 GL1 GL1 X F1 T1 DLM GL0 GL0 GL0 X F0 T0
L2B2 L2B1 L2B0
L1B2 L1B1 L1B0 0000h 0000h 0808h 0808h 8808h 0000h 574Dh 4C04h
ATST DTST AFTS DFTS RTST DDS Mute X X GL4 GL3 GL2 Mute X X GL4 GL3 GL2 Mute X X GL4 GL3 GL2 X X X X X X F7 F6 F5 F4 F3 F2 T7 T6 T5 T4 T3 T2
I2S R2S AND HIM HIC TRM BB AEV X X X GR4 GR3 GR2 GR1 GR0 X X X GR4 GR3 GR2 GR1 GR0 X X X GR4 GR3 GR2 GR1 GR0 X X X X X X X X S7 S6 S5 S4 S3 S2 S1 S0 Rev7 Rev6 Rev5 Rev4 Rev3 Rev2 Rev1 Rev0
Table 22 Serial Interface Register Map Description
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RECOMMENDED EXTERNAL COMPONENTS
DVDD AVDD 1
C1 C2
DVDD1 DVDD2 DVSS1 DVSS2
AVDD1 AVDD2 AVSS1 AVSS2
25 38
C3 C4
9 4 7
26 42
DGND
C5 C6 C7 C8 C9 C10
12 13 14 15 16 17 18 19 20
AGND PCBEEP PHONE AUXL AUXR VIDEOL VIDEOR CDL CDGND VREF VREFOUT AFILT1 CAP1 CAP2 27 28 29 31 32
C21 C22 C23 C25 C18 C19 C20
+
MIXER INPUTS
C11 C12 C13
+
C24
+
C26
+
AGND
WM9704M
AGND CX3D1 CX3D2 33 34
C27 C28
CDR C14 21 MIC1 C15 22 MIC2 C16 23 LINEINL C17 24 LINEINR AVDD 30 MODE0 MODE1 CID1 CID2
AGND LINEOUTL LINEOUTR MONOOUT LNLVLOUTL LNLVLOUTR 35 36 37 39 41
+ + + + +
C29 C30 C31 C32 C33
STEREO OUTPUT MONO OUTPUT LINE LEVEL STEREO
MODE OF OPERATION CONTROL
AVSS NOTES: 1. Pins 27, 29 and 31 are internally connected. It is recommended that capacitors only be connected to one of these pins. 2. C1 to C28 should be as close to WM9704M as possible. 3. AGND and DGND should be connected as close to WM9704M as possible.
40 46 45
5 6
SDATAOUT BITCLK SDATAIN SYNC RESETB XTLIN 2
XT C34 C35
GPIO1 GPIO2 GPIO3 EAPD XTLOUT 3
43 44 48 47
AC-LINK
8 10 11
TO I2S DACs
DGND
Figure 15 External Components Diagram
WOLFSON MICROELECTRONICS LTD
PD Rev 3.2 January 2001
35
WM9704M
RECOMMENDED EXTERNAL COMPONENTS VALUES
COMPONENT REFERENCE C1 to C4 C5 to C17 C18 C19 C20 C21 C22 C23 C24 C25 C26 C27 C28 C29 to C33 C34 and C35 XT SUGGESTED VALUE 10nF 470nF 1F 0.1F 10F 0.1F 10F 0.1F 10F 0.1F 10F 100nF 47nF 10F 22pF 24.576 MHz 3D low pass filter. This value sets nominal 100Hz. 3D high pass filter. This value sets nominal 1kHz. Output AC coupling caps to remove VREF DC level from outputs. Optional capacitors for better crystal frequency stability. DESCRIPTION De-coupling for DVDD and AVDD
Production Data
AC coupling capacitors for setting DC level of analogue inputs to VCAP1. Value chosen to give corner frequency below 20Hz for min 10K input impedance. Reference de-coupling capacitors for ADC, DAC, Mixer and CAP2 references. Ceramic type or similar.
AC'97 master clock frequency. A bias resistor is not required, but if connected will not affect operation if value is large (above 1M).
Table 23 External Component Values
RECOMMENDATIONS FOR 3.3V OPERATION
The device's performance with AVDD = 3.3V is shown in Electrical Characteristics. In 3.3V analogue operation, mid-rail reference scales to 1.5V. All ADC and DAC references are 3/5ths of their nominal 5V value. Input and output signals that are 1Vrms in 5V applications, scale to 660mVrms in 3.3V applications. If 1Vrms output is required, the mixer gain adjust PGAs need to be increased by 3 times 1.5dB steps.
WOLFSON MICROELECTRONICS LTD
PD Rev 3.2 January 2001
36
Production Data
WM9704M
PACKAGE DIMENSIONS
FT: 48 PIN TQFP (7 x 7 x 1.4 mm) DM003.B
b
e
25
36
37
24
E1
E
48
13
1
12
D1 D c
A A2
A1
L
-Cccc C
SEATING PLANE
Symbols A A1 A2 b c D D1 E E1 e L MIN ----0.05 1.35 0.17 0.09
ccc REF:
0.45 0o
Dimensions (mm) NOM --------1.40 0.22 ----9.00 BSC 7.00 BSC 9.00 BSC 7.00 BSC 0.50 BSC 0.60 3.5o
MAX 1.60 0.15 1.45 0.27 0.20
0.75 7o
Tolerances of Form and Position 0.08 JEDEC.95, MS-026
NOTES: A. ALL LINEAR DIMENSIONS ARE IN MILLIMETERS. B. THIS DRAWING IS SUBJECT TO CHANGE WITHOUT NOTICE. C. BODY DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSION, NOT TO EXCEED 0.25MM. D. MEETS JEDEC.95 MS-026, VARIATION = BBC. REFER TO THIS SPECIFICATION FOR FURTHER DETAILS.
WOLFSON MICROELECTRONICS LTD
PD Rev 3.2 January 2001
37

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