WOLFSON WM9712CLGEFL/V

w
WM9712L
AC’97 Audio and Touchpanel CODEC
DESCRIPTION
FEATURES
The WM9712L is a highly integrated input / output device
designed for mobile computing and communications. The
device can connect directly to a 4-wire or 5-wire touchpanel,
mono or stereo microphones, stereo headphones and a
mono speaker, reducing total component count in the
system. Additionally, phone input and output pins are
provided
for
seamless
integration
with
wireless
communication devices.
 AC’97 Rev 2.2 compatible stereo CODEC
- DAC SNR 94dB, THD –87dB
- ADC SNR 92dB, THD –87dB
- Variable Rate Audio, supports all WinCE sample rates
- Tone Control, Bass Boost and 3D Enhancement
 On-chip 45mW headphone driver
 On-chip 400mW mono speaker driver
 Stereo, mono or differential microphone input
- Automatic Level Control (ALC)
 Auxiliary mono DAC (ring tone or DC level generation)
 Seamless interface to wireless chipset
 Resistive touchpanel interface
- Supports 4-wire and 5-wire panels
- 12-bit resolution, INL 2 LSBs (<0.5 pixels)
- X, Y and touch-pressure (Z) measurement
- Pen-down detection supported in Sleep Mode
 Up to 5 GPIO pins
 2 comparator inputs for battery monitoring
 Up to 4 auxiliary ADC inputs
 1.8V to 3.6V supplies
 7x7mm QFN
The WM9712L also offers up to four auxiliary ADC inputs for
analogue measurements such as temperature or light, and
five GPIO pins for interfacing to buttons or other digital
devices. To monitor the battery voltage in portable systems,
the WM9712L has two uncommitted comparator inputs.
All device functions are accessed and controlled through a
single AC-Link interface compliant with the AC’97 standard.
Additionally, the WM9712L can generate interrupts to
indicate pen down, pen up, availability of touchpanel data,
low battery, dead battery, and GPIO conditions.
The WM9712L operates at supply voltages from 1.8 to 3.6
Volts. Each section of the chip can be powered down under
software control to save power. The device is available in a
small leadless 7x7mm QFN package, ideal for use in handheld portable systems.
APPLICATIONS
 Personal Digital Assistants (PDA)
 Smartphones
 Handheld and Tablet Computers
BLOCK DIAGRAM
WOLFSON MICROELECTRONICS plc
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Production Data, November 2011, Rev 4.6
Copyright 2011 Wolfson Microelectronics plc.
WM9712L
Production Data
TABLE OF CONTENTS
DESCRIPTION ....................................................................................................... 1 FEATURES ............................................................................................................ 1 APPLICATIONS..................................................................................................... 1 BLOCK DIAGRAM ................................................................................................ 1 TABLE OF CONTENTS ......................................................................................... 2 PIN CONFIGURATION .......................................................................................... 4 ORDERING INFORMATION .................................................................................. 4 PIN DESCRIPTION ................................................................................................ 5 ABSOLUTE MAXIMUM RATINGS ........................................................................ 6 RECOMMENDED OPERATING CONDITIONS ..................................................... 6 ELECTRICAL CHARACTERISTICS ..................................................................... 7 AUDIO OUTPUTS ............................................................................................................ 7 AUDIO INPUTS ................................................................................................................ 8 AUXILIARY MONO DAC (AUXDAC) ................................................................................ 8 TOUCHPANEL AND AUXILIARY ADC ............................................................................ 9 COMPARATORS ............................................................................................................. 9 REFERENCE VOLTAGES ............................................................................................. 10 DIGITAL INTERFACE CHARACTERISTICS ................................................................. 10 HEADPHONE / SPEAKER OUTPUT THD VERSUS POWER ...................................... 11 POWER CONSUMPTION .............................................................................................. 12 DEVICE DESCRIPTION ...................................................................................... 13 INTRODUCTION ............................................................................................................ 13 AUDIO PATHS OVERVIEW ........................................................................................... 14 AUDIO INPUTS.................................................................................................... 15 LINE INPUT .................................................................................................................... 15 MICROPHONE INPUT ................................................................................................... 15 PHONE INPUT ............................................................................................................... 17 PCBEEP INPUT ............................................................................................................. 18 AUDIO ADC ......................................................................................................... 19 RECORD SELECTOR.................................................................................................... 20 RECORD GAIN .............................................................................................................. 21 AUTOMATIC LEVEL CONTROL.................................................................................... 22 AUDIO DACS ...................................................................................................... 25 STEREO DAC ................................................................................................................ 25 AUXILIARY DAC ............................................................................................................ 28 ANALOGUE AUDIO OUTPUTS .......................................................................... 29 HEADPHONE OUTPUTS – HPOUTL AND HPOUTR ................................................... 29 EAR SPEAKER OUTPUT – OUT3 ................................................................................. 30 LOUDSPEAKER OUTPUTS – LOUT2 AND ROUT2 ..................................................... 31 PHONE OUTPUT (MONOOUT) ..................................................................................... 32 THERMAL SENSOR ...................................................................................................... 32 JACK INSERTION AND AUTO-SWITCHING ................................................................ 33 DIGITAL AUDIO (SPDIF) OUTPUT ............................................................................... 34 AUDIO MIXERS ............................................................................................................. 35 VARIABLE RATE AUDIO / SAMPLE RATE CONVERSION .............................. 37 TOUCHPANEL INTERFACE ............................................................................... 38 PRINCIPLE OF OPERATION - FOUR-WIRE TOUCHPANEL ....................................... 38 PRINCIPLE OF OPERATION - FIVE-WIRE TOUCHPANEL ......................................... 40 w
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WM9712L
CONTROLLING THE TOUCHPANEL DIGITISER ......................................................... 42 AUXILIARY ADC INPUTS ................................................................................... 47 BATTERY MEASUREMENT USING THE BMON/AUX3 PIN ........................................ 47 BATTERY ALARM AND ANALOGUE COMPARATORS ................................... 48 GPIO AND INTERRUPT CONTROL ................................................................... 51 POWER MANAGEMENT ............................................................................................... 55 AC97 DATA AND CONTROL INTERFACE ........................................................ 58 INTERFACE PROTOCOL .............................................................................................. 58 INTERFACE TIMING ..................................................................................................... 59 REGISTER MAP .................................................................................................. 62 REGISTER BITS BY ADDRESS .................................................................................... 63 APPLICATIONS INFORMATION ........................................................................ 71 RECOMMENDED EXTERNAL COMPONENTS ............................................................ 71 RECOMMENDED COMPONENTS VALUES ................................................................. 72 LINE OUTPUT ................................................................................................................ 72 AC-COUPLED HEADPHONE OUTPUT ........................................................................ 73 DC COUPLED (CAPLESS) HEADPHONE OUTPUT .................................................... 73 BTL LOUDSPEAKER OUTPUT ..................................................................................... 74 COMBINED HEADSET / BTL EAR SPEAKER .............................................................. 74 COMBINED HEADSET / SINGLE-ENDED EAR SPEAKER .......................................... 74 JACK INSERT DETECTION .......................................................................................... 75 HOOKSWITCH DETECTION ......................................................................................... 75 PACKAGE DRAWING ......................................................................................... 76 IMPORTANT NOTICE ......................................................................................... 77 ADDRESS: ..................................................................................................................... 77 REVISION HISTORY ........................................................................................... 78 w
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PIN CONFIGURATION
48
47
46
45
44
43
42
41
40
39
38
37
DBVDD
1
36
ROUT2
XTLIN
2
35
LOUT2
XTLOUT
3
34
SPKGND
DGND1
4
33
MONOOUT
SDATAOUT
5
32
CAP2
BITCLK
6
DGND2
7
SDATAIN
DCVDD
WM9712L
31
BMON / AUX3
30
COMP2 / AUX2
8
29
COMP1 / AUX1
9
28
MICBIAS
SYNC
10
27
VREF
RESETB
11
26
AGND
WIPER / AUX4
12
25
AVDD
QFN
13
14
15
16
17
18
19
20
21
22
23
24
ORDERING INFORMATION
DEVICE
TEMP. RANGE
o
WM9712CLGEFL/V
-25 to +85 C
WM9712CLGEFL/RV
-25 to +85 C
o
PACKAGE
MOISTURE LEVEL
SENSITIVITY
PEAK SOLDERING
TEMP
48-lead QFN
(Pb-free)
MSL3
260 C
48-lead QFN
(pb-free, tape and reel)
MSL3
260 C
o
o
Note:
Reel quantity = 2,200
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PIN DESCRIPTION
PIN
NAME
TYPE
DESCRIPTION
Digital I/O Buffer Supply
1
DBVDD
Supply
2
XTLIN
Digital Input
3
XTLOUT
Digital Output
4
DGND1
Supply
5
SDATAOUT
Digital Input
6
BITCLK
Digital Output
7
DGND2
Supply
8
SDATAIN
Digital Output
9
DCVDD
Supply
10
SYNC
Digital Input
Serial Interface Synchronisation Pulse from Controller
11
RESETB
Digital Input
Reset (asynchronous, active Low, resets all registers to their default)
12
WIPER / AUX4
Analogue Input
Top Sheet Connection for 5-wire Touchpanels / Auxiliary ADC Input
13
TPVDD
Supply
14
X+/BR
Analogue Input
Touchpanel Connection: X+ (Right) for 4-wire / bottom right for 5-wire
15
Y+/TR
Analogue Input
Touchpanel Connection: Y+ (Top) for 4-wire / top right for 5-wire
16
X-/TL
Analogue Input
Touchpanel Connection: X- (Left) for 4-wire / top left for 5-wire
17
Y-/BL
Analogue Input
Touchpanel Connection: Y- (Bottom) for 4-wire / bottom left for 5-wire
18
TPGND
Supply
19
PCBEEP
Analogue Input
Line Input to analogue audio mixers, typically used for beeps
20
PHONE
Analogue Input
Phone Input (RX)
21
MIC1
Analogue Input
Left Microphone or Microphone 1 Input
22
MIC2
Analogue Input
Right Microphone or Microphone 2 Input
23
LINEINL
Analogue Input
Left Line Input
24
LINEINR
Analogue Input
Right Line Input
25
AVDD
Supply
Analogue Supply (feeds audio DACs, ADCs, PGAs, mic boost, mixers)
26
AGND
Supply
Analogue Ground
27
VREF
Analogue Output
Internal Reference Voltage (buffered CAP2)
28
MICBIAS
Analogue Output
Bias Voltage for Microphones (buffered CAP2  1.8)
29
COMP1 / AUX1
Analogue Input
Comparator 1 (dead battery alarm) / Auxiliary ADC Input 1
30
COMP2 / AUX2
Analogue Input
Comparator 2 (low battery alarm) / Auxiliary ADC Input 2
31
BMON / AUX3
Analogue Input
Battery Monitor Input / Auxiliary ADC Input 3
32
CAP2
Analogue In / Out
Internal Reference Voltage (normally AVDD/2, if not overdriven)
33
MONOOUT
Analogue Output
Mono Output, intended for Phone TX signal
34
SPKGND
Supply
35
LOUT2
Analogue Output
Left Output 2 (Speaker, Line or Headphone)
36
ROUT2
Analogue Output
Right Output 2 (Speaker, Line or Headphone)
37
OUT3
Analogue Output
Analogue Output 3 (from AUXDAC or headphone pseudo-ground)
38
SPKVDD
Supply
39
HPOUTL
Analogue Output
40
HPGND
Supply
41
HPOUTR
Analogue Output
42
AGND2
Supply
Analogue Ground, Chip Substrate
43
HPVDD
Supply
Headphone Supply (feeds output buffers on pins 37, 39, 41)
44
GPIO1
Digital In / Out
GPIO Pin 1
45
GPIO2 / IRQ
Digital In / Out
GPIO Pin 2 or IRQ (Interrupt Request) Output
46
GPIO3 / PENDOWN
Digital In / Out
GPIO Pin 3 or Pen Down Output
47
GPIO4 / ADA / MASK
Digital In / Out
GPIO Pin 4 or ADA (ADC Data Available) Output or Mask input (On
reset, pin level configures device power up status. See Applications
section for external components configuration)
48
GPIO5 / SPDIF_OUT
Digital In / Out
GPIO Pin 5 or SPDIF Digital Audio Output
Clock Crystal Connection 1 / External Clock Input
Clock Crystal Connection 2
Digital Ground (return path for both DCVDD and DBVDD)
Serial Data Output from Controller / Input to WM9712L
Serial Interface Clock Output to Controller
Digital Ground (return path for both DCVDD and DBVDD)
Serial Data Input to Controller / Output from WM9712L
Digital Core Supply
Touchpanel Driver Supply
Touchpanel Driver Ground
Speaker Ground (feeds output buffers on pins 35 and 36)
Speaker Supply (feeds output buffers on pins 35 and 36)
Headphone Left Output
Headphone Ground (feeds output buffers on pins 37, 39, 41)
Headphone Right Output
Note: It is recommended that the QFN ground paddle should be connected to analogue ground on the application PCB.
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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.
Wolfson tests its package types according to IPC/JEDEC J-STD-020B for Moisture Sensitivity to determine acceptable storage
conditions prior to surface mount assembly. These levels are:
MSL1 = unlimited floor life at <30C / 85% Relative Humidity. Not normally stored in moisture barrier bag.
MSL2 = out of bag storage for 1 year at <30C / 60% Relative Humidity. Supplied in moisture barrier bag.
MSL3 = out of bag storage for 168 hours at <30C / 60% Relative Humidity. Supplied in moisture barrier bag.
The Moisture Sensitivity Level for each package type is specified in Ordering Information.
CONDITION
MIN
MAX
Digital supply voltages (DCVDD, DBVDD)
-0.3V
+3.63V
Analogue supply voltages (AVDD, HPVDD, SPKVDD, TPVDD)
-0.3V
+3.63V
Touchpanel supply voltage (TPVDD)
AVDD -0.3V
AVDD +0.3V
Voltage range digital inputs
DGND -0.3V
DBVDD +0.3V
Voltage range analogue inputs
AGND -0.3V
AVDD +0.3V
Voltage range touchpanel Inputs X+, X-, Y+ and Y-
TPVDD +0.3V
Voltage range touchpanel Inputs X+, X-, Y+ and Y-
AVDD +0.3V
Voltage range, BMON/AUX3 (pin31)
+5V
o
Operating temperature range, TA
o
-25 C
+85 C
RECOMMENDED OPERATING CONDITIONS
PARAMETER
SYMBOL
TEST CONDITIONS
MIN
TYP
MAX
UNIT
Digital input/output buffer
supply range
DBVDD
Notes 1, 2
1.8
3.6 or
AVDD+0.3
V
Digital core supply range
DCVDD
Notes 1, 2
1.8
3.6 or
AVDD+0.3
V
1.8
3.6
V
Analogue supply range
AVDD, HPVDD,
SPKVDD, TPVDD
Digital ground
DCGND, DBGND
0
V
Analogue ground
AGND, HPGND,
SPKGND, TPGND
0
V
Difference AGND to DGND
Note 3
-0.3
0
+0.3
V
Notes:
1.
AVDD, DCVDD and DBVDD can all be different
2.
Digital supplies (DCVDD, DBVDD) must not exceed analogue supplies (AVDD, HPVDD, SPKVDD, TPVDD) by more
than 0.3V
3.
AGND is normally the same as DGND
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ELECTRICAL CHARACTERISTICS
AUDIO OUTPUTS
Test Conditions
o
DBVDD=3.3V, DCVDD = 3.3V, AVDD=HPVDD=SPKVDD =3.3V, TA = +25 C, 1kHz signal, fs = 48kHz, 18-bit audio data unless
otherwise stated.
PARAMETER
SYMBOL
TEST CONDITIONS
MIN
TYP
MAX
UNIT
DAC to Line-Out (HPOUTL/R or MONOOUT with 10k / 50pF load)
Full-scale output
Signal to Noise Ratio
AVDD = 3.3V, PGA gains
set to 0dB
SNR
85
1
V rms
94
dB
(A-weighted)
Total Harmonic Distortion
Power Supply Rejection
THD
-3dB output
-87
PSRR
100mV, 20Hz to 20kHz
signal on AVDD
50
-80
dB
dB
Speaker Output (LOUT2/ROUT2 with 8 bridge tied load, INV=1)
Output Power
PO
Output Power at 1% THD
PO
400
mW
POmax
500
mW
-66
dB
Abs. Max Output Power
Total Harmonic Distortion
Signal to Noise Ratio
THD
Output power is very closely correlated with THD; see below.
PO=200mW
SNR
90
0.05
%
100
dB
(A-weighted)
Headphone Output (HPOUTL/R, OUT3 or LOUT2/ROUT2 with 16 or 32 load)
Output Power per channel
PO
Total Harmonic Distortion
THD
Signal to Noise Ratio
SNR
Output power is very closely correlated with THD; see below.
PO=10mW, RL=16
-76
PO=10mW, RL=32
-73
PO=20mW, RL=16
-75
PO=20mW, RL=32
-78
90
dB
-70
95
dB
(A-weighted)
Note:
1.
All THD values are valid for the output power level quoted above – for example, at HPVDD=3.3V and RL=16, THD is
–76dB when output power is 10mW. Higher output power is possible, but will result in a deterioration in THD.
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AUDIO INPUTS
Test Conditions
o
DBVDD=3.3V, DCVDD = 3.3V, AVDD = 3.3V, TA = +25 C, 1kHz signal, fs = 48kHz, 18-bit audio data unless otherwise stated.
PARAMETER
SYMBOL
TEST CONDITIONS
MIN
TYP
MAX
UNIT
LINEINL/R, MICL/R and PHONE pins
Full Scale Input Signal Level
VINFS
AVDD = 3.3V
1.0
AVDD = 1.8V
0.545
differential input mode
(MS = 01)
half of the value listed above
(for ADC 0dB Input at 0dB Gain)
Input Resistance
0dB PGA gain
RIN
12dB PGA gain
V rms
34
10
16
Input Capacitance
k
22
5
pF
92
dB
Line input to ADC (LINEINL, LINEINR, PHONE)
Signal to Noise Ratio
SNR
85
(A-weighted)
Total Harmonic Distortion
Power Supply Rejection
THD
-6dBFs
-87
PSRR
20Hz to 20kHz
50
-80
dB
dB
SNR
20dB boost enabled
80
dB
THD
20dB boost enabled
-80
dB
50
dB
TBD
dB
Microphone input to ADC (MIC1/2 pins)
Signal to Noise Ratio
(A-weighted)
Total Harmonic Distortion
Power Supply Rejection Ratio
PSRR
Common Mode Rejection Ratio
CMRR
Differential mic mode
AUXILIARY MONO DAC (AUXDAC)
Test Conditions
o
AVDD = 3.3V, TA = +25 C, unless otherwise stated.
PARAMETER
SYMBOL
TEST CONDITIONS
MIN
Resolution
Full scale output voltage
Signal to Noise Ratio
AVDD=3.3V
SNR
65
TYP
MAX
UNIT
12
bits
1
Vrms
70
dB
(A-weighted)
Total Harmonic Distortion
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THD
-62
-50
dB
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TOUCHPANEL AND AUXILIARY ADC
Test Conditions
o
DBVDD=3.3V, DCVDD = 3.3V, AVDD = TPVDD = 3.3V, TA = +25 C, MCLK = 24.576 MHz, unless otherwise stated.
PARAMETER
SYMBOL
TEST CONDITIONS
MIN
TYP
MAX
UNIT
Input Pins X+, X-, Y+, Y-, WIPER/AUX4, COMP1/AUX1, COMP2/AUX2 and BMON/AUX3
Input Voltage
AGND
Input leakage current
AUX pin not selected as
AUX ADC input
AVDD
<10
ADC Resolution
12
Differential Non-Linearity Error
DNL
Integral Non-Linearity Error
INL
0.25
V
nA
bits
1
LSB
2
LSB
Offset Error
4
LSB
Gain Error
6
LSB
48
kHz
6
ms
Power Supply Rejection
PSRR
50
Throughput Rate
DEL = 1111
dB
(zero settling time)
Settling Time (programmable)
MCLK = 24.576MHz
Conversion Time
0
Switch matrix resistance
Programmable Pull-up resistor

12
RPU
RPU = 000001
55
Pen down detector threshold
Pressure measurement current
s
20.8
Note: touch pressure
measurements require two
conversions
IP
63
70
k
VDD/2
V
PIL = 1
400
A
PIL = 0
200
BMON/AUX3 (pin 31 only)
Input Range
AVDD = 3.3V
AGND
5
V
AVDD = 1.8V
AGND
3.3
V
Scaling
-3%
Input Resistance (Note 1)
1/3
during measurement
30
average over time
30 /
+3%
k
duty cycle
Note:
1. Current only flows into pin 31 during a measurement. At all other times, BMON/AUX3 is effectively an open circuit.
COMPARATORS
Test Conditions
o
AVDD = 3.3V, TA = +25 C, unless otherwise stated.
PARAMETER
SYMBOL
TEST CONDITIONS
MIN
TYP
MAX
UNIT
COMP1/AUX1 and COMP2/AUX2 (pins 29, 30)
Input Voltage
Input leakage current
AGND
pin not selected as AUX
ADC input
Comparator Input Offset
AVDD
<10
V
nA
-50
+50
mV
0
10.9
s
(COMP1, COMP2 only)
COMP2 delay (COMP2 only)
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24.576MHz crystal
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REFERENCE VOLTAGES
Test Conditions
o
DBVDD=3.3V, DCVDD = 3.3V, AVDD = 3.3V, TA = +25 C, 1kHz signal, fs = 48kHz, 18-bit audio data unless otherwise stated.
PARAMETER
SYMBOL
TEST CONDITIONS
MIN
TYP
MAX
UNIT
Audio ADCs, DACs, Mixers
Reference Input/Output
CAP2 pin
1.6
1.65
1.7
V
Buffered Reference Output
VREF pin
1.6
1.65
1.7
V
Bias Voltage
VMICBIAS
2.88
2.97
3.06
V
Bias Current Source
IMICBIAS
3
mA
Output Noise Voltage
Vn
Microphone Bias
1K to 20kHz
15
nV/Hz
DIGITAL INTERFACE CHARACTERISTICS
Test Conditions
o
DBVDD = 3.3V, DCVDD = 3.3V, TA = +25 C, unless otherwise stated.
PARAMETER
SYMBOL
TEST CONDITIONS
MIN
TYP
MAX
UNIT
Digital Logic Levels (all digital input or output pins) – CMOS Levels
Input HIGH level
VIH
Input LOW level
VIL
Output HIGH level
VOH
source current = 2mA
Output LOW level
VOL
sink current = 2mA
DBVDD0.7
V
DBVDD0.3
V
DBVDD0.9
DBVDD0.1
Clock Frequency
Master clock (XTLIN pin)
24.576
MHz
AC’97 bit clock (BIT_CLK pin)
12.288
MHz
AC’97 sync pulse (SYNC pin)
48
kHz
Note:
1.
All audio and non-audio sample rates and other timing scales proportionately with the master clock.
2.
For signal timing on the AC-Link, please refer to the AC’97 specification (Revision 2.2)
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HEADPHONE / SPEAKER OUTPUT THD VERSUS POWER
-20
Headphone Power vs THD+N (32Ohm load)
THD+N (dB)
-40
-60
-80
-100
0
5
10
15
20
25
30
40
50
60
Power (mW)
-20
Headphone Power vs THD+N (16Ohm load)
THD+N (dB)
-40
-60
-80
-100
0
10
20
30
Power (mW)
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POWER CONSUMPTION
The power consumption of the WM9712L depends on the following factors.

Supply voltages: Reducing the supply voltages also reduces digital supply currents, and therefore results in significant
power savings especially in the digital sections of the WM9712L.

Operating mode: Significant power savings can be achieved by always disabling parts of the WM9712L that are not
used (e.g. audio ADC, DAC, touchpanel digitiser).
Mode Description
26h 14:8
OFF (lowest possible power)
Clocks stopped
1111111 0111111111111111 58h, SVD = 1
LPS (Low Power Standby)
VREF maintained using 1MOhm string
1111111 0111111111111111
Standby Mode (ready to playback)
VREF maintained using 50kOhm string
1110111 0111111111111111
"Idle" Mode
VREF maintained using 50kOhm string
use LPS mode instead, if possible
Touchpanel only (waiting for pen-down)
AC-Link running
1100111 0111111111111111
1101111 0111111111111111 76h = 0C00h
78h = 0001h
Touchpanel only (continuous conversion)
93.75 points per second
1001111 0111111111111111 76h = 0C00h
78h = C001h
Phone Call - using headphone / ear speaker
HPOUTL, HPOUTR and OUT3 active
AC-Link stopped
Phone Call - using loudspeaker
AC-Link stopped
0110011 0111100010101100 0Eh, bit 7 = 1
(mic gain boost)
Record from mono microphone
with MICBIAS
all analogue outputs disabled
Record phone call
both sides mixed to mono
call using headphone / ear speaker
DAC Playback - using loudspeaker
24h 15:0
Other Settings
1110011 0111101100110100 0Eh, bit 7 = 1
(mic gain boost)
1000110 0110101111111111 0Eh, bit 7 = 1
(mic gain boost)
0000000 0000000010001000 0Eh, bit 7 = 1
(mic gain boost)
1000001 0001111101110111
DAC Playback - using headphone
0000001 0001110011101111
DAC Playback - to Line-out
0000001 0001110011110111
Maximum Power (everything on)
0000000 0000000000000000 0Eh, bit 7 = 1
(mic gain boost)
V
3.3
2.5
1.8
3.3
2.5
1.8
3.3
2.5
1.8
3.3
2.5
1.8
3.3
2.5
1.8
3.3
2.5
1.8
3.3
2.5
1.8
3.3
2.5
1.8
3.3
2.5
1.8
3.3
2.5
1.8
3.3
2.5
1.8
3.3
2.5
1.8
3.3
2.5
1.8
3.3
2.5
1.8
AVDD
I (mA)
0.0005
0.0004
0.0003
0.005
0.004
0.003
0.56
0.37
0.241
1.1
0.76
0.508
0.05
0.02
0.009
0.08
0.04
0.027
2.36
1.838
1.218
2.385
1.837
1.218
3.27
2.66
1.838
9.461
7.46
5.318
3.45
2.549
1.738
3.62
2.71
1.748
3.62
2.71
1.748
9.593
7.37
5.388
V
3.3
2.5
1.8
3.3
2.5
1.8
3.3
2.5
1.8
3.3
2.5
1.8
3.3
2.5
1.8
3.3
2.5
1.8
3.3
2.5
1.8
3.3
2.5
1.8
3.3
2.5
1.8
3.3
2.5
1.8
3.3
2.5
1.8
3.3
2.5
1.8
3.3
2.5
1.8
3.3
2.5
1.8
DCVDD
I (mA)
0
0
0
0
0
0
0
0
0
0
0
0
1.301
0.883
0.571
5.85
3.922
2.87
0
0
0
0
0
0
11.21
7.78
5.21
12.22
8.552
5.799
9.884
6.755
4.606
9.8
6.78
4.606
9.8
6.78
4.606
12.26
8.563
5.8
V
3.3
2.5
1.8
3.3
2.5
1.8
3.3
2.5
1.8
3.3
2.5
1.8
3.3
2.5
1.8
3.3
2.5
1.8
3.3
2.5
1.8
3.3
2.5
1.8
3.3
2.5
1.8
3.3
2.5
1.8
3.3
2.5
1.8
3.3
2.5
1.8
3.3
2.5
1.8
3.3
2.5
1.8
DBVDD
I (mA)
0
0
0
0
0
0
0
0
0
0
0
0
3.26
2.1
1.41
2.67
2.1
1.41
0
0
0
0
0
0
2.6
2.13
1.41
2.62
2.1
1.48
2.6
2.1
1.41
2.6
2.1
1.47
2.6
2.1
1.41
2.62
2.12
1.48
Total Power
(mW)
0.00165
0.001
0.00054
0.0165
0.01
0.0054
1.848
0.925
0.4338
3.63
1.9
0.9144
15.2163
7.5075
3.582
28.38
15.155
7.7526
7.788
4.595
2.1924
7.8705
4.5925
2.1924
56.364
31.425
15.2244
80.1933
45.28
22.6746
52.5822
28.51
13.9572
52.866
28.975
14.0832
52.866
28.975
13.9752
80.7609
45.1325
22.8024
Table 1 Supply Current Consumption
Notes:
o
1.
All figures are at TA = +25 C, audio sample rate fs = 48kHz, with zero signal (quiescent).
2.
The power dissipated in the headphone, speaker and touchpanel is not included in the above table.
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DEVICE DESCRIPTION
INTRODUCTION
The WM9712L is designed to meet the mixed-signal requirements of portable and wireless computer
systems. It includes audio recording and playback, touchpanel digitisation, battery monitoring,
auxiliary ADC and GPIO functions, all controlled through a single 5-wire AC-Link interface.
SOFTWARE SUPPORT
The basic audio features of the WM9712L are software compatible with standard AC’97 device
drivers. However, to better support the touchpanel and other additional functions, Wolfson
Microelectronics supplies custom device drivers for selected CPUs and operating systems. Please
contact your local Wolfson Sales Office for more information.
AC’97 COMPATIBILITY
The WM9712L uses an AC’97 interface to communicate with a microprocessor or controller. The
audio and GPIO functions are largely compliant with AC’97 Revision 2.2. The following differences
from the AC’97 standard are noted:




Pinout: The function of some pins has been changed to support device specific features.
The PHONE and PCBEEP pins have been moved to different locations on the device
package.
Package: The package for the WM9712L is a 77mm leadless QFN package.
Audio mixing: The WM9712L handles all the audio functions of a smartphone, including
audio playback, voice recording, phone calls, phone call recording, ring tones, as well as
simultaneous use of these features. The AC’97 mixer architecture does not fully support
this. The WM9712L therefore uses a modified AC’97 mixer architecture with three
separate mixers.
Tone Control, Bass Boost and 3D Enhancement: These functions are implemented in the
digital domain and therefore affect only signals being played through the audio DACs, not
all output signals as stipulated in AC’97.
Some other functions are additional to AC’97:
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
On-chip BTL loudspeaker driver


On-chip BTL driver for ear speaker (phone receiver)
Auxiliary mono DAC for ring tones, system alerts etc.


Touchpanel controller
Auxiliary ADC Inputs


2 Analogue Comparators for Battery Alarm
Programmable Filter Characteristics for Tone Control and 3D Enhancement
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AUDIO PATHS OVERVIEW
L
18h:12-8
00000 = +12dB
11111 = -34.5dB
20h:7
(Loopback)
ADC Left
1
AC Link
0
Slot 3
Tone and 3D
08h / 22h /
20h:13 (3DE)
Left Channel
18 Bit DAC
18
h
10 :15
h:
1
0C 5
h:1
5
0Ah
:15
-12
14h:15-12
6dB -> -15dB
10h:12-8
00000 = +12dB
11111 = -34.5dB
LINEINL
Pin 23
L Line Volume
02h:12-8
00000 = 0dB
11111 = -46.5dB
to SPKR MIXER
PCM
PGA
6dB -> -15dB
to SPKR MIXER
LINEL PGA
6dB -> -15dB
6dB -> -15dB
LOUT2
Pin 35
0
02h:6 (INV)
1
-12
14h:15
1-7
h:1 7
14
11 2
h:
14 5-1
1
h:
12
6dB -> -15dB
PCBEEP
Pin 19
1
headphone
mixer L
0
16h:8 (SRC)
HPOUTL
Pin 39
PHONE PGA
Zerocross
detect
10
h
10 :13
h:
1
18 3
h:1
3
18h
:13
6dB -> -15dB
0Eh:12-8
00000 = +12dB
11111 = -34.5dB
0Ah7:4
Mono Volume
06h:4-0
00000 = 0dB
11111 = -46.5dB
14+7
0Eh:
7
3+
h:1 1
0E
-1
13
h:
1A
0dB / 20dB
MICL PGA
0dB / 20dB
OEh:6-5 (MS)
04h:7 (ZC)
04h:15 (MUTE)
Phone
Mixer
1
12 Ah:
h: 13
7- - 1
4
1
MIC1
Pin 21
02h:7 (ZC)
02h:15 (MUTE)
L Headphone Volume
04h:12-8
00000 = 0dB
11111 = -46.5dB
6dB -> -15dB
0Ch:0-4
00000 = +12dB
11111 = -34.5dB
PHONE
Pin 20
Zerocross
detect
0dB / 20dB
MONOOUT
Pin 33
Zerocross
detect
0dB / 20dB
6dB -> -15dB
06h:7 (ZC)
06h:15 (MUTE)
PCBEEP
PHONE
1Ah[10:8] = 110
MONOMIX
SPKRMIX
DACR
Note: MS bits
also affect
sidetone path
1Ah[10:8] = 101
(1Ah[10:8] = 000) & (MS = 01)
(1Ah[10:8] = 000) & (MS = 00 or 11)
1Ah[10:8] = 111
1Ah:
10-8
Gain Ranges:
1Ch:13 (GRL=0)
1Ch:11:8
0000 = 0db
1111 = +22.5dB
1Ch:6 (GRL=1)
1Ch:13-8
11111 = +30dB
00000 = -17.25dB
AUXDAC
1Ah:14
0 = 0dB
1 = 20dB
Left Channel
18 Bit ADC
Variable Slot
5C:1-0 (ASS)
5C:3 (HPF)
5C:4 (ADCO)
ADC
PGA 1Ch:15 (Mute)
1Ah[10:8] = 100
OUT3 Volume
16h:4-0
00000 = 0dB
11111 = -46.5dB
LINER
MICR
MICL
ALCL
ALCR
(1Ah[10:8] = 000) & (MS = 10)
1Ah[10:8] = 011
OUT3
37
Zero- Pin
cross
detect
16h:10-9
(OUT3SRC)
AC Link
16h:7 (ZC)
16h:15 (MUTE)
ALC:5Ch/60h/62h
AUXDAC
ALCR
ALCL
MICL
MICR
LINER
DACR
R
20h:7
(Loopback)
ADC Right
1
AC Link
0
Slot 4
Tone and 3D
08h / 22h /
20h:13 (3DE)
Right Channel
18 Bit DAC
10h:5-0
00000 = +12dB
11111 = -34.5dB
LINEINR
Pin 24
PHONE
18h:4-0
00000 = +12dB
11111 = -34.5dB
PCBEEP
MONOMIX
SPKRMIX
PCM
PGA
12 Bit Resistor
string DAC
2Eh/64h/12h:0(EN)
LINER PGA
18
h
10 :15
h:
1
0C 5
h:1
6dB -> -15dB
5
0Ah
:15-1
2
6dB -> -15dB
14h:15-12
5Ch:8 (DS)
0Eh:5-0
00000 = +12dB
11111 = -34.5dB
MS = 01
6dB -> -15dB
MICR PGA
MS = 10 or 11
6dB -> -15dB
0Eh:6-5
(MS)
6dB -> -15dB
Note: MS bits also
affect ADC input
path from MICs
MIC2
Pin 22
R Headphone Volume
04h:4-0
00000 = 0dB
11111 = -46.5dB
headphone
mixer R
HPOUTR
Pin 41
2
15-1
14h:
1-8
h:1 8
14
1
1 2
h:
14 5-1
1
h:
12
Zerocross
detect
04h:7 (ZC)
04h:15 (MUTE)
6dB -> -15dB
R Line Volume
02h:4-0
00000 = 0dB
11111 = -46.5dB
FROM
LINEL
PGA
FROM
DACL
10
h:
10 14
h1
4
18
h:1
4
18h
:14
16h:8 (SRC)
0
Zerocross
detect
0Ch:14
6dB -> -15dB
1Ah[2:0] = 110
6dB -> -15dB
Note: MS bits
also affect
1Ah[2:0] = 101
sidetone path
(1Ah[2:0] = 000) & (MS = 01)
(1Ah[2:0] = 000) & (MS = 10 or 11)
(1Ah[2:0] = 000) & (MS = 00)
1Ah:
2-0
Gain Ranges:
1Ch:6 (GRR=0)
1Ch:3:0
0000 = 0db
1111 = +22.5dB
1Ch:6 (GRR=1)
1Ch:5-0
11111 = +30dB
00000 = -17.25dB
1Ah[2:0] = 111
1Ah[2:0] = 100
1Ah[2:0] = 011
ADC
PGA
1Ch:15 (Mute)
ROUT2
Pin 36
1
Speaker
Mixer
02h:7 (ZC)
02h:15 (MUTE)
11-8
0Ah:
1-8
h:1
12
PR3 (REF disable) &
58h:10 (SVD)
1Ah:14
0 = 0dB
1 = 20dB
4.5k
Right Channel
18 Bit ADC
Variable Slot
5C:1-0 (ASS)
5C:3 (HPF)
5C:4 (ADCO)
AC Link
500k
AVDD
Pin 25
MICBIAS
Pin 28
50k
50k
500k
ALC:5Ch/60h/62h
3.6k
AGND
Pin 24
CAP2
Pin 32
VREF
Pin 27
Figure 1 Audio Paths Overview
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AUDIO INPUTS
The following sections give an overview of the analogue audio input pins and their function. For more
information on recommended external components, please refer to the “Applications Information”
section.
LINE INPUT
The LINEINL and LINEINR inputs are designed to record line level signals, and/or to mix into one of
the analogue outputs.
Both pins are directly connected to the record selector. The record PGA adjusts the recording volume,
controlled by register 1Ch or by the ALC function.
For analogue mixing, the line input signals pass through a separate PGA, controlled by register 10h.
The signals can be routed into all three output mixers (headphone, speaker and phone). Each
LINEIN-to-mixer path has an independent mute bit. When the line inputs are not used, the line-in PGA
can be switched off to save power (see “Power Management” section).
LINEINL and LINEINR are biased internally to the reference voltage VREF. Whenever the inputs are
muted or the device placed into standby mode, the inputs remain biased to VREF using special antithump circuitry to suppress any audible clicks when changing inputs.
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
10h
12:8
LINEINL
01000
LINEINL input gain
VOL
(0dB)
00000: +12dB
… (1.5dB steps)
11111: -34.5dB
4:0
15
LINEINR
01000
LINEINR input gain
VOL
(0dB)
similar to LINEINLVOL
L2H
1
Mute LINEIN path to headphone mixer
1: Mute, 0: No mute (ON)
14
L2S
1
Mute LINEIN path to speaker mixer
1: Mute, 0: No mute (ON)
13
L2P
1
Mute LINEIN path to phone mixer
1: Mute, 0: No mute (ON)
Table 2 Line Input Control
MICROPHONE INPUT
The MIC1 and MIC2 inputs are designed for direct connection to single-ended mono, stereo or
differential mono microphone. If the microphone is mono, the same signal appears on both left and
right channels. In stereo mode, MIC1 is routed to the left and MIC2 to the right channel.
For voice recording, the microphone signal is directly connected to the record selector. The record
PGA adjusts the recording volume, controlled by register 1Ch or by the ALC function.
For analogue mixing, the signal passes through a separate PGA, controlled by register 0Eh. The
microphone signal can be routed into the phone mixer (for normal phone call operation) and/or the
headphone mixer (using register 14h, see “Audio Mixers / Sidetone Control” section), but not into the
speaker mixer (to prevent acoustic feedback from the speaker into the microphone). When the
microphone inputs are not used, the microphone PGA can be switched off to save power (see “Power
Management” section).
MIC1 and MIC2 are biased internally to the reference voltage VREF. Whenever the inputs are muted
or the device placed into standby mode, the inputs remain biased to VREF using special anti-thump
circuitry to suppress any audible clicks when changing inputs.
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It is also possible to use the LINEINL and LINEINR pins as a second differential microphone input.
This is achieved by setting the DS bit (register 5Ch, bit 11) to ‘1’. This disables the line-in audio paths
and routes the signal from LINEINL and LINEINR through the differential mic path, as if it came from
the MIC1 and MIC2 pins. Only one differential microphone be used at a time. The DS bit only has an
effect when MS = 01 (differential mode).
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
0Eh
14
M12P
1
Mute MIC1 path to phone mixer
13
M22P
1
Mute MIC2 path to phone mixer
12:8
LMICVOL
01000
Left microphone volume
(0dB)
Only used when MS = 11
Mic Volume
1: Mute, 0: No mute (ON)
1: Mute, 0: No mute (ON)
Similar to MICVOL
7
20dB
0
Microphone gain boost (Note 1)
1: 20dB boost ON
0: No boost (0dB gain)
6:5
MS
00
Microphone mode select
00
Single-ended mono (left)
left = right = MIC1 (pin 21)
Volume controlled by MICVOL
01
Differential mono mode
left = right = MIC1 – MIC2
Volume controlled by MICVOL
10
Single-ended mono (right)
left = right = MIC2 (pin 22)
Volume controlled by MICVOL
11
Stereo mode
MIC1 = left, MIC2 = right
Left Volume controlled by LMICVOL
Right volume controlled by MICVOL
4:0
MICVOL
01000
Microphone volume to mixers
(0dB)
00000: +12dB
… (1.5dB steps)
11111: -34.5dB
5Ch
8
DS
Additional
Analogue
Functions
0
Differential Microphone Select
0 : Use MIC1 and MIC2
1: Use LINEL and LINER (Note 2)
Table 3 Microphone Input Control
Note:
1.
The 20dB gain boost acts on the input to the phone mixer only. A separate microphone
boost for recording can be enabled using the BOOST bit in register 1Ah.
2.
When the LINEL and LINER are selected for differential microphone select then the
MIC1 and MIC2 input pins become disabled, these signals can therefore not be routed
internally to the device.
MICROPHONE BIAS
The MICBIAS output (pin 28) provides a low noise reference voltage suitable for biasing electret type
microphones and the associated external resistor biasing network. The internal MICBIAS circuitry is
shown below. Note that the maximum source current capability for MICBIAS is 3mA. The external
biasing resistors and microphone cartridge therefore must limit the MICBIAS current to 3mA.
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CAP2
MICBIAS
= 1.8 x CAP2
= 0.9 X AVDD
WM9712L
AGND
Figure 2 Microphone Bias Schematic
PHONE INPUT
Pin 20 (PHONE) is a mono, line level input designed to connect to the receive path of a telephony
device.
The pin connects directly to the record selector for phone call recording (Note: to record both sides of
a phone call, one ADC channel should record the PHONE signal while the other channel records the
MIC signal). The RECVOL PGA adjusts the recording volume, controlled by register 1Ch or by the
ALC function.
To listen to the PHONE signal, the signal passes through a separate PGA, controlled by register 0Ch.
The signal can be routed into the headphone mixer (for normal phone call operation) and/or the
speaker mixer (for speakerphone operation), but not into the phone mixer (to prevent forming a
feedback loop). When the phone input is not used, the phone-in PGA can be switched off to save
power (see “Power Management” section).
PHONE is biased internally to the reference voltage VREF. Whenever the input is muted or the
device placed into standby mode, the input remains biased to VREF using special anti-thump circuitry
to suppress any audible clicks when changing inputs.
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
0Ch
15
P2H
1
Phone Input
DESCRIPTION
Mute PHONE path to headphone mixer
1: Mute, 0: No mute (ON)
14
P2S
1
Mute PHONE path to speaker mixer
1: Mute, 0: No mute (ON)
4:0
PHONE
01000
PHONE input gain
VOL
(0dB)
00000: +12dB
… (1.5dB steps)
11111: -34.5dB
Table 4 Phone Input Control
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PCBEEP INPUT
Pin 19 (PCBEEP) is a mono, line level input intended for externally generated signal or warning
tones. It is routed directly to the record selector and all three output mixers, without an input amplifier.
The signal gain into each mixer can be independently controlled, with a separate mute bit for each
signal path.
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
0Ah
15
B2H
1
PCBEEP input
DESCRIPTION
Mute PCBEEP path to headphone mixer
1: Mute, 0: No mute (ON)
14:12
B2HVOL
010
PCBEEP to headphone mixer gain
(0dB)
000: +6dB
… (3dB steps)
111: -15dB
11
B2S
1
Mute PCBEEP path to speaker mixer
1: Mute, 0: No mute (ON)
10:8
B2SVOL
010
PCBEEP to speaker mixer gain
(0dB)
000: +6dB
… (3dB steps)
111: -15dB
7
B2P
1
Mute PCBEEP path to phone mixer
1: Mute, 0: No mute (ON)
6:4
B2PVOL
010
PCBEEP to phone mixer gain
(0dB)
000: +6dB
… (3dB steps)
111: -15dB
Table 5 PCBEEP Control
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AUDIO ADC
The WM9712L has a stereo sigma-delta ADC to digitize audio signals. The ADC achieves high quality
audio recording at low power consumption. The ADC sample rate can be controlled by writing to a
control register (see “Variable Rate Audio”). It is independent of the DAC sample rate.
To save power, the left and right ADCs can be separately switched off using the PD11 and PD12 bits,
whereas PR0 disables both ADCs (see “Power Management” section). If only one ADC is running, the
same ADC data appears on both the left and right AC-Link slots.
HIGH PASS FILTER
The WM9712L audio ADC incorporates a digital high-pass filter that eliminates any DC bias from the
ADC output data. The filter is enabled by default. For DC measurements, it can be disabled by writing
a ‘1’ to the HPF bit (register 5Ch, bit 3).
ADC SLOT MAPPING
By default, the output of the left audio ADC appears on slot 3 of the SDATAIN signal (pin 8), and the
right ADC data appears on slot 4. However, the ADC output data can also be sent to other slots, by
setting the ASS (ADC slot select) control bits as shown below.
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
5Ch
1:0
ASS
00
Additional
Function
Control
DESCRIPTION
ADC to slot mapping
00: Left = Slot 3, Right = Slot 4 (default)
01: Left = Slot 7, Right = Slot 8
10: Left = Slot 6, Right = Slot 9
11: Left = Slot 10, Right = Slot 11
3
HPF
0
High-pass filter disable
0: Filter enabled (for audio)
1: Filter disabled (for DC measurements)
Table 6 ADC Control
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RECORD SELECTOR
The record selector determines which input signals are routed into the audio ADC. The left and right
channels can be selected independently. This is useful for recording a phone call: one channel can be
used for the RX signal and the other for the TX signal, so that both sides of the conversation are
digitized.
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
1Ah
14
BOOST
0
Record
Select
DESCRIPTION
20dB Boost
1: Boost ADC input signal by 20dB
0 :No boost
13:12
R2P
11
Record to phone path enable
00: Left ADC and Right ADC to phone mixer
01 : Left ADC to phone mixer
10: Right ADC to phone imixer
11 : Muted
11
R2PBOOST
0
20dB Boost for ADC to phone signal
1: Boost signal by 20dB
0 :No boost
10:8
RECSL
000
Left ADC signal source
000: MIC* (pre-PGA)
001-010: Reserved (do not use this setting)
011: Speaker mix
100: LINEINL (pre-PGA)
101: Headphone Mix (left)
110: Phone Mix
111: PHONE (pre-PGA)
2:0
RECSR
000
Right ADC signal source
000: MIC* (pre-PGA)
001-010: Reserved (do not use this setting)
011: Speaker mix
100: LINEINR (pre-PGA)
101: Headphone Mix (right)
110: Phone Mix
111: PHONE (pre-PGA)
Table 7 Audio Record Selector
Note:
*In stereo mic mode, MIC1 is routed to the left ADC and MIC2 to the right ADC. In all mono mic
modes, the same signal (MIC1, MIC2 or MIC1-MIC2) is routed to both the left and right ADCs.
See “Microphone Input” section for details.
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RECORD GAIN
The amplitude of the signal that enters the audio ADC is controlled by the Record PGA
(Programmable Gain Amplifier). The PGA gain can be programmed either by writing to the Record
Gain register, or by the Automatic Level Control (ALC) circuit (see next section). When the ALC is
enabled, any writes to the Record Gain register have no effect.
Two different gain ranges can be implemented: the standard gain range defined in the AC’97
standard, or an extended gain range with smaller gain steps. The ALC circuit always uses the
extended gain range, as this has been found to result in better sound quality.
The output of the Record PGA can also be mixed into the phone and/or headphone outputs (see
“Audio Mixers”). This makes it possible to use the ALC function for the microphone signal in a
smartphone application.
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
1Ch
15
RMU
1
Record Gain
DESCRIPTION
Mute Audio ADC (both channels)
1: Mute (OFF)
0: No Mute (ON)
14
GRL
0
Gain range select (left)
0: Standard (0 to 22.5dB, 1.5dB step size)
1: Extended (-17.25 to +30dB, 0.75dB steps)
13:8
7
RECVOLL
ZC
000000
0
Record Volume (left)
Standard (GRL=0)
Extended (GRL=1)
XX0000: 0dB
000000: -17.25dB
XX0001: +1.5dB
000001: -16.5dB
… (1.5dB steps)
… (0.75dB steps)
XX1111: +22.5dB
111111: +30dB
Zero Cross Enable
0: Record Gain changes immediately
1: Record Gain changes when signal is zero
or after time-out
6
GRR
0
Gain range select (right)
Similar to GRL
5:0
RECVOLR
000000
Record Volume (right)
Similar to RECVOLL
Table 8 Record Gain Register
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AUTOMATIC LEVEL CONTROL
The WM9712L has an automatic level control that aims to keep a constant recording volume
irrespective of the input signal level. This is achieved by continuously adjusting the PGA gain so that
the signal level at the ADC input remains constant. A digital peak detector monitors the ADC output
and changes the PGA gain if necessary.
input
signal
PGA
gain
signal
after
ALC
ALC
target
level
hold
time
decay
time
attack
time
Figure 3 ALC Operation
The ALC function is enabled using the ALCSEL control bits. When enabled, the recording volume can
be programmed between –6dB and –28.5dB (relative to ADC full scale) using the ALCL register bits.
HLD, DCY and ATK control the hold, decay and attack times, respectively:
Hold time is the time delay between the peak level detected being below target and the PGA gain
n
beginning to ramp up. It can be programmed in power-of-two (2 ) steps, e.g. 2.67ms, 5.33ms,
10.67ms etc. up to 43.7s. Alternatively, the hold time can also be set to zero. The hold time only
applies to gain ramp-up, there is no delay before ramping the gain down when the signal level is
above target.
Decay (Gain Ramp-Up) Time is the time that it takes for the PGA gain to ramp up across 90% of its
range (e.g. from –15B up to 27.75dB). The time it takes for the recording level to return to its target
value therefore depends on both the decay time and on the gain adjustment required. If the gain
adjustment is small, it will be shorter than the decay time. The decay time can be programmed in
n
power-of-two (2 ) steps, from 24ms, 48ms, 96ms, etc. to 24.58s.
Attack (Gain Ramp-Down) Time is the time that it takes for the PGA gain to ramp down across 90%
of its range (e.g. from 27.75dB down to –15B gain). The time it takes for the recording level to return
to its target value therefore depends on both the attack time and on the gain adjustment required. If
the gain adjustment is small, it will be shorter than the attack time. The attack time can be
n
programmed in power-of-two (2 ) steps, from 6ms, 12ms, 24ms, etc. to 6.14s.
When operating in stereo, the peak detector takes the maximum of left and right channel peak values,
and any new gain setting is applied to both left and right PGAs, so that the stereo image is preserved.
However, the ALC function can also be enabled on one channel only. In this case, only one PGA is
controlled by the ALC mechanism, while the other channel runs independently with its PGA gain set
through the control register.
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REGISTER
ADDRESS
BIT
LABEL
62h
15:14
ALCSEL
ALC / Noise
Gate Control
DEFAULT
DESCRIPTION
00
ALC function select
(OFF)
00 = ALC off (PGA gain set by register)
01 = Right channel only
10 = Left channel only
11 = Stereo (PGA registers unused)
Note: Ensure that RECVOLL and RECVOLR
settings (reg. 1Ch) are the same before
entering this mode
13:11
MAXGAIN
111
PGA gain limit for ALC
(+30dB)
111 = +30dB
110 = +24dB
….(6dB steps)
001 = -6dB
000 = -12dB
8
ALCZC
0
ALC Zero Cross enable (overrides ZC bit in
register 1Ch)
0: PGA Gain changes immediately
1: PGA Gain changes when signal is zero or
after time-out
9:10
ZC
TIMEOUT
11
Programmable zero cross timeout
17
11 2 x MCLK period
16
10 2 x MCLK period
15
01 2 x MCLK period
14
00 2 x MCLK period
60h
15:12
ALCL
ALC Control
1011
ALC target – sets signal level at ADC input
(-12dB)
0000 = -28.5dB FS
0001 = -27.0dB FS
… (1.5dB steps)
1110 = -7.5dB FS
1111 = -6dB FS
11:8
HLD
0000
ALC hold time before gain is increased.
(0ms)
0000 = 0ms
0001 = 2.67ms
0010 = 5.33ms
… (time doubles with every step)
1111 = 43.691s
7:4
DCY
0011
ALC decay (gain ramp-up) time
(192ms)
0000 = 24ms
0001 = 48ms
0010 = 96ms
… (time doubles with every step)
1010 or higher = 24.58s
3:0
ATK
0010
ALC attack (gain ramp-down) time
(24ms)
0000 = 6ms
0001 = 12ms
0010 = 24ms
… (time doubles with every step)
1010 or higher = 6.14s
Table 9 ALC Control
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MAXIMUM GAIN
The MAXGAIN register sets the maximum gain value that the PGA can be set to whilst under the
control of the ALC. This has no effect on the PGA when ALC is not enabled.
PEAK LIMITER
To prevent clipping when a large signal occurs just after a period of quiet, the ALC circuit includes a
limiter function. If the ADC input signal exceeds 87.5% of full scale (–1.16dB), the PGA gain is
ramped down at the maximum attack rate (as when ATK = 0000), until the signal level falls below
87.5% of full scale. This function is automatically enabled whenever the ALC is enabled.
(Note: If ATK = 0000, then the limiter makes no difference to the operation of the ALC. It is designed
to prevent clipping when long attack times are used).
NOISE GATE
When the signal is very quiet and consists mainly of noise, the ALC function may cause “noise
pumping”, i.e. loud hissing noise during silence periods. The WM9712L has a noise gate function that
prevents noise pumping by comparing the signal level at the input pins (i.e. before the record PGA)
against a noise gate threshold, NGTH. Provided that the noise gate function is enabled (NGAT = 1),
the noise gate cuts in when:

Signal level at ADC [dB] < NGTH [dB] + PGA gain [dB] + Mic Boost gain [dB]
This is equivalent to:

Signal level at input pin [dB] < NGTH [dB]
The PGA gain is then held constant (preventing it from ramping up as it normally would when the
signal is quiet). If the NGG bit is set, the ADC output is also muted when the noise gate cuts in.
The table below summarises the noise gate control register. The NGTH control bits set the noise gate
threshold with respect to the ADC full-scale range. The threshold is adjusted in 1.5dB steps. Levels
at the extremes of the range may cause inappropriate operation, so care should be taken with set–up
of the function. Note that the noise gate only works in conjunction with the ALC function, and always
operates on the same channel(s) as the ALC (left, right, both, or none).
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
62h
7
NGAT
0
ALC / Noise
Gate Control
DESCRIPTION
Noise gate function enable
1 = enable
0 = disable
5
NGG
0
Noise gate type
0 = PGA gain held constant
1 = mute ADC output
4:0
NGTH(4:0)
00000
Noise gate threshold
00000: -76.5dBFS
00001: -75dBFS
… 1.5 dB steps
11110: -31.5dBFS
11111: -30dBFS
Table 10 Noise Gate Control
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AUDIO DACS
STEREO DAC
The WM9712L has a stereo sigma-delta DAC that achieves high quality audio playback at low power
consumption. Digital tone control, adaptive bass boost and 3-D enhancement functions operate on
the digital audio data before it is passed to the stereo DAC. (Contrary to the AC’97 specification, they
have no effect on analogue input signals or signals played through the auxiliary DAC. Nevertheless,
the ID2 and ID5 bits in the reset register, 00h, are set to ‘1’ to indicate that the WM9712L supports
tone control and bass boost.)
The DAC output has a PGA for volume control. The DAC sample rate can be controlled by writing to a
control register (see “Variable Rate Audio”). It is independent of the ADC sample rate. The left and
right DACs can be separately powered down using the PD13 and PD14 control bits, whereas the PR1
bit disables both DACs (see “Power Management” section).
STEREO DAC VOLUME
The volume of the DAC output signal is controlled by a PGA (Programmable Gain Amplifier). It can be
mixed into the headphone, speaker and phone output paths (see “Audio Mixers”).
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
18h
15
D2H
1
DAC
Volume
DESCRIPTION
Mute DAC path to headphone mixer
1: Mute, 0: No mute (ON)
14
D2S
1
Mute DAC path to speaker mixer
1: Mute, 0: No mute (ON)
13
D2P
1
Mute DAC path to phone mixer
1: Mute, 0: No mute (ON)
12:8
DACL
01000
Left DAC Volume
VOL
(0dB)
00000: +12dB
… (1.5dB steps)
11111: -34.5dB
4:0
5Ch
Additional
Functions
(1)
15
DACR
01000
Right DAC Volume
VOL
(0dB)
similar to DACLVOL
AMUTE
0
Read-only bit to indicate auto-muting
1: DAC auto-muted
0: DAC not muted
7
AMEN
0
DAC Auto-Mute Enable
1: Automatically mutes analogue output of
stereo DAC if digital input is zero
0: Auto-mute OFF
Table 11 Stereo DAC Volume Control
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TONE CONTROL / BASS BOOST
The WM9712L provides separate controls for bass and treble with programmable gains and filter
characteristics. This function operates on digital audio data before it is passed to the audio DACs.
Bass control can take two different forms:

Linear bass control: bass signals are amplified or attenuated by a user programmable
gain. This is independent of signal volume, and very high bass gains on loud signals may
lead to signal clipping.

Adaptive bass boost: The bass volume is amplified by a variable gain. When the bass
volume is low, it is boosted more than when the bass volume is high. This method is
recommended because it prevents clipping, and usually sounds more pleasant to the
human ear.
Treble control applies a user programmable gain, without any adaptive boost function.
Treble, linear bass and 3D enhancement can all produce signals that exceed full-scale. In order to
avoid limiting under these conditions, it is recommended to set the DAT bit to attenuate the digital
input signal by 6dB. The gain at the outputs should be increased by 6dB to compensate for the
attenuation. Cut-only tone adjustment and adaptive bass boost cannot produce signals above fullscale and therefore do not require the DAT bit to be set.
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
08h
15
BB
0
DAC Tone
Control
DESCRIPTION
Bass Mode
0 = Linear bass control
1 = Adaptive bass boost
12
BC
0
Bass Cut-off Frequency
0 = Low (130Hz at 48kHz sampling)
1 = High (200Hz at 48kHz sampling)
11:8
6
BASS
DAT
1111
(OFF)
0
Bass Intensity
Code
BB=0
BB=1
0000
+9dB
15 (max)
0001
+9dB
14
0010
+7.5dB
13
…
(1.5dB steps)
…
0111
0dB
8
…
(1.5dB steps)
…
1011-1101
-6dB
4-2
1110
-6dB
1 (min)
1111
Bypass (OFF)
-6dB attenuation
0 = Off
1 = On
4
TC
0
Treble Cut-off Frequency
0 = High (8kHz at 48kHz sampling)
1 = Low (4kHz at 48kHz sampling)
3:0
TRBL
1111
(Disabled)
Treble Intensity
0000 or 0001 = +9dB
0010 = +7.5dB
… (1.5dB steps)
1011 to 1110 = -6dB
1111 = Treble Control Disabled
Table 12 DAC Tone Control
Note:
1.
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All cut-off frequencies change proportionally with the DAC sample rate.
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3D STEREO ENHANCEMENT
The 3D stereo enhancement function artificially increases the separation between the left and right
channels by amplifying the (L-R) difference signal in the frequency range where the human ear is
sensitive to directionality. The programmable 3D depth setting controls the degree of stereo
expansion introduced by the function. Additionally, the upper and lower limits of the frequency range
used for 3D enhancement can be selected using the 3DFILT control bits.
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
20h
13
3DE
0
(disabled)
3D enhancement enable
5
3DLC
0
General
Purpose
22h
DAC 3D
Control
Lower Cut-off Frequency
0 = Low (200Hz at 48kHz sampling)
1 = High (500Hz at 48kHz sampling)
4
3DUC
0
Upper Cut-off Frequency
0 = High (2.2kHz at 48kHz sampling)
1 = Low (1.5kHz at 48kHz sampling)
3:0
3DDEPTH
0000
3D Depth
0000: 0% (minimum 3D effect)
0001: 6.67%
…
1110: 93.3%
1111: 100% (maximum)
Table 13 Stereo Enhancement Control
Note:
1.
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All cut-off frequencies change proportionally with the DAC sample rate.
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AUXILIARY DAC
AUXDAC is a simple 12-bit mono DAC. It can be used to generate DC signals (with the numeric input
written into a control register), or AC signals such as telephone-quality ring tones or system beeps
(with the input signal supplied through an AC-Link slot). In AC mode (XSLE = 1), the input data is
binary offset coded; in DC mode (XSLE = 0), there is no offset.
The analogue output of AUXDAC is routed directly into the output mixers. The signal gain into each
mixer can be adjusted at the mixer inputs using control register 12h. In slot mode (XSLE = 1), the
AUXDAC also supports variable sample rates (See “Variable Rate Audio” section).
When the auxiliary DAC is not used, it can be powered down by setting AXE = 0. This is also the
default setting.
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
64h
15
XSLE
0
AUXDAC input selection
AUDAC Input
Control
0: from AUXDACVAL (for DC signals)
1: from AC-Link slot selected by
AUXDACSLT (for AC signals)
14:12
AUXDAC
000
SLT
AUXDAC Input Selection
000 – Slot 5, bits 8-19 (with XSLE=1)
001 – Slot 6, bits 8-19 (with XSLE=1)
010 – Slot 7, bits 8-19 (with XSLE=1)
011 – Slot 8, bits 8-19 (with XSLE=1)
100 – Slot 9, bits 8-19 (with XSLE=1)
101 – Slot 10, bits 8-19 (with XSLE=1)
110 – Slot 11, bits 8-19 (with XSLE=1)
111 – RESERVED (do not use)
11:0
AUXDAC
000h
VAL
AUXDAC Digital Input (with XSLE=0)
000h: minimum
FFFh: full-scale
12h
15
A2H
1
Mute AUXDAC path to headphone
mixer
14:12
A2HVOL
010
AUXDAC to headphone mixer gain
(0dB)
000: +6dB
AUXDAC Output
Control
1: Mute, 0: No mute (ON)
… (3dB steps)
111: -15dB
11
A2S
1
Mute AUXDAC path to speaker mixer
1: Mute, 0: No mute (ON)
10:8
A2SVOL
010
AUXDAC to speaker mixer gain
(0dB)
000: +6dB
… (3dB steps)
111: -15dB
7
A2P
1
Mute AUXDAC path to phone mixer
1: Mute, 0: No mute (ON)
6:4
A2PVOL
010
AUXDAC to phone mixer gain
(0dB)
000: +6dB
… (3dB steps)
111: -15dB
0
AXE
0
0: AUXDAC off
1: AUXDAC enabled
Table 14 AUXDAC Control
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ANALOGUE AUDIO OUTPUTS
The following sections give an overview of the analogue audio output pins. For more information on
recommended external components, please refer to the “Applications Information” section.
HEADPHONE OUTPUTS – HPOUTL AND HPOUTR
The HPOUTL and HPOUTR (pins 39 and 41) are designed to drive a 16 or 32 headphone or a line
output. They can also be used as line-out pins. The output signal is produced by the headphone
mixer.
The signal volume on HPOUTL and HPOUTR can be independently adjusted under software control
by writing to register 04h. When HPOUTL and HPOUTR are not used, the output drivers can be
disabled to save power (see “Power Management” section). Both pins remain at the same DC level
(the reference voltage VREF) when they are disabled, so that no click noise is produced.
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
04h
15
MUTE
1
HPOUTL /
HPOUTR
Volume
DESCRIPTION
Mute HPOUTL and HPOUTR
1: Mute (OFF)
0: No Mute (ON)
13:8
HPOUTLVOL
000000
HPOUTL Volume
(0dB)
000000: 0dB (maximum)
000001: -1.5dB
… (1.5dB steps)
011111: -46.5dB
1xxxxx: -46.5dB
7
ZC
0
Zero Cross Enable
0: Change gain immediately
1: Change gain only on zero crossings,
or after time-out
5:0
HPOUTRVOL
00000
HPOUTR Volume
(0dB)
Similar to HPOUTLVOL
Table 15 HPOUTL / HPOUTR Control
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EAR SPEAKER OUTPUT – OUT3
Pin 37 (OUT3) has a buffer that can drive load impedances down to 16. It can be used to:

Drive an ear speaker (phone receiver). The speaker can be connected differentially
between OUT3 and HPOUTL, or in single-ended configuration (OUT3 to HPGND). The
ear speaker output is produced by the headphone mixer. The right signal must be
inverted (OUT3INV = 1), so that the left and right channel are mixed to mono in the
speaker [L–(-R) = L+R].

Eliminate the DC blocking capacitors on HPOUTL and HPOUTR. In this configuration,
OUT3 produces a buffered midrail voltage (AVDD/2) and is connected to the headphone
socket’s ground pin (see “Applications Information”)
Produce the inverse of the MONOOUT signal, for a differential mono output.

Note: OUT3 can only handle one of the above functions at any given time.
REGISTER
ADDRESS
BIT
LABEL
DEFAULT DESCRIPTION
16h
15
MUTE
1
OUT3
Mute OUT3
1: Mute (Buffer OFF)
Control
0: No Mute (Buffer ON)
10:9
OUT3
SRC
00
Source of OUT3 signal
00
inverse of HPOUTR
(for BTL ear speaker)
01
VREF (for capless headphone drive)
10
mono mix of both headphone channels
(for single-ended ear speaker)
11
inverse of MONOOUT
(for differential mono output)
7
ZC
0
Zero Cross Enable
0: Change gain immediately
1: Change gain only on zero crossings, or after
time-out
5:0
OUT3
VOL
000000
OUT3 Volume
(0dB)
000000: 0dB (maximum)
000001: -1.5dB
… (1.5dB steps)
011111: -46.5dB
1xxxxx: -46.5dB
Table 16 OUT3 Control
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LOUDSPEAKER OUTPUTS – LOUT2 AND ROUT2
The LOUT2 and ROUT2 outputs are designed to differentially drive an 8 mono speaker. They can
also be used as a stereo line-out or headphone output.
For speaker drive, the LOUT2 signal must be inverted (INV = 1), so that the left and right channel are
added up in the speaker [R–(-L) = R+L].
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
02h
15
MUTE
1
Mute LOUT2 and ROUT2
LOUT2/ROUT2
1: Mute (OFF)
Volume
0: No Mute (ON)
13:8
LOUT2VOL
00000
LOUT2 Volume
(0dB)
000000: 0dB (maximum)
000001: -1.5dB
… (1.5dB steps)
011111: -46.5dB
1xxxxx: -46.5dB
7
ZC
0
Zero Cross Enable
0: Change gain immediately
1: Change gain only on zero crossings,
or after time-out
6
INV
0
LOUT2 Invert
0 = No Inversion (0 phase shift)
1 = Signal inverted (180 phase shift)
5:0
16h
8
ROUT2VOL
SRC
00000
ROUT2 Volume
(0dB)
Similar to LOUT2VOL
0
Source of LOUT2/ROUT2 signals
0: speaker mixer (for BTL speaker)
1: headphone mixer (for stereo output)
Table 17 LOUT2 / ROUT2 Control
Note:
1.
w
For BTL speaker drive, it is recommended that LOUT2VOL = ROUT2VOL.
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PHONE OUTPUT (MONOOUT)
The MONOOUT output (pin 33) is intended for connection to the TX side of a wireless chipset. The
signal is generated in a dedicated mono mixer; it is not necessarily a mono mix of the stereo outputs
HPOUTL/R or LOUT2/ROUT2 (see “Audio Mixers” section).
The MONOOUT volume can be controlled by writing to register 06h. When MONOOUT is not used,
the output buffer can be disabled to save power (see “Power Management” section). The MONOOUT
pin remains at the same DC level (the reference voltage on the VREF pin), so that no click noise is
produced when muting or un-muting.
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
06h
15
MUTE
1
DESCRIPTION
Mute MONOOUT
MONOOUT
1: Mute
Volume
0: No Mute
7
ZC
0
Zero Cross Enable
0: Change gain immediately
1: Change gain only on zero crossings,
or after time-out
4:0
MONOOUT
VOL
00000
MONOOUT Volume
(0dB)
00000: 0dB (maximum)
00001: -1.5dB
… (1.5dB steps)
11111: -46.5dB
Table 18 MONOOUT Control
THERMAL SENSOR
The speaker and headphone outputs can drive very large currents. To protect the WM9712L from
becoming too hot, a thermal sensor has been built in. If the chip temperature reaches approximately
150C, and the ENT bit is set, the WM9712L deasserts GPIO bit 11 in register 54h, a virtual GPIO
that can be set up to generate an interrupt to the CPU (see “GPIO and Interrupt Control” section).
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
5Ch
2
ENT
0
DESCRIPTION
Enable thermal sensor
0: Disabled
1: Enabled
54h
11
TI
1
Thermal sensor (virtual GPIO)
1: Temperature below 150C
0: Temperature above 150C
See also “GPIO and Interrupt Control” section.
Table 19 Thermal Cutout Control
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JACK INSERTION AND AUTO-SWITCHING
In a phone application, a BTL ear speaker may be connected across OUT3 and HPOUTL, and a
stereo headphone on HPOUTL and HPOUTR. Typically, only one of these two output devices is used
at any given time: when no headphone is plugged in, the BTL ear speaker is active, otherwise the
headphone is used.
The presence of a headphone can be detected using GPIO1 (pin 44) and an external pull-up resistor
(see “Applications Information” section for a circuit diagram). When the jack is inserted GPIO1 is
pulled low by a switch on the socket. When the jack is removed GPIO1 is pulled high by a resistor. If
the JIEN bit is set, the WM9712L automatically switches between headphone and ear speaker, as
shown below.
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
58h
Additional
Functional
Control
12
JIEN
0
Jack Insert Enable – Takes output of GPIO1
logic
11
FRC
0
Force Ear Speaker Mode
See table below
1
0
0
Jack insert detection enabled,
headphone plugged in
1
X
1
Jack insert detection enabled,
headphone not plugged in
0
1
X
Force Ear Speaker Mode
Set by
reg.
24h
and
26h
1
1
X
Invalid; do not use this setting
STATE
HPOUTL/
HPOUTR
OUT3
VOLUME
HPOUTR
VOLUME
VOLUME
Set by
reg.
16h
Set by reg. 24h and 26h
Jack insert detection disabled
(headphone and ear speaker
can be used at the same
time)
Set by reg. 16h
X
Set by reg. 04h
0
Disabled
Set by
reg.
24h
and
26h
0
Set by reg. 04h
STATE
GPIO1 MODE DESCRIPTION
OUT3
JIEN FRC
HPOUTL
Table 20 Jack Insertion / Auto-Switching (1)
Table 21 Jack Insertion / Auto-Switching (2)
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DIGITAL AUDIO (SPDIF) OUTPUT
The WM9712L supports the SPDIF standard using pin 47 as its output. Note that pin 47 can also be
used as a GPIO pin. The GE5 bit (register 56h, bit 5) selects between GPIO and SPDIF functionality
(see “GPIO and Interrupt control” section).
Register 3Ah is a read/write register that controls SPDIF functionality and manages bit fields
propagated as channel status (or sub-frame in the V case). With the exception of V, this register
should only be written to when the SPDIF transmitter is disabled (SPDIF bit in register 2Ah is ‘0’).
Once the desired values have been written to this register, the contents should be read back to
ensure that the sample rate in particular is supported, then SPDIF validity bit SPCV in register 2Ah
should be read to ensure the desired configuration is valid. Only then should the SPDIF enable bit in
register 2Ah be set. This ensures that control and status information start up correctly at the
beginning of SPDIF transmission.
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
2Ah
10
SPCV
0
SPDIF validity bit (read-only)
Extended
Audio
5:4
SPSA
01
SPDIF slot assignment (ADCO = 0)
00: Slots 3, 4
01: Slots 6, 9
10: Slots 7, 8
11: Slots 10, 11
2
SEN
0
SPDIF output enable
1 = enabled, 0 = disabled
3Ah
15
V
0
SPDIF
Control
Register
Validity bit; ‘0’ indicates frame valid, ‘1’
indicates frame not valid
14
DRS
0
Indicates that the WM9712L does not support
double rate SPDIF output (read-only)
13:12
SPSR
10
Indicates that the WM9712L only supports
48kHz sampling on the SPDIF output (readonly)
11
L
0
Generation level; programmed as required by
user
10:4
CC
0000000
Category code; programmed as required by
user
3
PRE
0
Pre-emphasis; ‘0’ indicates no pre-emphasis,
‘1’ indicates 50/15us pre-emphasis
2
COPY
0
Copyright; ‘0’ indicates copyright is not
asserted, ‘1’ indicates copyright
1
AUDIB
0
Non-audio; ‘0’ indicates data is PCM, ‘1’
indicates non-PCM format (e.g. DD or DTS)
0
PRO
0
Professional; ‘0’ indicates consumer, ‘1’
indicates professional
4
ADCO
0
Source of SPDIF data
5Ch
Additional
Function
Control
0: SPDIF data comes from SDATAOUT (pin
5), slot selected by SPSA
1: SPDIF data comes from audio ADC
Table 22 SPDIF Output Control
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AUDIO MIXERS
MIXER OVERVIEW
The WM9712L has three separate low-power audio mixers to cover all audio functions required by
smartphones, PDAs and handheld computers. The diagram below shows the routing of the analogue
audio signals into the mixers. The numbers at the mixer inputs refer to the control register bits that
control the volume and muting for that particular signal.
0Eh [7]
MICL
MICR
DIFF /
STEREO/
MONO
0Eh [12:8,4:0]
(Reg 20h)
0/20
dB
10h [12:8,4:0]
LINE_IN
PCBEEP
0Eh [14,13]
18h [13]
1Ah [13:11]
10h [13]
12h [7:4]
0Ah [7:4]
OUT3VOL
(Reg 16h)
OUT3SRC
(Reg 16h)
VREF
0Ch [4:0]
PHONE_IN
STEREO
M RECORD
U
X SELECT
M
U
X
MONOOUT
0Ch [15]
10h [15]
14h [11:7]
18h [15]
14h [15:12]
0Ah [15:12]
12h [15:12]
18h [12:8,4:0]
DAC
PHONE MIX
MONOOUT
(PHONE TX)
PHONE
MIX
1Ch / ALC
OUT3
ear
speaker
HEAD
PHONE/
EAR
SPEAKER
MIX
HPOUTL
HPOUTR
HPVOL
(Reg 04h)
Stereo
headphone /
headset
INV
(Reg 02h)
HEADPHONE MIX
10h [14]
18h [14]
12h [11:8]
0Ah [11:8]
0Ch [14]
BACK SPKR MIX
AUX
DAC
(12-BIT)
0/20
dB
1Ah [14]
-1
BACK
SPEAKER
MIX
STEREO
ADC
LOUT2
M
U
X
loud
speaker
OUT2VOL
(Reg 02h)
SRC
(Reg 16h)
ROUT2
Figure 4 Audio Mixer Overview
HEADPHONE MIXER
The headphone mixer drives the HPOUTL and HPOUTR outputs. It also drives OUT3, if this pin is
connected to an ear speaker (phone receiver). The following signals can be mixed into the
headphone path:

PHONE (controlled by register 0Ch, see “Audio Inputs”)


LINE_IN (controlled by register 10h, see “Audio Inputs”)
the output of the Record PGA (see “Audio ADC”, “Record Gain”)


the stereo DAC signal (controlled by register 18h, see “Audio DACs”)
the MIC signal (controlled by register 0Eh, see “Audio Inputs”)


PC_BEEP (controlled by register 0Ah, see “Audio Inputs”)
the AUXDAC signal (controlled by register 12h, see “Auxiliary DAC”)
In a typical smartphone application, the headphone signal is a mix of PHONE and sidetone (for phone
calls) and the stereo DAC signal (for music playback).
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SPEAKER MIXER
The speaker mixer drives the LOUT2 and ROUT2 output. The following signals can be mixed into the
speaker path:

PHONE (controlled by register 0Ch, see “Audio Inputs”)


LINE_IN (controlled by register 10h, see “Audio Inputs”)
the stereo DAC signal (controlled by register 18h, see “Audio DACs”)


PC_BEEP (controlled by register 0Ah, see “Audio Inputs”)
the AUXDAC signal (controlled by register 12h, see “Auxiliary DAC”)
In a typical smartphone application, the speaker signal is a mix of AUXDAC (for system alerts or ring
tone playback), PHONE (for speakerphone function), and PC_BEEP (for externally generated ring
tones).
MONO MIXER
The mono mixer drives the MONOOUT pin. The following signals can be mixed into MONOOUT:

LINE_IN (controlled by register 10h, see “Audio Inputs”)


the output of the Record PGA (see “Audio ADC”, “Record Gain”)
the stereo DAC signal (controlled by register 18h, see “Audio DACs”)


the MIC signal (controlled by register 10h, see “Audio Inputs”)
PC_BEEP (controlled by register 0Ah, see “Audio Inputs”)

the AUXDAC signal (controlled by register 12h, see “Auxiliary DAC”)
In a typical smartphone application, the MONOOUT signal is a mix of the amplified microphone signal
(possibly with Automatic Gain Control) and (if enabled) an audio playback signal from the stereo DAC
or the auxiliary DAC.
SIDE TONE CONTROL
The side tone path is into the headphone mixer and is either from the MIC or ALC path (with no 20dB
boost)
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
14h
15
STM
1
MIC side tone select
Sidetone
0: selected
Control
1 : not selected (path muted)
14:12
STVOL
010
MIC Sidetone volume
(0dB)
000 : +6dB (max.)
001: +3dB
… (3dB steps)
111 : -15dB (min.)
11:10
ALCM
11
ALC side tone select
11: mute
10: mono – left
01: mono – right
00: stereo
9:7
ALCVOL
010
ALC Sidetone volume
(0dB)
Similar to STVOL
Table 23 Side Tone Control
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VARIABLE RATE AUDIO / SAMPLE RATE CONVERSION
By using an AC’97 Rev2.2 compliant audio interface, the WM9712L can record and playback at all
commonly used audio sample rates, and offer full split-rate support (i.e. the DAC, ADC and AUXDAC
sample rates are completely independent of each other – any combination is possible).
The default sample rate is 48kHz. If the VRA bit in register 2Ah is set and the appropriate block is
enabled, then other sample rates can be selected by writing to registers 2Ch, 32h and 2Eh. The ACLink continues to run at 48k frames per second irrespective of the sample rate selected. However, if
the sample rate is less than 48kHz, then some frames do not carry an audio sample.
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
2Ah
0
VRA
0 (OFF)
Extended
Audio
Stat/Ctrl
2Ch
DESCRIPTION
Variable Rate Audio
0: OFF (DAC and ADC run at 48kHz)
1: ON (sample rates determined by
registers 2Ch, 2Eh and 32h)
15:0
DACSR
Audio DAC
Sample Rate
BB80h
Audio DAC sample rate
(48kHz)
1F40h: 8kHz
2B11h: 11.025kHz
2EE0h: 12kHz
3E80h: 16kHz
5622h: 22.05kHz
5DC0h: 24kHz
7D00h: 32kHz
AC44h: 44.1kHz
BB80h: 48kHz
Any other value defaults to the nearest
supported sample rate
32h
15:0
ADCSR
Audio ADC
Sample Rate
2Eh
AUXDAC
Sample Rate
15:0
AUXDA
CSR
BB80h
Audio ADC sample rate
(48kHz)
similar to DACSR
BB80h
(48kHz)
AUXDAC sample rate
similar to DACSR
Table 24 Audio Sample Rate Control
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TOUCHPANEL INTERFACE
The WM9712L includes a touchpanel driver and digitiser circuit for use with 4-wire or 5-wire resistive
touchpanels. The following functions are implemented:


X co-ordinate measurement
Y co-ordinate measurement


Pen down detection, with programmable sensitivity
Touch pressure measurement (4-wire touchpanel only)

Auxiliary measurement from COMP1/AUX1 (pin 29), COMP2/AUX2 (pin 30), BMON/AUX3
(pin 31), or WIPER/AUX4 (pin 12)
The touchpanel digitiser uses a very low power, 12-bit successive approximation type ADC. The
same ADC can also be used for battery and auxiliary measurements (see the “Battery Alarm and
Battery Measurement” and “Auxiliary ADC Inputs” sections).
An on-chip switch matrix connects each touchpanel terminal to the supply voltage TPVDD, to ground
(TPGND), or to the ADC input, as required.
RPU
IP
zero power
comparator
PEN
DOWN
SAR
ADC
10K
X+/BR (14)
X-/TL (16)
Y+/TR (15)
Y-/BL (17)
WIPER/AUX4 (12)
AUX1 (29)
AUX2 (30)
AUX3/BMON (31)
TPGND
TPVDD
20K
Figure 5 Touchpanel Switch Matrix
PRINCIPLE OF OPERATION - FOUR-WIRE TOUCHPANEL
Four-wire touchpanels are connected to the WM9712L as follows:
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
Right side contact = X+ (pin 14)


Left side contact = X- (pin 16)
Top side contact = Y+ (pin 15)

Bottom side contact = Y- (pin 17)
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The principle of operation is illustrated below (Note: the illustrations assume that the top plate is used
for X and the bottom plate for Y measurements, although the reverse is also possible).
pen / finger
Y+ (15)
WM9712
VM = (VREF+ - VREF-) RX- / (RX- + RX+)
= proportional to X position
RXRY-
RY+
RX+
TPVDD
X+
(14)
VREF+
VM
ADC
Y- (17)
VREF-
X- (16)
TPGND
Figure 6 X Co-ordinate Measurement on 4-wire Touchpanel
For an X co-ordinate measurement, the X+ pin is internally switched to VDD and X- to GND. The X
plate becomes a potential divider, and the voltage at the point of contact is proportional to its X coordinate. This voltage is measured on the Y+ and Y- pins, which carry no current (hence there is no
voltage drop in RY+ or RY-).
Due to the ratiometric measurement method, the supply voltage does not affect measurement
accuracy. The voltage references VREF+ and VREF- are taken from after the matrix switches, so that
any voltage drop in these switches has no effect on the ADC measurement.
pen / finger
Y+ (15)
TPVDD
VREF+
RXRY-
RY+
RX+
VM
X+
(14)
ADC
WM9712
VREF-
Y- (17)
X- (16)
TPGND
VM = (VREF+ - VREF-) RY- / (RY- + RY+)
= proportional to Y position
Figure 7 Y Co-ordinate Measurement on 4-wire Touchpanel
Y co-ordinate measurements are similar to X co-ordinate measurements, with the X and Y plates
interchanged.
pen / finger
Y+ (15)
TPVDD
RPU
RXRY-
RY+
RX+
PEN
DOWN
X+
(14)
zero power
comparator
Y- (17)
TPGND
X- (16)
WM9712
Figure 8 Pen Down Detection on 4-wire Touchpanel
Pen down detection uses a zero power comparator (effectively a CMOS logic gate) with an internal,
programmable pull-up resistor RPU that controls pen-down sensitivity. Increasing RPU makes the
touchpanel less sensitive to touch, while lowering RPU makes it more sensitive.
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When the touchpanel is not being touched, no current flows in the circuit, and the PENDOWN signal
is low. When the panel is touched with a pen or finger, current flows through RPU and the panel, and
the comparator output goes high.
The PENDOWN signal can be read from bit 15 in register 7Ah (labeled PNDN). It can also be
observed on pin 46 (GPIO3 / PENDOWN), if the pin is not used for GPIO (GE3=0). Additionally,
PENDOWN is passed to the GPIO logic block (register 54h, bit 13), where it can generate CPU
interrupts, and / or to wake up the WM9712L from sleep mode (see “GPIO and Interrupt Control”
section).
pen / finger
Y+ (15)
TPVDD
IP
RXRY-
VY- - VX+ = IP RC
= proportional to contact resistance
RY+
RX+
X+
(14)
ADC
Y- (17)
X- (16)
TPGND
WM9712
Figure 9 Touch Pressure Measurement on 4-wire Touchpanel
Touch pressure can be determined indirectly by measuring the contact resistance RC between the top
and bottom plates. RC decreases as the touch pressure on the panel increases. The WM9712L
measures RC by sending a constant current IP through the touchpanel and measuring the potential on
each plate. The two values are subtracted in the digital domain to obtain the potential difference,
which is proportional to RC.
To suit different types of touchpanels, the magnitude of IP can be set to either 400A or 200A using
the PIL control bit.
PRINCIPLE OF OPERATION - FIVE-WIRE TOUCHPANEL
Five-wire touchpanels are connected to the WM9712Las follows:

Top sheet contact = WIPER/AUX4 (pin 12)


Top left corner of bottom sheet = TL (pin 16)
Top right corner of bottom sheet = TR (pin 15)


Bottom left corner of bottom sheet = BL (pin 17)
Bottom right corner of bottom sheet = BR (pin 14)
VREF+
WIPER (12)
TR (15)
VM
ADC
VREFTPVDD
WM9712
VM = proportional to X position
BR (14)
BL (17)
TL (16)
TPVDD
TPGND
TPGND
Figure 10 X Co-ordinate Measurement on 5-wire Touchpanel
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For an X co-ordinate measurement, the top left and bottom left corners of the touchpanel are
grounded internally to the WM9712, while the top right and bottom right contacts are connected to
TPVDD. The bottom plate becomes a potential divider with a voltage gradient in the X direction. The
voltage at the point of contact is proportional to its X co-ordinate. This voltage is measured on the
TOP pin and converted to a digital value by the ADC.
Due to the ratiometric measurement method, the supply voltage does not affect measurement
accuracy. The voltage references VREF+ and VREF- are taken from after the matrix switches, so that
any voltage drop in these switches has no effect on the ADC measurement.
VREF+
WIPER (12)
VM
ADC
VREF-
TR (15)
TPVDD
WM9712
VM = proportional to Y position
BR (14)
TPGND
BL (17)
TPGND
TL (16)
TPVDD
Figure 11 Y Co-ordinate Measurement on 5-wire Touchpanel
Y co-ordinate measurements are similar to Y co-ordinate measurements. However, the voltage
gradient on the bottom plate is in the Y direction instead of the X direction. This is achieved by
grounding the bottom left and bottom right corners of the touchpanel, and connecting the top left and
top right contacts to TPVDD.
RPU
VDD
WIPER (12)
zero power
comparator
PEN
DOWN
TR (15)
TPGND
WM9712
BR (14)
BL (17)
TL (16)
TPGND
TPGND
TPGND
Figure 12 Pen Down Detection on 5-wire Touchpanel
Pen down detection works in a similar fashion for both 4-wire and 5-wire touchpanels (see Four-Wire
Touchpanel Operation). On a 5-wire touchpanel, all four contacts of the bottom plate are grounded,
and the top plate contact is connected to the internal programmable pull-up resistor, RPU.
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CONTROLLING THE TOUCHPANEL DIGITISER
All touchpanel functions are accessed and controlled through the AC-Link interface.
PHYSICAL CHARACTERISTICS
The physical characteristics of the touchpanel interface are controlled through register 78, as shown
below.
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
78h
12
45W
0 (4-wire)
DESCRIPTION
Touchpanel Type Selection
0: 4-wire
1: 5-wire
0:5
RPU
000001
Internal Pull-up resistor for Pen Detection
(64k)
000000: RESERVED (do not use this setting)
000001: RPU/1 = TYP 64k (most sensitive)
000010: RPU /2 = TYP 32k
… (pull-up = RPU / binary value of RPU)
(Refer to page 9 for RPU specification)
8
PIL
0 (200A)
Current used for pressure measurement
0: IP = 200A
1: IP = 400A
Table 25 Touchpanel Digitiser Control (Physical Characteristics)
POWER MANAGEMENT
To save power, the touchpanel digitiser and the pen-down detector can be independently disabled
when they are not used. The power consumption of the pen-down detector is normally negligible,
except when the pen is down.
The state of the digitiser and pen down detector is controlled by the following bits.
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
78h
15:14
PRP
00
DESCRIPTION
Pen ADC/AUX ADC enable
00 – Pen digitiser off, pen detect off, no
wake-up on pen down (default)
01 – Pen digitiser powered off, pen detect
enabled, touchpanel digitiser wakes up
(changes to state 11) on pen-down
10 – Pen digitiser off, pen detect enabled, no
wake-up on pen down
11 – Pen digitiser and pen detect enabled
13
RPR
0
Wake-up on pen-down mode
0: Wake-up the AC-Link only (hold SDATAIN
high until controller sends warm reset or cold
reset)
1: Wake-up the WM9712L without waiting for
a reset signal from the controller
Table 26 Touchpanel Digitiser Control (Power Management)
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INITIATION OF MEASUREMENTS
The WM9712L touchpanel interface supports both polling routines and DMA (direct memory access)
to control the flow of data from the touchpanel ADC to the host CPU.
In a polling routine, the CPU starts each measurement individually by writing to the POLL bit (register
76h, bit 15). This bit automatically resets itself when the measurement is completed.
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
76h
10
CTC
0
0: Polling mode
15
POLL
0
Writing “1” initiates a measurement
9:8
CR
00
Continuous mode rate (DEL ≠ 1111)
1: Continuous mode (for DMA)
00: 93.75 Hz (every 512 AC-Link frames)
01: 187.5 Hz (every 256 AC-Link frames)
10: 375Hz (every 128 AC-Link frames)
11: 750Hz (every 64 AC-Link frames)
Continuous mode rate (DEL = 1111)
00: 8 kHz (every six AC-Link frames)
01: 12 kHz (every four AC-Link frames)
10: 24 kHz (every other AC-Link frame)
11: 48 kHz (every AC-Link frame)
78h
11
PDEN
0
0: measure regardless of pen status
1: measure only when pen is down (when
CTC=0 and POLL=1, measurement is
delayed until pen-down; when CTC=1,
measurements are stopped on pen-up)
Table 27 Touchpanel Digitiser Control (Initiation of Measurements)
In continuous mode (CTC = 1), the WM9712L autonomously initiates measurements at the rate set by
CR, and supplies the measured data to the CPU on one of the unused AC’97 time slots. DMAenabled CPUs can write the data directly into a FIFO without any intervention by the CPU core. This
reduces CPU loading and speeds up the execution of user programs in handheld systems.
Note that the measurement frequency in continuous mode is also affected by the DEL bits (see
“Touchpanel Settling Time”). The faster rates achieved when DEL = 1111 may be useful when the
ADC is used for auxiliary measurements.
MEASUREMENT TYPES
The ADCSEL control bits determine which type of measurement is performed (see below).
REGISTER
ADDRESS
BIT
LABEL
DEFAULT DESCRIPTION
76h
14:12
ADCSEL
000
Measurement Type (ADC Input Selector)
000: No measurement
001: X co-ordinate measurement
010: Y co-ordinate measurement
011: Pressure measurement
100: COMP1/AUX1 measurement (pin 29)
101: COMP2/AUX2 measurement (pin 30)
110: BMON/AUX3 measurement (pin 31)
111: WIPER/AUX4 measurement (pin 12)
11
COO
0
Enable co-ordinate mode
0: Single measurement according to ADCSEL
1: X, then Y, then additional measurement
indicated by ADCSEL
Table 28 Touchpanel Digitiser Control (Measurement Types)
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When COO is ‘0’, the WM9712L performs one type of measurement once (in polling mode) or
continuously (in continuous mode).
The co-ordinate mode (COO = ‘1’) makes it easier to obtain co-ordinate pairs rather than single coordinates. In polling-coordinate mode (CTC = ‘0’, COO = ‘1’), the WM9712L performs an X
measurement, followed by a Y measurement, followed by an additional measurement determined by
ADCSEL, then stops. In continuous-coordinate mode (CTC = ‘1’, COO = ‘1’), the WM9712L
continuously repeats a sequence consisting of an X-co-ordinate measurement, followed by a Y coordinate measurement, followed by an additional measurement determined by ADCSEL (if ADCSEL =
000, the sequence is XYXYXY… only).
DATA READBACK
The output data word of the touchpanel interface consists of three parts:

Pen Status (1 bit) – this is also passed to the GPIO logic block, which can be
programmed to generate an interrupt and/or wake up the WM9712L on pen down (see
GPIO and Interrupt Control).
Output data from the touchpanel ADC (12 bits)


ADCSRC: 3 additional bits that indicate the source of the ADC data. With COO = ‘0’,
ADCSRC echoes ADCSEL. However, in co-ordinate mode (COO = ‘1’), the WM9712L
schedules different types of measurements autonomously and sets the ADCSRC bits
accordingly (see “Measurement Types”).
This data is stored in register 7Ah, and can be retrieved by reading the register in the usual manner
(see AC-Link Interface section). Additionally, the data can also be passed to the controller on one of
the AC-Link time slots not used for audio functions.
If the data is being read back using the polling method, there are several ways to determine when a
measurement has finished:


Reading back the POLL bit. If it has been reset to ‘0’, then the measurement has finished.
By monitoring the ADA signal, see GPIO and interrupt section

Reading back 7Ah until the new data appears
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
7Ah
15
PNDN
0
or
AC-Link slot
selected by
SLT
DESCRIPTION
Pen status (read-only)
0: Pen Up
1: Pen Down
14:12
ADCSRC
000
Touchpanel ADC Source
000: No measurement
001: X co-ordinate measurement
010: Y co-ordinate measurement
011: Pressure measurement
(4-wire touchpanels only)
100: COMP1/AUX1 measurement (pin 29)
101: COMP2/AUX2 measurement (pin 30)
110: BMON/AUX3 measurement (pin 31)
111: WIPER/AUX4 measurement (pin 12)
11:0
ADCD
000h
Touchpanel ADC Data (read-only)
Bit 11 = MSB
Bit 0 = LSB
78h
9
WAIT
0
0: No effect (new ADC data overwrites
unread data in register 7Ah)
1: New data is held back, and
measurements delayed, until register 7Ah is
read)
Table 29 Touchpanel Digitiser Data
To avoid losing data that has not yet been read, the WM9712L can delay overwriting register 7Ah with
new data until the old data has been read. This function is enabled using the WAIT bit.
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If the SLEN bit is set to ‘1’, then the touchpanel data appears on the AC-Link slot selected by the SLT
control bits, as shown below. The Slot 0 ‘tag’ bit corresponding to the selected time slot is asserted
whenever there is new data on that slot.
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
76h
3
SLEN
0
DESCRIPTION
Slot Readback Enable
0: Disabled (readback through register only)
1: Enable (readback slot selected by SLT)
2:0
SLT
110
AC’97 Slot Selection for Touchpanel Data
000: Slot 5
001: Slot 6
…
101: Slot 10
110: Slot 11
111: RESERVED
Table 30 Returning Touchpanel Data through an AC-Link Time Slot
TOUCHPANEL SETTLING TIME
For accurate touchpanel measurements, some settling time may be required between the switch
matrix applying a voltage across the touchpanel plate and the ADC sampling the signal. This time
delay function is built into the WM9712L and can be programmed as shown below.
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
76h
7:4
DEL
0000
Touchpanel ADC Settling Time
(1 frame)
Table 31 Touchpanel Settling Time Control (1)
DEL
DELAY
DELAY
(AC-LINK FRAMES)
(TIME)
0000
1
20.8s
0001
2
41.7s
0010
4
83.3s
0011
8
167s
0100
16
333s
0101
32
667s
0110
48
1ms
0111
64
1.33ms
1000
96
2ms
1001
128
2.67ms
1010
160
3.33ms
1011
192
4ms
1100
224
4.67ms
1101
256
5.33ms
1110
288
6ms
1111
No delay, switch matrix always on
Table 32 Touchpanel Settling Time Control (2)
The total time for co-ordinate or auxiliary measurements to complete is the delay time DEL, plus one
AC-Link frame (20.8s). For a pressure measurement, the time taken is DEL plus two AC-Link frames
(41.6s).
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Setting DEL to ‘1111’ reduces the settling time to zero, i.e. measurements begin immediately. This
mode is intended for fast sampling on AUX inputs. It is NOT intended for touchpanel digitisation.
There are several side-effects when DEL is set to ‘1111’:

Co-ordinate mode does not work, i.e. the WM9712L behaves as if COO = 0, even if COO
= 1 (see “Measurement Types”)
If X / Y co-ordinate or touch pressure measurements are selected (ADCSEL = 001, 010 or
011), then the switch matrix is constantly on, and current constantly flows in the
touchpanel. This increases power consumption in the system, and is therefore not
recommended for battery powered systems


In continuous mode (CTC = 1), setting DEL = 1111 increases the sampling rate of the
touchpanel ADC (see “Initiation of Measurements”)
MASK INPUT CONTROL
Sources of glitch noise, such as the signals driving an LCD display, may feed through to the
touchscreen plates and affect measurement accuracy. In order to minimise this effect, a signal may
be applied to MASK (pin 47) to delay or synchronise the sampling of any input to the ADC. The effect
of the MASK signal depends on the the MSK[1-0] bits of register 78h, as described below.
MSK[1-0]
EFFECT OF SIGNAL ON MASK PIN
00
Mask has no effect on conversions GPIO input disabled (default)
01
Static; ‘hi’ on MASK pin stops conversions, ‘lo’ has no effect.
10
Edge triggered; rising or falling edge on MASK pin delays conversions
by an amount set in the DEL[3-0] register. Conversions are asynchronous to
the MASK signal.
11
Synchronous mode; conversions wait until rising or falling edge on MASK
initiates cycle; screen starts to be driven when the edge arrives, the
conversion sample being taken a period set by DEL[3-0] after the edge.
Table 33 Controlling the MASK Feature
Note that pin 47 can also be used as a GPIO(see “GPIO and Interrupt Control” section), or to output
the ADA signal (see below).
THE ADA SIGNAL
Whenever data becomes available from the touchpanel ADC, the internal ADA (ADC Data Available)
signal goes high and remains high until the data has been read from register 7Ah (if SLEN = 0) or
until it has been sent out on an AC-Link slot (if SLEN = 1).
ADA can be used to generate an interrupt, if the AW bit (register 52h, bit 12) is set (see “GPIO and
interrupt control” section)
It is also possible to output the ADA signal on pin 47, if this pin is not used as a GPIO. The GE4 bit
(register 56h, bit 12) must be set to ‘0’ to achieve this (see “GPIO and interrupt control” section).
Alternatively, ADA can be read from bit 12 in register 54h.
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AUXILIARY ADC INPUTS
The ADC used for touchpanel digitisation can also be used for auxiliary measurements, provided that
it is enabled (register 78h, PRP = 11). The WM9712L has four pins that can be used as auxiliary ADC
inputs:

COMP1 / AUX1 (pin 29)


COMP2 / AUX2 (pin 30)
BMON / AUX3 (pin 31)

WIPER / AUX4 (pin 12)
Note that pin 12 connects to the wiper of a 5-wire touchpanel wiper function. Auxiliary measurements
taken on pin 12 are only meaningful when it is not connected to a touchpanel (i.e. a 4-wire
touchpanel, or no touchpanel at all, is used). Pins 29 and 30 are also used as comparator inputs (see
Battery Alarm and Battery Measurement), but auxiliary measurements can still be taken on these pins
at any time. For the use of pin 31 see the “Battery Alarm And Battery Measurement” section, note that
the measured value from the BMON/AUX3 pin will be 1/3 of the actual value due to the potential
divider on this pin. The ADCSEL control bits select between different ADC inputs, as shown below.
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
76h
14:12
ADCSEL
000
Touchpanel
Digitiser
Control
DESCRIPTION
Touchpanel ADC Input Selector
000: No measurement
001-011: Touchpanel measurement (please
refer to Touchpanel Digitiser section)
100: COMP1 / AUX1 measurement (pin 29)
101: COMP2 AUX2 measurement (pin 30)
110: BMON / AUX3 measurement (pin 31)
111: WIPER / AUX 4 measurement (pin 12)
Table 34 Auxiliary ADC Measurements
Auxiliary ADC measurements are initiated in the same way as touchpanel measurements, and the
data is returned in the same manner. Please refer to the “Controlling the Touchpanel Interface”
section.
BATTERY MEASUREMENT USING THE BMON/AUX3 PIN
BMON/AUX3 (pin 31) has the capability to take inputs up to 5 volts (Assuming AVDD=3.3V) by
dividing down the input signal. The internal potential divider has a total resistance of 30k. However,
it is only connected to the pin when an AUX3 measurement is requested, and remains connected for
the duration of one AC-Link frame (20.83s, assuming a 24.576MHz clock crystal is used). The
effective input impedance of BMON/AUX3 is therefore given by:
RBMON = 30k  48kHz / [BMON sampling rate]
For example, if BMON is sampled ten times per second, the effective input resistance is 30k 
48kHz / 10Hz = 144M.
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BATTERY ALARM AND ANALOGUE COMPARATORS
The battery alarm function differs from battery measurement in that it does not actually measure the
battery voltage. Battery alarm only indicates “OK”, “Low” or “Dead”. The advantage of the battery
alarm function is that it does not require a clock and can therefore be used in low-power sleep or
standby modes.
VOLTAGE
REGULATOR
IALARM
AVDD, DCVDD, ...
AUX1/
COMP1
R1
C
VBATT
WM9712L
+
-
R2
R3
DEAD
BAT
VREF
AUX2/
COMP2
+
GPIO /
INTERRUPT
LOGIC
LOW
BAT
GPIO2/
IRQ
GPIO
PINS
Figure 13 Battery Alarm Example Schematic
The typical schematic for a dual threshold battery alarm is shown above. This alarm has two
thresholds, “dead battery” (COMP1) and “low battery” (COMP2). R1, R2 and R3 set the threshold
voltages. Their values can be up to about 1M in order to keep the battery current [IALARM = VBATT /
(R1+R2+R3)] to a minimum (higher resistor values may affect the accuracy of the system as leakage
currents into the input pins become significant).

Dead battery alarm: COMP1 triggers when VBATT < VREF  (R1+R2+R3) / (R2+R3)
A dead battery alarm is the highest priority of interrupt in the system. It should immediately save all
unsaved data and shut down the system. The GP15, GS15 and GW15 bits must be set to generate
this interrupt.

Low battery alarm: COMP2 triggers when VBATT < VREF  (R1+R2+R3) / R3
A low battery alarm has a lower priority than a dead battery alarm. Since the threshold voltage is
higher than for a dead battery alarm, there is enough power left in the battery to give the user a
warning and/or shut down “gracefully”. When VBATT gets close to the low battery threshold, spurious
alarms are filtered out by the COMP2 delay function.
The purpose of the capacitor C is to remove from the comparator inputs any high frequency noise or
glitches that may be present on the battery (for example, noise generated by a charge pump). It forms
a low pass filter with R1, R2 and R3.

Low pass cutoff fc [Hz] = 1/ (2 C  (R1 || (R2+R3)))
Provided that the cutoff frequency is several orders of magnitude lower than the noise frequency fn,
this simple circuit can achieve excellent noise rejection.

Noise rejection [dB] = 20 log (fn / fc)
The circuit shown above also allows for measuring the battery voltage VBATT. This is achieved simply
by setting the touchpanel ADC input to be either COMP1 (ADCSEL = 100) or COMP2 (ADCSEL =
101) (see also Auxiliary ADC Inputs).
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The WM9712L has two on-chip comparators that can be used to implement a battery alarm function,
or other functions such as a window comparator. Each comparator has one of its inputs tied to any
one of three device pins and the other tied to a voltage reference. The voltage reference can be either
internally generated (VREF = AVDD/2) or externally connected on AUX4 (pin 12).
The comparator output signals are passed to the GPIO logic block (see “GPIO and Interrupt Control”
section), where they can be used to send an interrupt to the CPU via the AC-Link or via the IRQ pin,
and / or to wake up the WM9712L from sleep mode. COMP1/AUX1 (pin 29) corresponds to GPIO bit
15 and COMP2/AUX2 (pin30) to bit 14.
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
4Eh
15
CP1
1
COMP1 Polarity (see also “GPIO and Interrupt
Control”)
0: Alarm when COMP1 voltage is below VREF
1: Alarm when COMP1 voltage is above VREF
14
CP2
1
COMP2 Polarity (see also “GPIO and Interrupt
Control”)
0: Alarm when COMP2 voltage is below VREF
1: Alarm when COMP2 voltage is above VREF
58h
15:13
COMP2
DEL
0
Low Battery Alarm Delay
000: No delay
13
001: 0.17s (2 = 8192 AC-Link frames)
14
010: 0.34s (2 = 16384 AC-Link frames)
15
011: 0.68s (2 = 32768 AC-Link frames)
16
100: 1.4s (2 = 65536 AC-Link frames)
17
101: 2.7s (2 = 131072 AC-Link frames)
18
110: 5.5s (2 = 262144 AC-Link frames)
19
111: 10.9s (2 = 524288 AC-Link frames)
Table 35 Comparator Control
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
5Ch
14
C1REF
0
Comparator 1 Reference Voltage
Additional
Analogue
Functions
13:12
11
10:9
C1SRC
C2REF
C2SRC
00
0
00
0
VREF = AVDD/2
1
WIPER/AUX4 (pin 12)
Comparator 1 Signal Source
00
AVDD/2 when C1REF=’1’. Otherwise
comparator 1 is powered down
01
COMP1/AUX1 (pin 29)
10
COMP2/AUX2 (pin 30)
11
BMON/AUX3 (pin 31)
Comparator 2 Reference Voltage
0
VREF = AVDD/2
1
WIPER/AUX4 (pin 12)
Comparator 2 Signal Source
00
AVDD/2 when C2REF=’1’. Otherwise
comparator 2 is powered down
01
COMP1/AUX1 (pin 29)
10
COMP2/AUX2 (pin 30)
11
BMON/AUX3 (pin 31)
Table 36 Comparator Reference and Source Control
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COMP2 DELAY FUNCTION
COMP2 has an optional delay function for use when the input signal is noisy. When COMP2 triggers
and the delay is enabled (i.e. COMP2DEL is non-zero), then GPIO bit 14 does not change state
immediately, and no interrupt is generated. Instead, the WM9712L starts a delay timer and checks
COMP2 again after the delay time has passed. If COMP2 is still active, then the GPIO bit is set and
an interrupt may be generated (depending on the state of the GW14 bit). If COMP2 is no longer
active, the GPIO bit is not set, i.e. all register bits are as if COMP2 had never triggered.
Note: If COMP2 triggers while the WM9712L is in sleep mode, and the delay is enabled, then the
device starts the on-chip crystal oscillator in order to count the time delay.
COMP2
TRIGGERS
C2W?
0
END
Inactive
END
[FALSE ALARM]
1
COMP2
DEL?
non-zero
START TIMER
WAIT
time=COMP2DEL
000
SHUT DOWN
TIMER
COMP2?
Active
SET GI14
END
Figure 14 COMP2 Delay Flow Chart
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GPIO AND INTERRUPT CONTROL
The WM9712L has five GPIO pins that operate as defined in the AC’97 Revision 2.2 specification.
Each GPIO pin can be set up as an input or as an output, and has corresponding bits in register 54h
and in slot 12. The state of a GPIO output is determined by sending data through slot 12 of outgoing
frames (SDATAOUT). Data can be returned from a GPIO input by reading the register bit, or
examining slot 12 of incoming frames (SDATAIN). GPIO inputs can be made sticky, and can be
programmed to generate and interrupt, transmitted either through the AC-Link or through a dedicated,
level-mode interrupt pin (GPIO2/IRQ, pin 45).
GPIO pins 2 to 5 are multi-purpose pins that can also be used for other (non-GPIO) purposes, e.g. as
a SPDIF output or to signal pen-down. This is controlled by register 56h.
Independently of the GPIO pins, the WM9712L also has five virtual GPIOs. These are signals from
inside the WM9712L, which are treated as if they were GPIO input signals. From a software
perspective, virtual GPIOs are the same as GPIO pins, but they cannot be set up as outputs, and are
not tied to an actual pin. This allows for simple, uniform processing of different types of signals that
may generate interrupts (e.g. pen down, battery warnings, jack insertion, high-temperature warning,
or GPIO signals).
Figure 15 GPIO Logic
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GPIO
BIT
SLOT12
BIT
TYPE
PIN NO.
DESCRIPTION
1
5
GPIO Pin
44
GPIO1
2
6
GPIO Pin
45
GPIO2 / IRQ
3
7
GPIO Pin
46
4
8
GPIO Pin
47
5
9
GPIO Pin
48
enabled only when pin not used as IRQ
GPIO3 / PENDOWN
enabled only when pin not used as PENDOWN
GPIO4 / ADA / MASK
enabled only when pin not used as ADA
GPIO5 / SPDIF_OUT
enabled only when pin not used as
SPDIF_OUT
6-10
N/A
Unused
-
GPIO Logic not implemented for these bits
11
15
Virtual
GPIO
[Thermal Cutout]
Internal thermal cutout signal, indicates when
internal temperature reaches approximately
150C (see “Thermal Sensor”)
virtual
GPIO
-
Internal ADA (ADC Data Available) Signal
[ADA]
enabled only when auxiliary ADC is active
12
13
14
15
16
17
18
19
Virtual
GPIO
[PEN DOWN]
Virtual
GPIO
[COMP2]
Virtual
GPIO
-
[COMP1]
Internal PENDOWN Signal
enabled only when pen-down detection is
active
Internal COMP2 output (Low Battery Alarm)
enabled only when COMP2 is on
Internal COMP1 output (Dead Battery Alarm)
enabled only when COMP1 is on
Table 37 GPIO Bits and Pins
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The properties of the GPIOs are controlled through registers 4Ch to 52h, as shown below.
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
4Ch
n
GCn
1
DESCRIPTION
GPIO Pin Configuration
0: Output
1: Input
GC11-15 are always ‘1’
Unused bits GC6-GC10 are always ‘0’
4Eh
n
GPn
1
GPIO Pin Polarity / Type
0: Active Low
1: Active High
[GIn = pin level XNOR GPn]
Unused bits GP6-GP10 are always ‘1’
50h
n
GSn
0
GPIO Pin Sticky
1: Sticky
0: Not Sticky
Unused bits GS6-GS10 are always ‘0’
52h
n
GWn
0
GPIO Pin Wake-up
1: Wake Up (generate interrupts from this pin)
0: No wake-up (no interrupts generated)
Unused bits GW6-GW10 are always ‘0’
54h
n
GIn
N/A
GPIO Pin Status
Read: Returns status of each GPIO pin
Write: Writing ‘0’ clears sticky bit
Unused bits GI6-GI10 are always ‘0’
Table 38 GPIO Control
The following procedure is recommended for handling interrupts:
When the controller receives an interrupt, check register 54h. For each GPIO bit in descending order
of priority, check if the bit is ‘1’. If yes, execute corresponding interrupt routine, then write ‘0’ to
corresponding bit in 54h. If no, continue to next lower priority GPIO. After all GPIOs have been
checked, check if the interrupt still present or no. If yes, repeat procedure. If no, then jump back to
process that ran before the interrupt.
If the system CPU cannot execute such an interrupt routine, it may be preferable to switch internal
signals (such as PENDOWN) directly onto the GPIO pins. However, in this case the interrupt signals
cannot be made sticky, and more GPIO pins are tied up both on the WM9712L and on the CPU.
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REGISTER
ADDRESS
BIT
LABEL
DEFAULT
56h
2
GE2
1
DESCRIPTION
GPIO2 / IRQ output select
GPIO pins
function
select
0: Pin 45 disconnected from GPIO logic
set 4Ch, bit 2 to ‘0’ to output IRQ signal
1: Pin 45 connected to GPIO logic (IRQ disabled)
3
GE3
1
GPIO3 / PENDOWN output select
0: Pin 46 disconnected from GPIO logic
set 4Ch, bit 3 to ‘0’ to output PENDOWN signal
1: Pin 46 connected to GPIO logic
4
GE4
1
GPIO4 / ADA / MASK output select
0: Pin 47 disconnected from GPIO logic
set 4Ch, bit 4 to ‘0’ to output ADA signal
set 4Ch, bit 4 to ‘1’ to input MASK signal
1: Pin 47 connected to GPIO logic
5
GE5
1
GPIO5 / SPDIF output select
0: Pin 48 = SPDIF (disconnected from GPIO logic)
set 4Ch, bit 5 to ‘0’ to output SPDIF signal
1: Pin 48 connected to GPIO logic (SPDIF
disabled)
Table 39 Using GPIO Pins for Non-GPIO Functions
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
58h
0
IRQ INV
0
Additional
Functional
Control
DESCRIPTION
Inverts the IRQ signal (pin 45)
0: IRQ signal not inverted
1: IRQ signal inverted
1
WAKEEN
0
Enables GPIO wake-up
0: Disabled
1: Enabled
Table 40 Additional Functionality for GPIO Pins
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POWER MANAGEMENT
The WM9712L includes the standard power down control register defined by the AC’97 specification
(register 26h). Additionally, it also allows more specific control over the individual blocks of the device
through register 24h. Each particular circuit block is active when both the relevant bit in register 26h
AND the relevant bit in register 24h are set to ‘0’.
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
NORMAL
PIN 47 ‘HI’
DURING
RESET
26h
14
PR6
0 (ON)
1 (OFF)
Powerdown/
Status
register
Disables HPOUTL, HPOUTR and
OUT3 Buffer
13
PR5
0 (ON)
1 (OFF)
Disables internal clock
12
PR4
0 (ON)
1 (OFF)
Disables AC-link interface
(external clock off)
11
PR3
0 (ON)
1 (OFF)
Disables VREF, analogue mixers
and outputs
10
PR2
0 (ON)
1 (OFF)
Disables analogue mixers, LOUT2,
ROUT2 (but not VREF)
9
PR1
0 (ON)
1 (OFF)
Disables stereo DAC
8
PR0
0 (ON)
1 (OFF)
Disables audio ADCs and input
Mux
3
REF
1
0
Read-only bit, indicates VREF is
ready (inverse of PR2)
2
ANL
1
0
Read-only bit, indicates analogue
mixers are ready (inverse of PR3)
1
DAC
1
0
Read-only bit, indicates audio
DACs are ready (inverse of PR1)
0
ADC
1
0
Read-only bit, indicates audio
ADCs are ready (inverse of PR0)
Table 41 Powerdown and Status Register (Conforms to AC’97 Rev 2.2)
As can be seen from the table above, most blocks are ‘ON’ by default. However, if pin 47
(GPIO4/ADA/MASK) is held high during reset, the WM9712L starts up with all blocks powered down
by default, saving power. This is achieved by connecting a pull-up resistor (e.g. 100k) from pin 47 to
DBVDD. Note that the state of pin 47 during reset only affects register 26h.
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REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
24h
15
PD15
0 (ON)
Disables Crystal Oscillator
Additional
power down
control
14
PD14
0 (ON)
Disables left audio DAC
13
PD13
0 (ON)
Disables right audio DAC
12
PD12
0 (ON)
Disables left audio ADC
11
PD11
0 (ON)
Disables right audio ADC
10
PD10
0 (ON)
Disables MICBIAS
9
PD9
0 (ON)
Disables left headphone mixer
8
PD8
0 (ON)
Disables right headphone mixer
7
PD7
0 (ON)
Disables speaker mixer
6
PD6
0 (ON)
Disables MONO_OUT buffer (pin 33) and phone
mixer
5
PD5
0 (ON)
Disables OUT3 buffer (pin 37)
4
PD4
0 (ON)
Disables headphone buffers (HPOUTL/R)
3
PD3
0 (ON)
Disables speaker outputs (LOUT2, ROUT2)
2
PD2
0 (ON)
Disables Line Input PGA (left and right) *
1
PD1
0 (ON)
Disables Phone Input PGA *
0
PD0
0 (ON)
Disables Mic Input PGA (left and right) *
Note: When analogue inputs or outputs are disabled, they are internally connected to VREF
through a large resistor (VREF=AVDD/2 except in OFF mode, when VREF itself is disabled). This
maintains the potential at that node and helps to eliminate pops when the pins are re-enabled.
Table 42 Extended Power Down Register (Additional to AC’97 Rev 2.2)
Note:
*When disabling a PGA, always ensure that it is muted first.
ADDITIONAL POWER MANAGEMENT:

AUXDAC: see “Auxiliary DAC” section. AUXDAC is OFF by default.

Touchpanel Interface: see “Controlling the Touchpanel Digitiser / Power Management”.
The touchpanel digitiser is OFF by default.
SLEEP MODE
Whenever the PR4 bit (reg. 26h) is set, the AC-Link interface is disabled, and the WM9712L is in
sleep mode. There is in fact a very large number of different sleep modes, depending on the other
control bits. For example, the low-power standby mode described below is a sleep mode. It is
desirable to use sleep modes whenever possible, as this will save power. The following functions do
not require a clock and can therefore operate in sleep mode:


Analogue-to-analogue audio (DACs and ADCs unused), e.g. phone call mode
Pen-down detection


GPIO and interrupts
Battery alarm / analogue comparators (but not battery measurement)
The WM9712L can awake from sleep mode as a result of



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A warm reset on the AC-Link (according to the AC’97 specification)
A signal on a GPIO pin (if the pin is configured as an input, with wake-up enabled – see
“GPIO and Interrupt Control” section)
A virtual GPIO event such as pen-down, battery alarm, etc. (see “GPIO and Interrupt
Control” section)
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LOW POWER STANDBY MODE
If all the bits in registers 26h and 24h are set, then the WM9712L is in low-power standby mode and
consumes very little current. A 1M resistor string remains connected across AVDD to generate
VREF. This is necessary if the on-chip analogue comparators are used (see “Battery Alarm and
Battery Measurement” section), and helps shorten the delay between wake-up and playback
readiness. If VREF is not required, the 1M resistor string can be disabled by setting the SVD bit,
reducing current consumption further.
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
58h
10
SVD
0
DESCRIPTION
VREF Disable
0: VREF enabled using 1M string (low-power
standby mode)
1 : VREF disabled, 1M string disconnected
(OFF mode)
Table 43 Disabling VREF (for lowest possible power consumption)
SAVING POWER AT LOW SUPPLY VOLTAGES
The analogue supplies to the WM9712L can run from 1.8V to 3.6V. By default, all analogue circuitry
on the IC is optimized to run at 3.3V. This set-up is also good for all other supply voltages down to
1.8V. However, at lower voltages, it is possible to save power by reducing the internal bias currents
used in the analogue circuitry. This is controlled as shown below.
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
5Ch
6:5
VBIAS
00
DESCRIPTION
Analogue Bias optimization
11 : Lowest bias current, optimized for 1.8V
10 : Low bias current, optimized for 2.5V
01, 00 : Default bias current, optimized for 3.3V
Table 44 Analogue Bias Selection
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AC97 DATA AND CONTROL INTERFACE
INTERFACE PROTOCOL
The WM9712Lhas a single AC’97 interface for both data transfer and control. The AC-Link uses 5
wires:

SDATAIN (pin 8) carries data from the WM9712L to the controller


SDATAOUT (pin 5) carries data from the controller to the WM9712L
BITCLK (pin 6) is a clock, normally generated by the WM9712L crystal oscillator and
supplied to the controller. However, BITCLK can also be passed to the WM9712L from
an off-chip generator.
SYNC is a synchronization signal generated by the controller and passed to the
WM9712L
RESETB resets the WM9712L to its default state


AC-LINK
CONTROLLER
e.g. CPU
SYNC
BITCLK
SDATAIN
SDATAOUT
RESETB
24.576MHz
XTAL
WM9712L
ANALOGUE
INPUTS /
OUTPUTS
Figure 16 AC-Link Interface (typical case with BITCLK generated by the AC97 CODEC)
The SDATAIN and SDATAOUT signals each carry 13 time-division multiplexed data streams (slots 0
to 12). A complete sequence of slots 0 to 12 is referred to as an AC-Link frame, and contains a total
of 256 bits. The frame rate is 48kHz. This makes it possible to simultaneously transmit and receive
multiple data streams (e.g. audio, touchpanel, AUXDAC, control) at sample rates up to 48kHz.
Detailed information can be found in the AC’97 (Revision 2.2) specification, which can be obtained at
www.intel.com/labs/media/audio/
Note:
SDATAOUT and SYNC must be held low for when RESETB is applied. These signals must be held
low for the entire duration of the RESETB pulse and especially during the low-to-high transition of
RESETB. If either is set high during reset the AC'97 device may enter test modes. Information
relating to this operation is available in the AC'97 specification or in Wolfson applications note WAN0104 available at www.wolfsonmirco.com.
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INTERFACE TIMING
Test Characteristics:
DBVDD = 3.3V, DCVDD = 3.3V, DGND1 = DGND2 = 0V, TA = -25C to +85C, unless otherwise stated.
CLOCK SPECIFICATIONS
tCLK_HIGH
tCLK_LOW
BITCLK
tCLK_PERIOD
tSYNC_HIGH
tSYNC_LOW
SYNC
tSYNC_PERIOD
Figure 17 Clock Specifications (50pF External Load)
PARAMETER
SYMBOL
MIN
BITCLK frequency
TYP
MAX
12.288
BITCLK period
MHz
81.4
tCLK_PERIOD
BITCLK output jitter
ns
750
ps
ns
BITCLK high pulse width (Note 1)
tCLK_HIGH
36
40.7
45
BITCLK low pulse width (Note 1)
tCLK_LOW
36
40.7
45
SYNC frequency
UNIT
48
ns
kHz
tSYNC_PERIOD
20.8
s
SYNC high pulse width
tSYNC_HIGH
1.3
s
SYNC low pulse width
tSYNC_LOW
19.5
s
SYNC period
Note:
1. Worst case duty cycle restricted to 45/55
DATA SETUP AND HOLD
Figure 18 Data Setup and Hold (50pF External Load)
Note:
Setup and hold times for SDATAIN are with respect to the AC’97 controller, not the WM9712L.
PARAMETER
MIN
tSETUP
10
Hold from falling edge of BITCLK
tHOLD
10
Output valid delay from rising edge of
BITCLK
w
SYMBOL
Setup to falling edge of BITCLK
tCO
TYP
MAX
UNIT
ns
ns
15
ns
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SIGNAL RISE AND FALL TIMES
triseCLK
tfallCLK
BITCLK
triseSYNC
tfallSYNC
SYNC
triseDIN
tfallDIN
triseDOUT
tfallDOUT
SDATAIN
SDATAOUT
Figure 19 Signal Rise and Fall Times (50pF External Load)
PARAMETER
SYMBOL
MIN
TYP
MAX
UNIT
Incoming signals (from the AC’97 controller to the WM9712L)
SDATAOUT rise time
triseDOUT
6
SDATAOUT fall time
tfallDOUT
6
ns
SYNC rise time
triseSYNC
6
ns
SYNC fall time
tfallSYNC
6
ns
ns
Outgoing signals (from the WM9712L to the AC’97 controller)
BITCLK rise time
triseCLK
2
6
ns
BITCLK fall time
tfallCLK
2
6
ns
SDATAIN rise time
triseDIN
2
6
ns
SDATAIN fall time
tfallDIN
2
6
ns
AC-LINK POWERDOWN
SLOT 1
SLOT 2
SYNC
BITCLK
SDATAOUT
WRITE
TO 0X20
DATA PR4
DON'T
CARE
tS2_PDOWN
SDATAIN
Figure 20 AC-Link Powerdown Timing
AC-Link powerdown occurs when PR4 (register 26h, bit 12) is set (see “Power Management” section).
PARAMETER
End of Slot 2 to BITCLK and SDATAIN
low
w
SYMBOL
tS2_PDOWN
MIN
TYP
MAX
1.0
UNIT
s
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COLD RESET (ASYNCHRONOUS, RESETS REGISTER SETTINGS)
tRST_LOW
tRST2CLK
RESETB
BITCLK
Figure 21 Cold Reset Timing
Note:
For correct operation SDATAOUT and SYNC must be held LOW for entire RESETB active
low period otherwise the device may enter test mode. See AC'97 specification or Wolfson
applications note WAN104 for more details.
PARAMETER
SYMBOL
MIN
TYP
MAX
UNIT
RESETB active low pulse width
tRST_LOW
1.0
s
RESETB inactive to BITCLK startup
delay
tRST2CLK
162.8
ns
WARM RESET (ASYNCHRONOUS, PRESERVES REGISTER SETTINGS)
Figure 22 Warm Reset Timing
PARAMETER
SYNC active high pulse width
SYNC inactive to BITCLK startup
delay
w
SYMBOL
MIN
tRST2CLK
TYP
1.3
tSYNC_HIGH
162.4
MAX
UNIT
s
ns
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REGISTER MAP
Note: Highlighted bits differ from the AC’97 specification (newly added for non-AC’97 function, or same bit used in a
different way, or for another function)
Reg
Name
15
14
13
12
SE3
SE2
11
10
9
8
7
SE1
SE0
ID9
ID8
6
5
4
ID5
ID4
3
2
1
0
Default
ID3
ID2
ID1
ID0
6174h
00h
Reset
0
SE4
ID7
ID6
02h
LOUT2/ROUT2 Volume
MU
0
LOUT2 Volume
ZC
INV
ROUT2 Volume
8000h
04h
Headphone Volume
MU
0
HPOUTL Volume
ZC
0
HPOUTR Volume
8000h
06h
MONOOUT Volume
MU
0
0
0
08h
DAC Tone Control
BB
0
0
BC
PCBEEP Input
B2H
PHONE Volume
P2H
P2S
0
0Eh
MIC Volume
0
M12P
M22P
10h
LINEIN Volume
L2H
L2S
12h
AUXDAC Volume / Routing
A2H
14h
Sidetone Volume
STM
16h
OUT3 Volume
MU
0
0
18h
DAC Volume
D2H
D2S
D2P
1Ah
Record Select
Record Gain
20h
General Purpose
22h
DAC 3D Control
24h
Powerdown
26h
Powerdown Ctrl/Stat
0
0
0
BASS
B2HVOL
0Ah
0Ch
1Ch
0
B2SVOL
B2S
0
0
0
0
0
SRC
Left DAC Volume
0
BOOST
R2P
RMU
GRL
(Extended)
0
0
RECSL
R2P
BST
3DE
RECVOLL
0
0
0
0
0
0
0
ZC
0
0
0
0
0F0Fh
0
0
C008h
MICVOL (Mono /Right)
6808h
LINEINRVOL
0
0
E808h
0
0
0
AXE
AAA0h
0
0
0
0
AD00h
OUT3 Volume
8000h
Right DAC Volume
0
0
0
ZC
GRR
0
0
LB
0
0
0
AAA0h
PHONEIN Volume
0
A2PVOL
A2P
8000h
TRBL
0
0
MS
ALCVOL
OUT3SRC
0
MONOOUT Volume
TC
B2PVOL
0
0
ALCM
STVOL
0
20dB
A2SVOL
A2S
0
DAT
0
LINEINLVOL
L2P
0
0
B2P
0
LMICVOL (Left Only)
A2HVOL
ZC
E808h
RECSR
0
(Extended)
3000h
RECVOLR
0
0
8000h
0
0
0000h
0000h
3DDEPTH
0
0
0
0
0
0
0
0
0
0
3DLC
3DUC
PD15
PD14
PD13
PD12
PD11
PD10
PD9
PD8
PD7
PD6
PD5
PD4
PD3
PD2
PD1
PD0
0000h
0
PR6
PR5
PR4
PR3
PR2
PR1
PR0
0
0
0
0
REF
ANL
DAC
ADC
Default for reg. 26h - pin 47 "low"
000Fh
Default for reg. 26h - pin 47 "high" during reset (recommended for lowest power)
FF00h
28h
Extended Audio ID
ID1
ID0
0
0
REV1
REV0
AMAP
LDAC
SDAC
CDAC
2Ah
Ext’d Audio stst/ctrl
0
0
0
0
0
SPCV
0
0
0
0
0
0
SPSA
VRM
SPDIF
DRA
VRA
0405h
0
SEN
0
VRA
0410h
DACSR (Audio DACs Sample Rate)
BB80h
AUXDACSR (Auxiliary DAC Sample Rate)
BB80h
2Ch
Audio DACs Sample Rate
2Eh
AUXDAC Sample Rate
32h
Audio ADCs Sample Rate
3Ah
SPDIF control
V
DRS
4Ch
GPIO Pin Configuration
1
1
1
1
1
0
0
0
0
0
GC5
GC4
GC3
GC2
GC1
0
F83Eh
4Eh
GPIO Pin Polarity / Type
C1P
C2P
PP
AP
TP
1
1
1
1
1
GP5
GP4
GP3
GP2
GP1
1
FFFFh
50h
GPIO Pin Sticky
C1S
C2S
PS
AS
TS
0
0
0
0
0
GS5
GS4
GS3
GS2
GS1
0
0000h
52h
GPIO Pin Wake-Up
C1W
C2W
PW
AW
TW
0
0
0
0
0
GW5
GW4
GW3
GW2
GW1
0
0000h
54h
GPIO Pin Status
C1I
C2I
PI
AI
TI
0
0
0
0
0
GI5
GI4
GI3
GI2
GI1
0
GPIO pins
56h
GPIO Pin Sharing
1
1
GE3
GE2
1
0
F83Eh
58h
Additional Functions (1)
WAKE
EN
IRQ
INV
0008h
5Ah
Vendor Reserved
5Ch
Add. Functions (2)
5Eh
Vendor Reserved
60h
ALC Control
62h
ALC / Noise Gate Control
64h
AUXDAC input control
66h- Vendor Reserved
74h
76h Digitiser Reg 1
78h
Digitiser Reg 2
7Ah
Digitiser Read Back
ADCSR (Audio ADCs Sample Rate)
1
SPSR
COMP2DEL
BB80h
CC (Category Code)
L
PRE
1
1
0
0
0
0
0
GE5
GE4
JIEN
FRC
SVD
0
0
0
0
0
0
COPY AUD IB PRO
Die Revision
2000h
RESERVED FOR TEST
AMUTE
C1 REF
C1SRC
C2 REF
C2SRC
DS
VBIAS
AMEN
ADCO
HPF
ASS
ENT
0000h
RESERVED FOR TEST
ALCL (target level)
MAXGAIN
ALCSEL
XSLE
HLD (hold time)
ZC TIMEOUT
DCY (decay time)
ALC
ZC
AUXDACSLT
NG AT
0
NGG
ATK (attack time)
NGTH (threshold)
AUXDAC VAL
B032h
3E00h
0000h
RESERVED. DO NOT WRITE TO THESE REGISTERS
POLL
PRP
PNDN
ADCSEL
RPR
45W
COO
CTC
PDEN
0
ADCSRC
DEL
CR
WAIT
PIL
SLT
SLEN
MSK
RPU
ADCD (TOUCHPANEL ADC DATA)
0006h
0001h
0000h
7Ch
Vendor ID1
ASCII character “W”
ASCII character “M”
574Dh
7Eh
Vendor ID2
ASCII character “L”
“12” (indicates part number WM9712)
4C12h
Table 45 WM9712L Register Map
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REGISTER BITS BY ADDRESS
Register 00h is a read-only register. Writing any value to this register resets all registers to their default, but does not
change the contents of reg. 00h. Reading the register reveals information about the CODEC to the driver, as required by the
AC’97 Specification, Revision 2.2
REG
ADDR
BIT
LABEL
00h
14:10
SE [4:0]
9:6
ID9:6
DEFAULT
DESCRIPTION
REFER TO
11000
Indicates a CODEC from Wolfson Microelectronics
0101
Indicates 18 bits resolution for ADCs and DACs
Intel’s AC’97
Component
Specification,
Revision 2.2,
page 50
5
ID5
1
Indicates that the WM9712L supports bass boost
4
ID4
1
Indicates that the WM9712L has a headphone output
3
ID3
0
Indicates that the WM9712L does not support simulated stereo
2
ID2
1
Indicates that the WM9712L supports bass and treble control
1
ID1
0
Indicates that the WM9712L does not support modem functions
0
ID0
0
Indicates that the WM9712L does not have a dedicated microphone
ADC
Register 02h controls the output pins LOUT2 and ROUT2.
REG
ADDR
BIT
LABEL
DEFAULT
DESCRIPTION
REFER TO
02h
15
MU
1 (mute)
Mutes LOUT2 and ROUT2.
13:8
LOUT2 VOL
000000 (0dB)
LOUT2 volume
Analogue
Audio Outputs
7
ZC
0 (OFF)
Enables zero-cross detector
6
INV
0 (not inverted)
Inverts LOUT2 (for BTL speaker operation)
5:0
ROUT2 VOL
000000 (0dB)
ROUT2 volume
Register 04h controls the headphone output pins, HPOUTL and HPOUTR.
REG
ADDR
BIT
LABEL
DEFAULT
DESCRIPTION
REFER TO
04h
15
MU
1 (mute)
Mutes HPOUTL and HPOUTR.
13:8
HPOUTL VOL
000000 (0dB)
HPOUTL volume
Analogue
Audio Outputs
7
ZC
0 (OFF)
Enables zero-cross detector
5:0
HPOUTR VOL
000000 (0dB)
HPOUTR volume
Register 06h controls the analogue output pin MONOOUT.
REG
ADDR
06h
BIT
LABEL
DEFAULT
DESCRIPTION
REFER TO
Analogue
Audio Outputs
15
MU
1 (mute)
Mutes MONOOUT.
7
ZC
0 (OFF)
Enables zero-cross detector
5:0
MONOOUT
VOL
000000 (0dB)
MONOOUT volume
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Register 08h controls the bass and treble response of the left and right audio DAC (but not AUXDAC).
REG
ADDR
08h
BIT
LABEL
DEFAULT
DESCRIPTION
REFER TO
Audio DACs,
Tone Control /
Bass Boost
15
BB
0 (linear)
Selects linear bass control or adaptive bass boost
12
BC
0 (low)
Selects bass cut-off frequency
11:8
BASS
1111 (OFF)
Controls bass intensity
6
DAT
0 (OFF)
Enables 6dB pre-DAC attenuation
4
TC
0 (high)
Selects treble cut-off frequency
3:0
TRBL
1111 (OFF)
Controls treble intensity
Register 0Ah controls the analogue input pin PCBEEP.
REG
ADDR
0Ah
BIT
LABEL
DEFAULT
DESCRIPTION
REFER TO
Analogue
Inputs,
PCBEEP Input
15
B2H
1 (mute)
Mutes PCBEEP to headphone mixer path
14:12
B2HVOL
010 (0dB)
Controls gain of PCBEEP to headphone mixer path
11
B2S
1 (mute)
Mutes PCBEEP to speaker mixer path
10:8
B2SVOL
010 (0dB)
Controls gain of PCBEEP to speaker mixer path
7
B2P
1 (mute)
Mutes PCBEEP to phone mixer path
6:4
B2PVOL
010 (0dB)
Controls gain of PCBEEP to phone mixer path
Register 0Ch controls the analogue input pin PHONE.
REG
ADDR
0Ch
BIT
LABEL
DEFAULT
DESCRIPTION
REFER TO
Analogue
Inputs,
PHONE Input
15
P2H
1 (mute)
Mutes PHONE to headphone mixer path
14
P2S
1 (mute)
Mutes PHONE to speaker mixer path
4:0
PHONEVOL
01000 (0dB)
Controls PHONE input gain to all mixers (but not to ADC)
Register 0Eh controls the analogue input pins MIC1 and MIC2.
REG
ADDR
0Eh
BIT
LABEL
DEFAULT
DESCRIPTION
REFER TO
Analogue
Inputs,
Microphone
Input
14
M12P
1 (mute)
Mutes MIC1 to phone mixer path
13
M22P
1 (mute)
Mutes MIC2 to phone mixer path
12:8
LMICVOL
01000 (0dB)
Controls volume of MIC1 (left), in stereo mode only
7
20dB
0 (OFF)
Enables 20dB gain boost
6:5
MS
00 (MIC1 only)
Selects microphone mode. 00=MIC1 only, 01=differential,
10=MIC2 only, 11=stereo
4:0
MICVOL
01000 (0dB)
Controls mic volume (except MIC1 in stereo mode)
Register 10h controls the analogue input pins LINEINL and LINEINR.
REG
ADDR
BIT
LABEL
DEFAULT
DESCRIPTION
REFER TO
10h
15
L2H
1 (mute)
Mutes LINEIN to headphone mixer path
14
L2S
1 (mute)
Mutes LINEIN to speaker mixer path
13
L2P
1 (mute)
Mutes LINEIN to phone mixer path
Analogue
Inputs, Line
Input
12:8
LINEINLVOL
01000 (0dB)
Controls LINEINL input gain to all mixers (but not to ADC)
4:0
LINEINRVOL
01000 (0dB)
Controls LINEINR input gain to all mixers (but not to ADC)
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Register 12h controls the output signal of the auxiliary DAC.
REG
ADDR
12h
BIT
LABEL
DEFAULT
DESCRIPTION
REFER TO
15
A2H
1 (mute)
Mutes AUXDAC to headphone mixer path
Auxiliary DAC
14:12
A2HVOL
010 (0dB)
Controls gain of AUXDAC to headphone mixer path
Mutes AUXDAC to speaker mixer path
11
A2S
1 (mute)
10:8
A2SVOL
010 (0dB)
Controls gain of AUXDAC to speaker mixer path
7
A2P
1 (mute)
Mutes AUXDAC to phone mixer path
6:4
A2PVOL
010 (0dB)
Controls gain of AUXDAC to phone mixer path
0
AXE
0 (0FF)
Enables AUXDAC
Register 14h controls the side tone paths.
REG
ADDR
14h
BIT
LABEL
DEFAULT
DESCRIPTION
REFER TO
Audio Mixers,
Side Tone
Control
15
STM
1 (mute)
Mutes microphone to headphone mixer path
14:12
STVOL
010 (0dB)
Controls gain of microphone to headphone mixer path
11:10
ALCM
11 (mute both)
Selects ALC to headphone mixer path. 00=stereo, 01=right
only, 10=left only, 11=mute both left and right
9:7
ALCVOL
010 (0dB)
Controls gain of ALC to headphone mixer path
Register 16h controls the analogue output pin OUT3, and also contains one control bit that affects LOUT2 and ROUT2.
REG
ADDR
16h
BIT
LABEL
DEFAULT
DESCRIPTION
REFER TO
Analogue
Audio Outputs
15
MU
1 (mute)
Mutes OUT3.
10:9
OUT3SRC
00 (-HPOUTL)
Selects source of OUT3 signal. 00=-HPOUTL, 01=VREF,
10=HPOUTL+HPOUTR, 11=-MONOOUT
8
SRC
0 (spkr mix)
Selects source of LOUT2 and ROUT2 signals. 0=from
speaker mixer, 1=from headphone mixer
7
ZC
0 (disabled)
Zero-cross enable
5:0
OUT3VOL
000000 (0dB)
OUT3 volume
Register 18h controls the audio DACs (but not AUXDAC).
REG
ADDR
BIT
LABEL
DEFAULT
DESCRIPTION
REFER TO
18h
15
D2H
1 (mute)
Mutes DAC to headphone mixer path
Audio DACs
14
D2S
1 (mute)
Mutes DAC to speaker mixer path
13
D2P
1 (mute)
Mutes DAC to phone mixer path
12:8
LDACVOL
01000 (0dB)
Controls left DAC input gain to all mixers
4:0
RDACVOL
01000 (0dB)
Controls right DAC input gain to all mixers
Register 1Ah controls the record selector and the ADC to phone mixer path.
REG
ADDR
1Ah
BIT
LABEL
DEFAULT
DESCRIPTION
REFER TO
Audio ADC,
Record
Selector
14
BOOST
0 (OFF)
Enables 20dB gain boost for recording
13:12
R2P
11 (mute)
Controls ADC to phone mixer path. 00=stereo, 01=left
ADC only, 10=right ADC only, 11=mute left and right
11
R2PBST
0 (OFF)
Enables 20dB gain boost for ADC to phone mixer path
10:8
RECSL
000 (mic)
Selects left ADC signal source
2:0
RECSR
000 (mic)
Selects right ADC signal source
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Register 1Ch controls the.recording gain.
REG
ADDR
1Ch
BIT
LABEL
DEFAULT
DESCRIPTION
REFER TO
Audio ADC,
Record Gain
15
RMU
1 (mute)
Mutes audio ADC input
14
GRL
0 (standard)
Selects gain range for PGA of left ADC. 0=0...+22.5dB in
1.5dB steps, 1=-17.25...+30dB in 0.75dB steps
13:8
RECVOLL
000000 (0dB)
Controls left ADC recording volume
7
ZC
0 (OFF)
Enables zero-cross detector
6
GRR
0 (standard)
Selects gain range for PGA of left ADC. 0=0...+22.5dB in
1.5dB steps, 1=-17.25...+30dB in 0.75dB steps
5:0
RECVOLR
000000 (0dB)
Controls right ADC recording volume
Register 20h is a “general purpose” register as defined by the AC’97 specification. Only two bits are implemented in the
WM9712L.
REG
ADDR
BIT
LABEL
DEFAULT
DESCRIPTION
REFER TO
20h
13
3DE
0 (OFF)
Enables 3D enhancement
Audio DACs, 3D Stereo
Enhancement
7
LB
0 (OFF)
Enables loopback (i.e. feed ADC output data
directly into DAC)
Intel’s AC’97 Component
Specification, Revision 2.2, page 55
Register 22h controls 3D stereo enhancement for the audio DACs.
REG
ADDR
BIT
LABEL
DEFAULT
DESCRIPTION
REFER TO
22h
5
3DLC
0 (low)
Selects lower cut-off frequency
4
3DUC
0 (high)
Selects upper cut-off frequency
3:0
3DDEPTH
0000 (0%)
Controls depth of 3D effect
Audio DACs,
3D Stereo
Enhancement
Register 24h is for power management additional to the AC’97 specification. Note that the actual state of each circuit block
depends on both register 24h AND register 26h.
REG
ADDR
24h
BIT
LABEL
DEFAULT
DESCRIPTION
REFER TO
Power
Management
15
PD15
0*
Disables Crystal Oscillator
14
PD14
0*
Disables left audio DAC
13
PD13
0*
Disables right audio DAC
12
PD12
0*
Disables left audio ADC
11
PD11
0*
Disables right audio ADC
10
PD10
0*
Disables MICBIAS
9
PD9
0*
Disables left headphone mixer
8
PD8
0*
Disables right headphone mixer
7
PD7
0*
Disables speaker mixer
6
PD6
0*
Disables MONO_OUT buffer (pin 33) and phone mixer
5
PD5
0*
Disables OUT3 buffer (pin 37)
4
PD4
0*
Disables headphone buffers (HPOUTL/R)
3
PD3
0*
Disables speaker outputs (LOUT2, ROUT2)
2
PD2
0*
Disables Line Input PGA (left and right)
1
PD1
0*
Disables Phone Input PGA
0
PD0
0*
Disables Mic Input PGA (left and right)
* “0” corresponds to “ON”, if and only if the corresponding bit in register 26h is also 0.
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Register 26h is for power management according to the AC’97 specification. Note that the actual state of many circuit
blocks depends on both register 24h AND register 26h.
REG
ADDR
BIT
LABEL
DEFAULT
DESCRIPTION
REFER TO
14
PR6
see note
Disables HPOUTL, HPOUTR and OUT3 Buffer
13
PR5
Power
Management
Disables Internal Clock
12
PR4
Disables AC-link interface (external clock off)
11
PR3
Disables VREF, analogue mixers and outputs
10
PR2
Disables analogue mixers, LOUT2, ROUT2 (but not VREF)
9
PR1
Disables Stereo DAC and AUXDAC
8
PR0
Disables audio ADCs and input Mux
3
REF
inverse of PR2
Read-only bit, Indicates VREF is ready
2
ANL
inverse of PR3
Read-only bit, indicates analogue mixers are ready
1
DAC
inverse of PR1
Read-only bit, indicates audio DACs are ready
0
ADC
inverse of PR0
Read-only bit, indicates audio ADCs are ready
Note: PR6 to PR0 default to 1 if pin 47 is held high during reset, otherwise they default to 0.
Register 28h is a read-only register that indicates to the driver which advanced AC’97 features the WM9712L supports.
REG
ADDR
BIT
LABEL
DEFAULT
DESCRIPTION
REFER TO
28h
15:14
ID
00
Indicates that the WM9712L is configured as the primary CODEC in
the system.
11:10
REV
01
Indicates that the WM9712L conforms to AC’97 Rev2.2
9
AMAP
0
Indicates that the WM9712L does not support slot mapping
8
LDAC
0
Indicates that the WM9712L does not have an LFE DAC
Intel’s AC’97
Component
Specification,
Revision 2.2,
page 59
7
SDAC
0
Indicates that the WM9712L does not have Surround DACs
6
CDAC
0
Indicates that the WM9712L does not have a Centre DAC
3
VRM
0
Indicates that the WM9712L does not have a dedicated, variable rate
microphone ADC
2
SPDIF
1
Indicates that the WM9712L supports SPDIF output
1
DRA
0
Indicates that the WM9712L does not support double rate audio
0
VRA
1
Indicates that the WM9712L supports variable rate audio
Register 2Ah controls the SPDIF output and variable rate audio.
REG
ADDR
2Ah
BIT
LABEL
DEFAULT
DESCRIPTION
REFER TO
Digital Audio
(SPDIF)
Output
10
SPCV
1 (valid)
SPDIF validity bit (read-only)
5:4
SPSA
01 (slots 6, 9)
Controls SPDIF slot assignment. 00=slots 3 and 4, 01=6/9,
10=7/8, 11=10/11
2
SEN
0 (OFF)
Enables SPDIF output enable
0
VRA
0 (OFF)
Enables variable rate audio
Registers 2Ch, 2Eh 32h and control the sample rates for the stereo DAC, auxiliary DAC and audio ADC, respectively.
REG
ADDR
BIT
LABEL
DEFAULT
DESCRIPTION
REFER TO
Variable Rate
Audio /
Sample Rate
Conversion
2Ch
all
DACSR
BB80h
Controls stereo DAC sample rate
2Eh
all
AUXDACSR
BB80h
Controls auxiliary DAC sample rate
32h
all
ADCSR
BB80h
Controls audio ADC sample rate
Note: The VRA bit in register 2Ah must be set first to obtain sample rates other than 48kHz
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Register 3Ah controls the SPDIF output.
REG
ADDR
BIT
LABEL
DEFAULT
DESCRIPTION
REFER TO
3Ah
15
V
0
Validity bit; ‘0’ indicates frame valid, ‘1’ indicates frame not
valid
14
DRS
0
Indicates that the WM9712L does not support double rate
SPDIF output (read-only)
Digital Audio
(SPDIF)
Output
13:12
SPSR
10
Indicates that the WM9712L only supports 48kHz sampling
on the SPDIF output (read-only)
11
L
0
Generation level; programmed as required by user
10:4
CC
0000000
Category code; programmed as required by user
3
PRE
0
Pre-emphasis; ‘0’ indicates no pre-emphasis, ‘1’ indicates
50/15us pre-emphasis
2
COPY
0
Copyright; ‘0’ indicates copyright is not asserted, ‘1’
indicates copyright
1
AUDIB
0
Non-audio; ‘0’ indicates data is PCM, ‘1’ indicates nonPCM format (e.g. DD or DTS)
0
PRO
0
Professional; ‘0’ indicates consumer, ‘1’ indicates
professional
Register 4Ch to 54h control the GPIO pins and virtual GPIO signals.
REG
ADDR
BIT
LABEL
DEFAULT
DESCRIPTION
REFER TO
4Ch
all 1 (all inputs)
except unused
bits
Controls GPIO configuration as inputs or as outputs (note:
virtual GPIOs can only be inputs)
GPIO and
Interrupt
Control
4Eh
all 1
Controls GPIO polarity (actual polarity depends on register
4Ch AND register 4Eh)
50h
all 0 (not sticky)
Makes GPIO signals sticky
52h
all 0 (OFF)
Enables wake-up for each GPIO signal
54h
= status of GPIO
inputs
GPIO pin status (read from inputs, write ‘0’ to clear sticky bits)
15
14
13
12
please
refer to
the
register
map
Controls Comparator 1 signal (virtual GPIO)
Controls Comparator 2 signal (virtual GPIO)
Controls Pen-Down Detector signal (virtual GPIO)
Controls ADA signal (virtual GPIO)
11
Controls Thermal sensor signal (virtual GPIO)
10-6
Unused
5
Controls GPIO5 (pin 48)
4
Controls GPIO4 (pin 47)
3
Controls GPIO3 (pin 46)
2
Controls GPIO2 (pin 45)
1
Controls GPIO1 (pin 44)
Register 56h controls the use of GPIO pins for non-GPIO functions.
REG
ADDR
BIT
LABEL
DEFAULT
DESCRIPTION
REFER TO
56h
5
GE5
1 (GPIO)
Selects between GPIO5 and SPDIF_OUT function for pin 48
4
GE4
1 (GPIO)
Selects between GPIO4 and ADA/MASK functionS for pin 47
3
GE3
1 (GPIO)
Selects between GPIO3 and PENDOWN function for pin 46
GPIO and
Interrupt
Control
2
GE2
1 (GPIO)
Selects between GPIO2 and IRQ function for pin 45
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Register 58h controls several additional functions.
REG
ADDR
BIT
LABEL
DEFAULT
DESCRIPTION
58h
REFER TO
15:13
COMP2DEL
000 (no delay)
Selects Comparator 2 delay
Battery Alarm
12
JIEN
0
Enables Jack Insert Detection
11
FRC
0
Forces Jack Insert Detection
Analogue Audio Outputs, Jack
Insertion and Auto-Switching
10
SVD
0 (enabled)
Disables VREF for lowest possible power
consumption
3:2
DIE REV
Indicates device revision. 00=Rev.A, 01=Rev.B, 10=Rev.C
N/A
1
WAKEEN
0 (no wake-up)
Enables GPIO wake-up
GPIO and Interrupt Control
0
IRQ INV
0 (not inverted)
Inverts the IRQ signal (pin 45)
Power Management
Register 5Ch controls several additional functions.
REG
ADDR
5Ch
BIT
LABEL
DEFAULT
DESCRIPTION
REFER TO
15
AMUTE
0
Read-only bit to indicate DAC auto-muting
Audio DACs, Stereo DACs
14
C1REF
0 (AVDD/2)
Selects Comparator 1 Reference Voltage
Battery Alarm
13:12
C1SRC
00 (OFF)
Selects Comparator 1 Signal Source
11
C2REF
0 (AVDD/2)
Selects Comparator 1 Reference Voltage
10:9
C2SRC
00 (OFF)
Selects Comparator 1 Signal Source
8
DS
0
Selects differential microphone input pins. 0=MIC1
and MIC2, 1=LINEL and LINER
7
AMEN
0 (OFF)
Enables DAC Auto-Mute
6:5
VBIAS
00
Selects analogue bias for lowest power, depending
on AVDD supply. 0X=3.3V, 10=2.5V, 11=1.8V
Power Management
4
ADCO
0
Selects source of SPDIF data. 0=from SDATAOUT,
1= from audio ADC
Digital Audio (SPDIF) Output
3
HPF
0
Disables ADC high-pass filter
Audio ADC
2
ENT
0
Enables thermal sensor
Analogue Audio Outputs,
Thermal Sensor
1:0
ASS
00
Selects time slots for stereo ADC data. 00=slots 3
and 4, 01=7/8, 10=6/9, 11=10/11
Audio ADC, ADC Slot
Mapping
Analogue Inputs,
Microphone Input
Registers 60h and 62h control the ALC and Noise Gate functions.
REG
ADDR
BIT
LABEL
60h
15:12
ALCL
11:8
HLD
7:4
DCY
0011 (192 ms)
Controls ALC decay time
3:0
ATK
0010 (24 ms)
Controls ALC attack time
15:14
ALCSEL
00 (OFF)
Controls which channel ALC operates on. 00=none,
01=right only, 10=left only, 11=both
13:11
MAXGAIN
111 (+30dB)
Controls upper gain limit for ALC
10:9
ZC TIMEOUT
11 (slowest)
Controls time-out for zero-cross detection
8
ALCZC
0 (OFF)
Enables zero-cross detection for ALC
7
NGAT
0 (OFF)
Enables noise gate function
5
NGG
0 (hold gain)
Selects noise gate type. 0=hold gain, 1=mute
4:0
NGTH
00000 (-76.5dB)
Controls noise gate threshold
62h
w
DEFAULT
DESCRIPTION
REFER TO
1011 (-12dB)
Controls ALC threshold
0000 (0 ms)
Controls ALC hold time
Audio ADC,
Automatic
Level Control
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Register 64h controls the input signal of the auxiliary DAC.
REG
ADDR
BIT
LABEL
DEFAULT
DESCRIPTION
REFER TO
64h
15
XSLE
0
Selects input for AUXDAC. 0=from AUXDACVAL (for DC
signals), 1=from AC-Link slot (for AC signals)
Auxiliary DAC
14:12
AUXDACSLT
000 (Slot 5)
Selects input slot for AUXDAC (with XSLE=1)
11:0
AUXDACVAL
000000000
AUXDAC Digital Input for AUXDAC (with XSLE=0). 000h=
minimum, FFFh=full-scale
Registers 76h, 78h and 7Ah control the touchpanel interface.
REG
ADDR
76h
BIT
LABEL
DEFAULT
DESCRIPTION
REFER TO
Touchpanel
Interface
15
POLL
0
Writing “1” starts a measurement (this bit resets itself)
14:12
ADCSEL
000 (none)
Selects measurement type
11
COO
0 (OFF)
Enables co-ordinate mode
10
CTC
0 (polling)
Enables continuous conversions
9:8
CR
00 (93.75Hz)
Controls conversion rate in continuous mode
7:4
DEL
0000 (20.8s)
Controls touchpanel settling time
3
SLEN
1
Enables slot readback of touchpanel data
2:0
SLT
10
Selects time slot for readback of touchpanel data
15:14
PRP
00
Selects mode of operation. 00=OFF, 01=pen detect with wakeup, 10=pen detect without wake-up, 11=running
13
RPR
0
Selects wake-up mode. 0=AC-Link only, 1=AC-Link and
WM9712L auto-wake-up
12
45W
0 (4-wire)
Selects 4-wire or 5-wire touchpanel
11
PDEN
0 (always)
Selects when touchpanel measurements take place. 0=always,
1=only when pen is down
9
WAIT
0
Controls data readback from register 7Ah. 0=overwrite old data
with new, 1=wait until old data has been read
8
PIL
0 (200A)
Controls current used for pressure measurement. 1=400A
7:6
MSK
00 (OFF)
Controls MASK feature
5:0
RPU
000001 (64k)
Controls internal pull-up resistor for pen-down detection
7Ah
15
PNDN
0 (pen up)
Indicates pen status.
read
only
14:12
ADCSRC
000 (none)
Indicates measurement type
11:0
ADCD
000h
Returns data from touchpanel / AUXADC
78h
Register 7Ch and 7Eh are read-only registers that indicate to the driver that the CODEC is a WM9712L.
REG
ADDR
7Ch
7Eh
BIT
LABEL
DEFAULT
DESCRIPTION
REFER TO
Intel’s AC’97
Component
Specification,
Revision 2.2,
page 50
15:8
F7:0
57h
ASCII character “W” for Wolfson
7:0
S7:0
4Dh
ASCII character “M”
15:8
T7:0
4Ch
ASCII character “L”
7:0
REV7:0
12h
12 for WM9712L
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APPLICATIONS INFORMATION
RECOMMENDED EXTERNAL COMPONENTS
DVDD
AVDD
1
9
13
25
38
43
DGND1
DGND2
DBVDD
DCVDD
AGND1
AGND
SPKGND
HPGND
AGND2
AVDD2
AVDD
SPKVDD
HPVDD
C1 C2 C3 C4 C5 C6
GND
GND_PADDLE
AGND
MONOOUT
5
6
8
AC-LINK
10
11
14
15
16
17
AVDD
+ C7
AGND
DVDD
+ C8
GND
C15
19
C16
20
C17
21
C18
22
C19
23
C20
24
29
30
31
12
Layout Notes:
1. C1 to C6, C9 C11 and C13 should be as close to
the relative WM9712L connecting pin as possible.
2. AGND and DGND should be connected as close
to the WM9712L as possible.
3. For added strength and heat dissipation, it is recommended
that the GND_PADDLE(Pin 49) is connected to AGND.
SDATAOUT
LOUT2
BITCLK
ROUT2
OUT3
SDATAIN
SYNC
HPOUTL
RESETB
HPOUTR
4
7
18
26
34
40
42
GND
AGND
49
AGND
33
+ C21
35
+ C22
36
+ C23
37
+ C24
39
+ C25
41
+ C26
DBVDD
X+/BR
Y+/TR
X-/TL
Y-/BL
GPIO1
GPIO2/IRQ
GPIO3
GPIO4
GPIO/SPDIF_OUT
44
45
46
47
48
R1
R2
PCBEEP
One of the three possible
configurations MUST be used:
R1 - Default power down.
R2 - Default power on & GPIO
function used.
GND - Default power on &
GPIO function not used.
GND GND
PHONE
MIC1
WM9712L
MIC2
LINEINL
LINEINR
MICBIAS
COMP1
COMP2
COMP3
CREF
VREF
CAP2
XTLIN
28
27
C11
32
C9
C13
+ C14
+ C10
AGND
XTLOUT
2
+ C12
AGND
3
See External Components
Descriptions for details
XT
C28
C27
GND
Figure 23 External Components Diagram
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RECOMMENDED COMPONENTS VALUES
COMPONENT
REFERENCE
SUGGESTED
VALUE
DESCRIPTION
C1 - C6
100nF
De-coupling for DBVDD,DCVDD,TPVDD,AVDD,SPKVDD,HPVDD
C7 - C8
10uF
Reservoir capacitor for DVDD, AVDD. Should the supplies use separate sources then
additional capacitors will be required of each additional source.
C9
100nF
De-coupling for CAP2.
C10
10uF
Reservoir capacitor for CAP2
C11
100nF
De-coupling for VREF
C12
10uF
Reservoir capacitor for VREF
C13
100nF
De-coupling for MICBIAS - Not required if MICBIAS output is not used
C14
10uF
Reservoir capacitor for MICBIAS - Not required if MICBIAS output is not used
C27 & C28
22pF
Required when used with a parallel resonant crystal.
C15 - C20
1uF
AC coupling capacitors
Output AC coupling capacitors to remove VREF DC level from outputs
C21 - C23
2.2uF
C24 - C26
220F
Output AC coupling capacitors to remove VREF DC level from outputs.
R1
100k
Pull-up resistor, ensures that all circuit blocks are OFF by default
R2
100k
XT
24.576MHz
Pull down resistor, ensures that all circuit blocks are ON by default
AC'97 master clock frequency. A bias resistor is not required but if connected will not
affect operation if the value is large (above 1M)
Table 46 External Components Descriptions
Note:
1. For Capacitors C7, C8, C10, C12 and C14 it is recommended that very low ESR components are used.
LINE OUTPUT
The headphone outputs, HPOUTL and HPOUTR, can be used as stereo line outputs. The speaker
outputs, LOUT2 and ROUT2, can also be used as line outputs, if LOUT2 is not inverted for BTL
operation (INV = 0). Recommended external components are shown below.
C1
1uF
R1
100 Ohm
LINE-OUT
SOCKET
(LEFT)
HPOUTL /
LOUT2
HPGND
WM9712L
LINE-OUT
SOCKET
(RIGHT)
HPOUTR /
ROUT2
C2
1uF
R2
100 Ohm
HPGND
Figure 24 Recommended Circuit for Line Output
The DC blocking capacitors and the load resistance together determine the lower cut-off frequency,
fc. Assuming a 10 k load and C1, C2 = 10F:
fc = 1 / 2 (RL+R1) C1 = 1 / (2 x 10.1k x 1F) = 16 Hz
Increasing the capacitance lowers fc, improving the bass response. Smaller values of C1 and C2 will
diminish the bass response. The function of R1 and R2 is to protect the line outputs from damage
when used improperly.
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AC-COUPLED HEADPHONE OUTPUT
The circuit diagram below shows how to connect a stereo headphone to the WM9712L.
HPOUTL
C1 220uF
HPOUTR
WM9712L
C2 220uF
HPGND = 0V
Figure 25 Simple Headphone Output Circuit Diagram
The DC blocking capacitors C1 and C2 together with the load resistance determine the lower cut-off
frequency, fc. Increasing the capacitance lowers fc, improving the bass response. Smaller
capacitance values will diminish the bass response. For example, with a 16 load and C1 = 220F:
fc = 1 / 2 RLC1 = 1 / (2 x 16 x 220F) = 45 Hz
DC COUPLED (CAPLESS) HEADPHONE OUTPUT
In the interest of saving board space and cost, it may be desirable to eliminate the 220F DC blocking
capacitors. This can be achieved by using OUT3 as a headphone pseudo-ground, as shown below.
HPOUTL
WM9712L
HPOUTR
OUT3 = AVDD/2
Figure 26 Capless Headphone Output Circuit Diagram (OUT3SRC = 10)
As the OUT3 pin produces a DC voltage of AVDD/2, there is no DC offset between
HPOUTL/HPOUTR and OUT3, and therefore no DC blocking capacitors are required. However, this
configuration has some drawbacks:

w

The power consumption of the WM9712L is increased, due to the additional power
consumed in the OUT3 output buffer.
If the DC coupled output is connected to the line-in of a grounded piece of equipment,
then OUT3 becomes short-circuited. Although the built-in short circuit protection will
prevent any damage to the WM9712L, the audio signal will not be transmitted properly.

OUT3 cannot be used for another purpose
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BTL LOUDSPEAKER OUTPUT
LOUT2 and ROUT2 can differentially drive a mono 8 loudspeaker as shown below.
-1
LOUT2
Stereo: VSPKR = R-(-L) = L+R
LOUT2VOL
WM9712L
INV = 1
Mono: VSPKR = M-(-M) = 2M
ROUT2VOL
ROUT2
Figure 27 Speaker Output Connection (INV = 1)
The right channel is inverted by setting the INV bit, so that the signal across the loudspeaker is the
sum of left and right channels.
COMBINED HEADSET / BTL EAR SPEAKER
In smartphone applications with a loudspeaker and separate ear speaker (receiver), a BTL ear
speaker can be connected at the OUT3 pin, as shown below.
OUT3
BTL ear
speaker
HPOUTL
WM9712L
HPOUTR
HPGND = 0V
Figure 28 Combined Headset / BTL Ear Speaker (OUT3SRC = 00)
The ear speaker and the headset play the same signal. Whenever the headset is plugged in, the
headphone outputs are enabled and OUT3 disabled. When the headset is not plugged in, OUT3 is
enabled (see “Jack Insertion and Auto-Switching”)
COMBINED HEADSET / SINGLE-ENDED EAR SPEAKER
Instead of a BTL ear speaker, a single-ended ear speaker can also be used, as shown below.
OUT3
ear speaker
(single-ended)
HPOUTL
WM9712L
HPOUTR
HPGND = 0V
Figure 29 Combined Headset / Single-ended Ear Speaker (OUT3SRC = 01)
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JACK INSERT DETECTION
The circuit diagram below shows how to detect when a headphone or headset has been plugged into
the headphone socket. It generates an interrupt, instructing the controller to enable HPOUTL and
HPOUTR and disable OUT3.
+
DBVDD
-
+
HPOUTR
HPOUTL
-
L
100k
interrupt
logic
GPIO
R
switch closes
on insertion
Figure 30 Jack Insert Detection Circuit
The circuit requires a headphone socket with a switch that closes on insertion. It detects both
headphones and phone headsets. Any GPIO pin can be used, provided that it is configured as an
input.
HOOKSWITCH DETECTION
The circuit diagram below shows how to detect when the “hookswitch” of a phone headset is pressed
HPOUTR
HPOUTL
AGND
-
+
WM9712L
+
(pressing the hookswitch is equivalent to lifting the receiver in a stationary telephone).
-
MICL/MICR
interrupt
logic
L
R
MIC
GPIO
MICBIAS
680  2.2k
HOOK
SWITCH
47
PHONE HEADSET
Figure 31 Hookswitch Detection Circuit
The circuit uses a GPIO pin as a sense input. The impedance of the microphone and the resistor in
the MICBIAS path must be such that the potential at the GPIO pin is above 0.7DBVDD when the
hookswitch is open, and below 0.3DBVDD when it is closed.
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PACKAGE DRAWING
DM103.A
FL: 48 PIN QFN PLASTIC PACKAGE 7 X 7 X 0.9 mm BODY, 0.50 mm LEAD PITCH
D2
SEE DETAIL 1
D
D2/2
48
37
L
36
INDEX AREA
(D/2 X E/2)
1
EXPOSED
GROUND 6
PADDLE
E2/2
E2
E
SEE DETAIL 2
12
25
24
13
e
aaa C
2X
b
2X
BOTTOM VIEW
aaa C
TOP VIEW
ccc C
(A3)
A
0.08 C
SEATING PLANE
SIDE VIEW
A1
DETAIL 1
DETAIL 2
DETAIL 3
Datum
W
45°
T
(A3)
b
Exposed lead
EXPOSED
GROUND
PADDLE
Terminal
Tip
e/2
0.30mm
G
H
1
C
e
Half etch tie bar
DETAIL 3
Symbols
A
A1
A3
b
D
D2
E
E2
e
G
H
L
T
W
aaa
bbb
ccc
REF
Dimensions (mm)
NOM
MAX
0.90
1.00
0.05
0.02
0.20 REF
0.18
0.25
0.30
7.00 BSC
5.55
5.65
5.75
7.00 BSC
5.55
5.65
5.75
0.5 BSC
0.20
0.10
0.50
0.30
0.4
0.103
0.15
Tolerances of Form and Position
0.15
0.10
0.10
MIN
0.80
0
NOTE
1
JEDEC, MO-220, VARIATION VKKD-4
NOTES:
1. DIMENSION b APPLIED TO METALLIZED TERMINAL AND IS MEASURED BETWEEN 0.15 mm AND 0.30 mm FROM TERMINAL TIP.
2. ALL DIMENSIONS ARE IN MILLIMETRES
3. THE TERMINAL #1 IDENTIFIER AND TERMINAL NUMBERING CONVENTION SHALL CONFORM TO JESD 95-1 SPP-002.
4. COPLANARITY APPLIES TO THE EXPOSED HEAT SINK SLUG AS WELL AS THE TERMINALS.
5. THIS DRAWING IS SUBJECT TO CHANGE WITHOUT NOTICE.
6. REFER TO APPLICATION NOTE WAN_0118 FOR FURTHER INFORMATION REGARDING PCB FOOTPRINTS AND QFN PACKAGE SOLDERING.
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WM9712L
IMPORTANT NOTICE
Wolfson Microelectronics plc (“Wolfson”) products and services are sold subject to Wolfson’s terms and conditions of sale,
delivery and payment supplied at the time of order acknowledgement.
Wolfson warrants performance of its products to the specifications in effect at the date of shipment. Wolfson reserves the
right to make changes to its products and specifications or to discontinue any product or service without notice. Customers
should therefore obtain the latest version of relevant information from Wolfson to verify that the information is current.
Testing and other quality control techniques are utilised to the extent Wolfson deems necessary to support its warranty.
Specific testing of all parameters of each device is not necessarily performed unless required by law or regulation.
In order to minimise risks associated with customer applications, the customer must use adequate design and operating
safeguards to minimise inherent or procedural hazards. Wolfson is not liable for applications assistance or customer
product design. The customer is solely responsible for its selection and use of Wolfson products. Wolfson is not liable for
such selection or use nor for use of any circuitry other than circuitry entirely embodied in a Wolfson product.
Wolfson’s products are not intended for use in life support systems, appliances, nuclear systems or systems where
malfunction can reasonably be expected to result in personal injury, death or severe property or environmental damage.
Any use of products by the customer for such purposes is at the customer’s own risk.
Wolfson does not grant any licence (express or implied) under any patent right, copyright, mask work right or other
intellectual property right of Wolfson covering or relating to any combination, machine, or process in which its products or
services might be or are used. Any provision or publication of any third party’s products or services does not constitute
Wolfson’s approval, licence, warranty or endorsement thereof. Any third party trade marks contained in this document
belong to the respective third party owner.
Reproduction of information from Wolfson datasheets is permissible only if reproduction is without alteration and is
accompanied by all associated copyright, proprietary and other notices (including this notice) and conditions. Wolfson is
not liable for any unauthorised alteration of such information or for any reliance placed thereon.
Any representations made, warranties given, and/or liabilities accepted by any person which differ from those contained in
this datasheet or in Wolfson’s standard terms and conditions of sale, delivery and payment are made, given and/or
accepted at that person’s own risk. Wolfson is not liable for any such representations, warranties or liabilities or for any
reliance placed thereon by any person.
ADDRESS:
Wolfson Microelectronics plc
26 Westfield Road
Edinburgh
EH11 2QB
United Kingdom
Tel :: +44 (0)131 272 7000
Fax :: +44 (0)131 272 7001
Email :: [email protected]
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REVISION HISTORY
DATE
REV
ORIGINATOR
CHANGES
10/10/11
4.6
JMacD
Order codes updated from WM9712LGEFL/V and WM9712LGEFL/RV to
WM9712CLGEFL/V and WM9712CLGEFL/RV to reflect change to copper wire
bonding.
10/10/11
4.6
JMacD
Package Diagram updated to DM103.A
w
PD, Rev 4.6, November 2011
78