WM8581 [WOLFSON]
Multichannel CODEC with S/PDIF Transceiver; 多通道编解码器S / PDIF收发器
| 型号： | WM8581 |
| 厂家： | 
WOLFSON MICROELECTRONICS PLC |
| 描述： | Multichannel CODEC with S/PDIF Transceiver |
| 文件： | 总100页 (文件大小：1053K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
WM8581
w
Multichannel CODEC with S/PDIF Transceiver
DESCRIPTION
FEATURES
•
Multi-channel CODEC with 4 Stereo DACs and 1 Stereo
ADC
The WM8581 is a multi-channel audio CODEC with S/PDIF
transceiver. The WM8581 is ideal for DVD and surround
sound processing applications for home hi-fi, automotive
and other audiovisual equipment.
•
•
Integrated S/PDIF / IEC-60958-3 transceiver
Audio Performance
−
−
−
−
103dB SNR (‘A’ weighted @ 48kHz) DAC
-90dB THD (48kHz) DAC
Integrated into the device is a stereo 24-bit multi-bit sigma
delta ADC with support for digital audio output word lengths
from 16-bit to 32-bit, and sampling rates from 8kHz to
192kHz.
100dB SNR (‘A’ weighted @ 48kHz) ADC
-87dB THD (48kHz) ADC
Also included are four stereo 24-bit multi-bit sigma delta
•
•
•
•
DAC Sampling Frequency: 8kHz – 192kHz
ADC Sampling Frequency: 8kHz – 192kHz
Independent ADC and DAC Sample Rates
DACs, each with
a
dedicated oversampling digital
interpolation filter. Digital audio input word lengths from 16-
bits to 32-bits and sampling rates from 8kHz to 192kHz are
supported. Each DAC channel has independent digital
volume and mute control.
2 and 3-Wire Serial Control Interface with readback, or
Hardware Control Interface
•
•
GPO pins allow visibility of user selected status flags
Programmable Audio Data Interface Modes
Two independent audio data interfaces support I2S, Left
Justified, Right Justified and DSP digital audio formats.
Each audio interface can operate in either Master Mode or
Slave Mode.
−
−
I2S, Left, Right Justified or DSP
16/20/24/32 bit Word Lengths
•
Four independent stereo DAC outputs with independent
digital volume controls
The S/PDIF transceiver is IEC-60958-3 compatible and
supports frame rates from 32k/s to 96k/s. It has four
multiplexed inputs and one output. Status and error
monitoring is built-in and results can reported over the serial
interface or via GPO pins. S/PDIF Channel Block
configuration is also supported.
•
•
Two Independent Master or Slave Audio Data Interfaces
Flexible Digital Interface Routing with Clock Selection
Control
•
•
2.7V to 5.5V Analogue, 2.7V to 3.6V Digital Supply
Operation
The device has two PLLs that can be configured
independently to generate two system clocks for internal or
external use.
48-lead TQFP Package
Device control and setup is via a 2-wire or 3-wire (SPI
compatible) serial interface. The serial interface provides
access to all features including channel selection, volume
controls, mutes, de-emphasis, S/PDIF control/status, and
power management facilities. Alternatively, the device has a
Hardware Control Mode where device features can be
enabled/disabled using selected pins.
APPLICATIONS
•
•
•
•
Digital TV
DVD Players and Receivers
Surround Sound AV Processors and Hi-Fi systems
Automotive Audio
The device is available in a 48-lead TQFP package.
WOLFSON MICROELECTRONICS plc
Production Data, April 2007, Rev 4.0
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Copyright ©2007 Wolfson Microelectronics plc
WM8581
Production Data
BLOCK DIAGRAM
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WM8581
TABLE OF CONTENTS
DESCRIPTION............................................................................................................................................. 1
FEATURES .................................................................................................................................................. 1
APPLICATIONS ........................................................................................................................................... 1
BLOCK DIAGRAM....................................................................................................................................... 2
TABLE OF CONTENTS............................................................................................................................... 3
PIN CONFIGURATION ................................................................................................................................ 4
ORDERING INFORMATION........................................................................................................................ 4
PIN DESCRIPTION...................................................................................................................................... 5
MULTI-FUNCTION PINS .......................................................................................................................................... 6
ABSOLUTE MAXIMUM RATINGS.............................................................................................................. 8
RECOMMENDED OPERATING CONDITIONS .......................................................................................... 9
ELECTRICAL CHARACTERISTICS............................................................................................................ 9
TERMINOLOGY...................................................................................................................................................... 15
MASTER CLOCK TIMING ...................................................................................................................................... 15
DIGITAL AUDIO INTERFACE – MASTER MODE.................................................................................................. 16
DIGITAL AUDIO INTERFACE – SLAVE MODE ..................................................................................................... 17
CONTROL INTERFACE TIMING – 3-WIRE MODE ............................................................................................... 18
CONTROL INTERFACE TIMING – 2-WIRE MODE ............................................................................................... 18
DEVICE DESCRIPTION............................................................................................................................. 20
INTRODUCTION..................................................................................................................................................... 20
CONTROL INTERFACE OPERATION ................................................................................................................... 21
DIGITAL AUDIO INTERFACES.............................................................................................................................. 25
AUDIO DATA FORMATS........................................................................................................................................ 27
AUDIO INTERFACE CONTROL............................................................................................................................. 31
DAC FEATURES .................................................................................................................................................... 33
ADC FEATURES .................................................................................................................................................... 40
DIGITAL ROUTING OPTIONS................................................................................................................................ 41
CLOCK SELECTION .............................................................................................................................................. 43
PHASE-LOCKED LOOPS AND S/PDIF CLOCKING (SOFTWARE MODE) .......................................................... 49
PHASE-LOCKED LOOPS AND S/PDIF CLOCKING (HARDWARE MODE).......................................................... 57
S/PDIF TRANSCEIVER.......................................................................................................................................... 58
S/PDIF TRANSMITTER.......................................................................................................................................... 59
S/PDIF RECEIVER................................................................................................................................................. 62
POWERDOWN MODES......................................................................................................................................... 71
INTERNAL POWER ON RESET CIRCUIT............................................................................................................. 73
HARDWARE CONTROL MODE............................................................................................................................. 75
REGISTER MAP..................................................................................................................................................... 78
DIGITAL FILTER CHARACTERISTICS .................................................................................................... 94
DAC FILTER RESPONSES.................................................................................................................................... 94
DIGITAL DE-EMPHASIS CHARACTERISTICS...................................................................................................... 95
ADC FILTER RESPONSES.................................................................................................................................... 95
ADC HIGH PASS FILTER....................................................................................................................................... 96
APPLICATIONS INFORMATION............................................................................................................... 97
RECOMMENDED EXTERNAL COMPONENTS..................................................................................................... 97
PACKAGE DIMENSIONS.......................................................................................................................... 99
IMPORTANT NOTICE.............................................................................................................................. 100
ADDRESS:............................................................................................................................................................ 100
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PIN CONFIGURATION
ORDERING INFORMATION
PEAK
SOLDERING
TEMPERATURE
TEMPERATURE
MOISTURE
SENSITIVITY LEVEL
DEVICE
PACKAGE
RANGE
48-lead TQFP
(Pb-free)
WM8581AGEFT/V
WM8581AGEFT/RV
-25 to +85oC
MSL1
MSL1
260°C
260°C
48-lead TQFP
-25 to +85oC
(Pb-free, tape and reel)
Note:
Reel quantity = 2,200
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PIN DESCRIPTION
PIN
1
NAME
VOUT4L
VOUT4R
PGND
TYPE
DESCRIPTION
Analogue Output
Analogue Output
Supply
DAC channel 4 left output
DAC channel 4 right output
PLL ground
2
3
4
PVDD
Supply
PLL positive supply
Crystal or CMOS clock input
Crystal output
5
XTI
Digital Input
6
XTO
Digital Output
Digital Input/Output
Digital Input/Output
Digital Output
Digital Input/Output
Digital Input/Output
Digital Input/Output
Digital Input
7
MFP7
Multi-Function Pin (MFP) 7. See Table 1 for details of all MFP pins.
Multi-Function Pin (MFP) 6. See Table 1 for details of all MFP pins.
S/PDIF transmitter output
8
MFP6
9
SPDIFOP
MFP5
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
Multi-Function Pin (MFP) 5. See Table 1 for details of all MFP pins.
Multi-Function Pin (MFP) 4. See Table 1 for details of all MFP pins.
Multi-Function Pin (MFP) 3. See Table 1 for details of all MFP pins.
S/PDIF Receiver Input 1
MFP4
MFP3
SPDIFIN1
CLKOUT
DVDD
Digital Output
Supply
PLL or crystal oscillator clock output
Digital positive supply
DGND
Supply
Digital ground
MUTE
Digital Input/Output
Digital Input
DAC mute-all input/ All-DAC Infinite Zero Detect (IZD) flag output
Primary Audio Interface (PAIF) receiver data input 1
Primary Audio Interface (PAIF) receiver data input 2
Primary Audio Interface (PAIF) receiver data input 3
Primary Audio Interface (PAIF) receiver data input 4
Primary Audio Interface (PAIF) receiver left/right word clock
Primary Audio Interface (PAIF) receiver bit clock
System Master clock; 256, 384, 512, 768, 1024 or 1152 fs
Primary Audio Interface (PAIF) transmitter data output
Primary audio interface transmitter left/right word clock
Multi-Function Pin (MFP) 1. See Table 1 for details of all MFP pins.
Multi-Function Pin (MFP) 2. See Table 1 for details of all MFP pins.
Configures control to be either Software Mode or Hardware Mode
Configures software interface to be either 2-wire or 3-wire. See note 2.
3-wire control interface data output. See note 3.
Control interface data input (and output under 2-wire control)
Control interface clock
DIN1
DIN2
Digital Input
DIN3
Digital Input
DIN4
Digital Input
PAIFRX_LRCLK
PAIFRX_BCLK
MCLK
Digital Input/Output
Digital Input/Output
Digital Input/Output
Digital Output
Digital Input/Output
Digital Input/Output
Digital Input/Output
Digital Input
DOUT
PAIFTX_LRCLK
MFP1
MFP2
HWMODE
SWMODE
SDO
Digital Input/Output
Digital Output
Digital Input/Output
Digital Input
SDIN
SCLK
CSB
Digital Input
3-wire control interface latch signal / device address selection
ADC Right Channel Input
AINR
Analogue Input
Analogue Input
Analogue Output
Analogue Output
Supply
AINL
ADC Left Channel Input
ADCREFP
VMID
ADC reference buffer decoupling pin; 10uF external decoupling
Midrail divider decoupling pin; 10uF external decoupling
Analogue ground
AGND
AVDD
Supply
Analogue positive supply
VOUT1L
VOUT1R
VOUT2L
VOUT2R
VREFP
VREFN
Analogue Output
Analogue Output
Analogue Output
Analogue Output
Analogue Input
Analogue Input
DAC channel 1 left output
DAC channel 1 right output
DAC channel 2 left output
DAC channel 2 right output
DAC and ADC positive reference
DAC and ADC ground reference
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PIN
47
NAME
VOUT3L
VOUT3R
TYPE
DESCRIPTION
Analogue Output
Analogue Output
DAC channel 3 left output
DAC channel 3 right output
48
Notes :
1. Digital input pins have Schmitt trigger input buffers. Pins 32, 33, 34 are 5V tolerant.
2. In hardware control mode, pin 30 is used for UNLOCK flag output.
3. In hardware control mode, pin 31 is used for NON_AUDIO flag output.
MULTI-FUNCTION PINS
The WM8581 has 7 Multi-Function Input/Output pins (MFP1 etc.). The function and direction (input/output) of these pins
reconfigured using the HWMODE input pin and software register control as shown below. If HWMODE is set, the MFPs have the
function shown in column 1 of Table 1. If HWMODE is not set, and the register SAIF_EN is set, the MFPs have the function shown
in column 2. Otherwise, the GPOnOP registers determine the MFP function as shown in columns 3 and 4.
N
Y
HWMODE = 1
Y
N
SAIF_EN = 1
GPIOnOP
PIN NAME
HARDWARE
CONTROL MODE
FUNCTION
SECONDARY AUDIO
INTERFACE FUNCTION
S/PDIF INPUT &
INDEPENDENT
CLOCKING
GENERAL PURPOSE
OUTPUT FUNCTION
2
4
1
PAIFTX_BCLK
ADCMCLK
DR1
3
MFP1
MFP2
MFP3
MFP4
MFP5
MFP6
MFP7
n/a1
n/a1
n/a1
PAIFTX_BCLK2
ADCMCLK3
SPDIFIN2
SPDIFIN3
SPDIFIN4
GPO6
GPO1
GPO2
GPO3
GPO4
GPO5
GPO6
GPO7
DR2
SAIF_DIN
SAIF_DOUT
SAIF_BCLK
SAIF_LRCLK
DR3
DR4
ALLPD
GPO7
Table 1 Multi-Function Pin Configuration
Notes:
1. These pins are not used as part of the Secondary Audio Interface, so their function is that of either Column 3 or Column 4.
2. MFP1 can by GPO1 only if ADC_CLKSEL and PAIFTXMS_CLKSEL (if in master mode) source MCLK.Note that by default
ADC_CLKSEL sources ADCMCLK pin.
3. MFP2 can be GPO2 if neither ADC_CLKSEL, TX_CLKSEL or SAIFMS_CLKSEL (if in master mode) source ADCMCLK.Note
that by default all three ADC_CLKSEL sources ADCMCLK pin.
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PIN FUNCTION
PAIFTX_BCLK
ADCMCLK
TYPE
Digital Input/Output
Digital Input
DESCRIPTION
Primary Audio Interface Transmitter (PAIFTX) Bit Clock
Master ADC clock; 256fs, 384fs, 512fs ,786fs, 1024fs or 1152fs
Secondary Audio Interface (SAIF) Receiver data input
Secondary Audio Interface (SAIF) Transmitter data output
Secondary Audio Interface (SAIF) Bit Clock
Secondary Audio Interface (SAIF) Left/Right Word Clock
S/PDIF Receiver Input
SAIF_DIN
Digital Input
SAIF_DOUT
SAIF_BCLK
SAIF_LRCLK
SPDIFIN2/3/4
GPO1 - GPO7
DR1/2/3/4
Digital Output
Digital Input/Output
Digital Input/Output
Digital Input
Digital Output
Digital Input
General Purpose Output
Internal Digital Routing Configuration in Hardware Mode
Chip Powerdown in Hardware Mode
ALLPD
Digital Input
Table 2 Multi-Function Pin Description
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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.
The WM8581 has been classified as MSL1, which has an unlimited floor life at <30oC / 85% Relative Humidity and therefore will
not be supplied in moisture barrier bags.
CONDITION
MIN
MAX
Digital supply voltage
-0.3V
+3.63V
Analogue supply voltage
-0.3V
-0.3V
+7V
+5V
+7V
PLL supply voltage
Voltage range digital inputs (SCLK, CSB & SDIN only)
DGND -0.3V
Voltage range digital inputs
DGND -0.3V
DVDD + 0.3V
Voltage range analogue inputs 1
AGND -0.3V
PGND -0.3V
AVDD +0.3V
PVDD +0.3V
37MHz
Master Clock Frequency
Operating temperature range, TA
-25°C
+85°C
Storage temperature prior to soldering
Storage temperature after soldering
30°C max / 85% RH max
-65°C
+150°C
+260°C
+183°C
Pb Free Package body temperature (soldering 10 seconds)
Package body temperature (soldering 2 minutes)
Notes: 1. Analogue and digital grounds must always be within 0.3V of each other.
Table 3 Absolute Maximum Ratings
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RECOMMENDED OPERATING CONDITIONS
PARAMETER
SYMBOL
DVDD
TEST CONDITIONS
MIN
2.7
2.7
3.3
TYP
MAX
3.6
UNIT
Digital supply range
Analogue supply range
PLL supply range
Ground
V
V
V
V
AVDD
5.5
PVDD
5.5
AGND, VREFN, DGND.
PGND
0
0
Difference DGND to
AGND/PGND
-0.3
+0.3
V
Note: Digital supply DVDD must never be more than 0.3V greater than AVDD.
Table 4 Recommended Operating Conditions
ELECTRICAL CHARACTERISTICS
Test Conditions
AVDD, PVDD, VREFP = 5V, DVDD = 3.3V, AGND, VREFN = 0V, PGND, DGND = 0V, TA = +25oC, 1kHz Signal, fs = 48kHz,
24-Bit Data, Slave Mode, MCLK, ADCMCLK = 256fs, 1Vrms Input Signal Level unless otherwise stated.
PARAMETER
SYMBOL
TEST CONDITIONS
MIN
TYP
MAX
UNIT
Vrms
dB
DAC Performance (Load = 10kΩ, 50pF)
0dBFs Full scale output voltage
1.0xVREFP/5
103
Signal to Noise Ratio (See
Terminology note 1,2,4)
SNR
95
A-Weighted
@ fs = 48kHz
Unweighted,
@ fs = 48kHz
100
99
dB
dB
A-Weighted
@ fs = 48kHz, AVDD =
3.3V
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Test Conditions
AVDD, PVDD, VREFP = 5V, DVDD = 3.3V, AGND, VREFN = 0V, PGND, DGND = 0V, TA = +25oC, 1kHz Signal, fs = 48kHz,
24-Bit Data, Slave Mode, MCLK, ADCMCLK = 256fs, 1Vrms Input Signal Level unless otherwise stated.
PARAMETER
SYMBOL
TEST CONDITIONS
MIN
TYP
MAX
UNIT
101
dB
A-Weighted
@ fs = 96kHz
Unweighted,
@ fs = 96kHz
98
99
dB
dB
A-Weighted
@ fs = 96kHz, AVDD =
3.3V
101
dB
A-Weighted
@ fs = 192kHz
Unweighted,
98
99
dB
dB
@ fs = 192kHz
A-Weighted
@ fs = 192kHz, AVDD
= 3.3V
Dynamic Range (See
Terminology note 2,4)
DNR
THD
A-weighted, -60dB full
scale input
95
103
-90
dB
dB
Total Harmonic Distortion
1kHz, 0dB Full Scale @
fs = 48kHz
-85
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Test Conditions
AVDD, PVDD, VREFP = 5V, DVDD = 3.3V, AGND, VREFN = 0V, PGND, DGND = 0V, TA = +25oC, 1kHz Signal, fs = 48kHz,
24-Bit Data, Slave Mode, MCLK, ADCMCLK = 256fs, 1Vrms Input Signal Level unless otherwise stated.
PARAMETER
SYMBOL
TEST CONDITIONS
MIN
TYP
MAX
UNIT
1kHz, 0dB Full Scale @
fs = 96kHz
-87
dB
1kHz, 0dB Full Scale @
fs = 192kHz
-84
dB
DAC Channel separation
Mute Attenuation
100
100
2
dB
dB
1kHz Input, 0dB gain
Output Offset Error
mV
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Test Conditions
AVDD, PVDD, VREFP = 5V, DVDD = 3.3V, AGND, VREFN = 0V, PGND, DGND = 0V, TA = +25oC, 1kHz Signal, fs = 48kHz,
24-Bit Data, Slave Mode, MCLK, ADCMCLK = 256fs, 1Vrms Input Signal Level unless otherwise stated.
PARAMETER
SYMBOL
TEST CONDITIONS
1kHz 100mVp-p
20Hz to 20kHz
100mVp-p
MIN
TYP
50
MAX
UNIT
dB
Power Supply Rejection Ratio
(See note 4)
PSRR
45
dB
ADC Performance
Full Scale Input Signal Level (for
ADC 0dB Input)
Vrms
1.0xVREFP/5
Input resistance
6
kΩ
pF
dB
Input capacitance
10
Signal to Noise Ratio (See
Terminology note 1,2,4)
SNR
90
100
A-Weighted
@ fs = 48kHz
Unweighted,
@ fs = 48kHz
97
97
dB
dB
A-Weighted
@ fs = 48kHz, AVDD =
3.3V
97
dB
A-Weighted
@ fs = 96kHz
Unweighted,
@ fs = 96kHz
94
94
dB
dB
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Test Conditions
AVDD, PVDD, VREFP = 5V, DVDD = 3.3V, AGND, VREFN = 0V, PGND, DGND = 0V, TA = +25oC, 1kHz Signal, fs = 48kHz,
24-Bit Data, Slave Mode, MCLK, ADCMCLK = 256fs, 1Vrms Input Signal Level unless otherwise stated.
PARAMETER
SYMBOL
TEST CONDITIONS
MIN
TYP
MAX
UNIT
A-Weighted
@ fs = 96kHz, AVDD =
3.3V
97
dB
A-Weighted
@ fs = 192kHz
Unweighted,
94
94
dB
dB
@ fs = 192kHz
A-Weighted
@ fs = 192kHz, AVDD
= 3.3V
Total Harmonic Distortion
THD
DNR
1kHz, -1dB Full Scale
@ fs = 48kHz
-87
-86
-85
-80
dB
dB
dB
1kHz, -1dB Full Scale
@ fs = 96kHz
1kHz, -1dB Full Scale
@ fs = 192kHz
Dynamic Range
-60dB FS
1kHz Input
1KHz Signal
90
100
97
ADC Channel Separation
dB
dB
Channel Level Matching (See
Terminology note 4)
0.1
Channel Phase Deviation
Offset Error
1kHz Signal
HPF On
0.0001
0
Degree
LSB
HPF Off
100
LSB
Digital Logic Levels (CMOS Levels)
Input LOW level
VIL
VIH
0.3 x DVDD
+1
V
V
Input HIGH level
0.7 x DVDD
-1
Input leakage current
Input capacitance
±0.2
5
µA
pF
V
Output LOW
VOL
VOH
I
OL=1mA
0.1 x DVDD
Output HIGH
I
OH= -1mA
0.9 x DVDD
V
Analogue Reference Levels
Reference voltage
VVMID
VREFP/2 –
50mV
VREFP/2
VREFP/2 +
50mV
V
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Test Conditions
AVDD, PVDD, VREFP = 5V, DVDD = 3.3V, AGND, VREFN = 0V, PGND, DGND = 0V, TA = +25oC, 1kHz Signal, fs = 48kHz,
24-Bit Data, Slave Mode, MCLK, ADCMCLK = 256fs, 1Vrms Input Signal Level unless otherwise stated.
PARAMETER
SYMBOL
TEST CONDITIONS
MIN
TYP
MAX
UNIT
Potential divider resistance
RVMID
VREFP to VMID and
VMID to VREFN
14
kΩ
VMIDSEL = 1
VREFP to VMID and
VMID to VREFN
44
50
kΩ
VMIDSEL = 0
S/PDIF Transceiver Performance
Jitter on recovered clock
S/PDIF Input Levels CMOS MODE
Input LOW level
ps
VIL
VIH
0.3 X DVDD
36
V
V
Input HIGH level
0.7 X DVDD
Input capacitance
1.25
pF
Input Frequency
MHz
S/PDIF Input Levels Comparator MODE
Input capacitance
Input resistance
Input frequency
Input Amplitude
PLL
10
23
pF
kΩ
25
MHz
mV
200
0.5 X DVDD
Period Jitter
XTAL
80
ps(rms)
Input XTI LOW level
Input XTI HIGH level
Input XTI capacitance
Input XTI leakage
VXIL
0
557
mV
mV
pF
VXIH
CXJ
853
3.32
28.92
86
4.491
38.96
278
IXleak
VXOL
VXOH
mA
mV
V
Output XTO LOW
Output XTO HIGH
Supply Current
15pF load capacitors
15pF load capacitors
1.458
1.942
Analogue supply current
Analogue supply current
Digital supply current
Power Down
AVDD, VREFP = 5V
AVDD, VREFP = 3.3V
DVDD = 3.3V
45
30
mA
mA
mA
µA
25
500
Table 5 Electrical Characteristics
Notes:
1. Ratio of output level with 1kHz full scale input, to the output level with all zeros into the digital input, measured ‘A’ weighted.
2. All performance measurements done with 20kHz low pass filter, and where noted an A-weight filter. Failure to use such a filter
will result in higher THD+N and lower SNR and Dynamic Range readings than are found in the Electrical Characteristics. The
low pass filter removes out of band noise; although it is not audible it may affect dynamic specification values.
3. VMID decoupled with 10uF and 0.1uF capacitors (smaller values may result in reduced performance).
4. PSSR measured with VMID set to high impedance
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TERMINOLOGY
1. Signal-to-noise ratio (dB) – SNR is a measure of the difference in level between the full scale output and the output with no
signal applied. (No Auto-zero or Automute function is employed in achieving these results).
2. Dynamic range (dB) – DNR is a measure of the difference between the highest and lowest portions of a signal. Normally a
THD+N measurement at 60dB below full scale. The measured signal is then corrected by adding the 60dB to it. (e.g. THD+N
@ -60dB= -32dB, DR= 92dB).
3. THD (dB) – THD is a ratio, of the rms values, of Distortion/Signal.
4. Stop band attenuation (dB) – Is the degree to which the frequency spectrum is attenuated (outside audio band).
5. Channel Separation (dB) – Also known as Cross-Talk. This is a measure of the amount one channel is isolated from the
other. Normally measured by sending a full scale signal down one channel and measuring the other.
6. Pass-Band Ripple – Any variation of the frequency response in the pass-band region.
MASTER CLOCK TIMING
tMCLKL
ADCMCLK/
MCLK
tMCLKH
tMCLKY
Figure 1 Master Clock Timing Requirements
Test Conditions
AVDD, PVDD, VREFP = 5V, DVDD = 3.3V, AGND, VREFN = 0V, PGND, DGND = 0V, TA = +25oC
PARAMETER
SYMBOL
TEST CONDITIONS
MIN
TYP
MAX
UNIT
System Clock Timing Information
ADCMCLK and MCLK System clock
pulse width high
tMCLKH
tMCLKL
tMCLKY
11
11
ns
ns
ns
ADCMCLK and MCLK System clock
pulse width low
ADCMCLK and MCLK System clock
cycle time
28
ADCMCLK and MCLK Duty cycle
40:60
60:40
Table 3 Master Clock Timing Requirements
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DIGITAL AUDIO INTERFACE – MASTER MODE
PAIFRX_BCLK/
PAIFTX_BCLK/
SAIF_BCLK
(Output)
tDL
PAIFRX_LRCLK/
PAIFTX_LRCLK/
SAIF_LRCLK
(Outputs)
tDDA
DOUT/
SAIF_DOUT
DIN1/2/3/4
SAIF_DIN
tDST
tDHT
Figure 2 Digital Audio Data Timing – Master Mode
Test Conditions
AVDD, PVDD, VREFP = 5V, DVDD = 3.3V, AGND, VREFN, PGND, DGND = 0V, TA = +25oC, Master Mode, fs = 48kHz, MCLK
and ADCMCLK = 256fs unless otherwise stated.
PARAMETER
SYMBOL
TEST CONDITIONS
MIN
TYP
MAX
UNIT
Audio Data Input Timing Information
PAIFTX_LRCLK/
PAIFRX_LRCLK/
tDL
0
10
ns
SAIF_LRCLK propagation
delay from PAIFTX_BCLK/
PAIFRX_BCLK/
SAIF_BCLK falling edge
DOUT/SAIF_DOUT
propagation delay from
PAIFTX_BCLK/
tDDA
tDST
tDHT
0
10
ns
ns
ns
SAIF_BCLK falling edge
DIN1/2/3/4/SAIF_DIN setup
time to
PAIFRX_BCLK/SAIF_BCLK
rising edge
10
10
DIN1/2/3/4/SAIF_DIN hold
time from
PAIFRX_BCLK/SAIF_BCLK
rising edge
Table 4 Digital Audio Data Timing – Master Mode
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DIGITAL AUDIO INTERFACE – SLAVE MODE
Figure 3 Digital Audio Data Timing – Slave Mode
Test Conditions
AVDD, PVDD = 5V, DVDD = 3.3V, AGND = 0V, PGND,DGND = 0V, TA = +25oC, Slave Mode, fs = 48kHz, MCLK and
ADCMCLK = 256fs unless otherwise stated.
PARAMETER
SYMBOL
TEST CONDITIONS
MIN
TYP
MAX
UNIT
Audio Data Input Timing Information
PAIFTX_BCLK/
tBCY
50
ns
PAIFRX_BCLK/SAIF_BCLK cycle
time
PAIFTX_BCLK/
tBCH
20
20
10
ns
ns
ns
PAIFRX_BCLK/SAIF_BCLK pulse
width high
PAIFTX_BCLK/
tBCL
PAIFRX_BCLK/SAIF_BCLK pulse
width low
PAIFTX_LRCLK/
tLRSU
PAIFRX_LRCLK/SAIF_BCLK set-up
time to PAIFTX_BCLK/
PAIFRX_BCLK/SAIF_BCLK rising
edge
PAIFTX_LRCLK/
PAIFRX_LRCLK/
tLRH
10
ns
SAIF_LRCLK hold time from
PAIFTX_BCLK/
PAIFRX_BCLK/SAIF_BCLK rising
edge
DIN1/2/3/4/SAIF_DIN set-up time to
PAIFRX_BCLK/
tDS
10
ns
SAIF_BCLK rising edge
DIN1/2/3/4/SAIF_DIN hold time
from PAIFRX_BCLK/SAIF_BCLK
rising edge
tDH
10
0
ns
ns
DOUT/SAIF_DOUT propagation
delay from
tDD
10
PAIFTX_BCLK/SAIF_BCLK falling
edge
Table 5 Digital Audio Data Timing – Slave Mode
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CONTROL INTERFACE TIMING – 3-WIRE MODE
t
t
CSS
CSH
CSB
t
t
t
SCY
SCS
CSS
SCLK
SDIN
LSB
t
t
t
DSU
DHO
DL
LSB
SDO
Figure 4 SPI Compatible Control Interface Input Timing
Test Conditions
AVDD, PVDD = 5V,DVDD = 3.3V, AGND, PGND,DGND = 0V, TA = +25oC, fs = 48kHz, MCLK and ADCMCLK = 256fs unless
otherwise stated
PARAMETER
SCLK rising edge to CSB rising edge
SCLK pulse cycle time
SYMBOL
tSCS
MIN
60
TYP
MAX
60/40
5
UNIT
ns
tSCY
80
ns
SCLK duty cycle
40/60
20
ns
SDIN to SCLK set-up time
SDIN hold time from SCLK rising edge
tDSU
tDHO
tDL
ns
20
ns
SDO propagation delay from SCLK rising
edge
ns
CSB pulse width high
tCSH
tCSS
tps
20
20
2
ns
ns
ns
CSB rising/falling to SCLK rising
SCLK glitch suppression
8
Table 6 3-wire SPI Compatible Control Interface Input Timing Information
CONTROL INTERFACE TIMING – 2-WIRE MODE
t
3
t
t
3
5
SDIN
SCLK
t
t
t
t
6
2
4
8
t
t
t
7
9
1
Figure 5 Control Interface Timing – 2-Wire Serial Control Mode
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Test Conditions
AVDD, PVDD = 5V,DVDD = 3.3V, AGND, PGND,DGND = 0V, TA = +25oC, fs = 48kHz, MCLK and ADCMCLK = 256fs unless
otherwise stated
PARAMETER
SYMBOL
MIN
TYP
MAX
UNIT
Program Register Input Information
SCLK Frequency
0
526
kHz
us
ns
ns
ns
ns
ns
ns
ns
ns
ns
SCLK Low Pulse-Width
SCLK High Pulse-Width
Hold Time (Start Condition)
Setup Time (Start Condition)
Data Setup Time
t1
t2
t3
t4
t5
t6
t7
t8
t9
tps
1.3
600
600
600
100
SDIN, SCLK Rise Time
SDIN, SCLK Fall Time
Setup Time (Stop Condition)
Data Hold Time
300
300
600
0
900
5
SCLK glitch suppression
Table 7 2-Wire Control Interface Timing Information
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DEVICE DESCRIPTION
INTRODUCTION
WM8581 is a complete mutli-channel CODEC with integrated S/PDIF transceiver. The device
comprises four separate stereo DACs and a stereo ADC, in a single package, and controlled by
either software or hardware interfaces.
The four stereo DAC outputs are ideal to implement a complete 7.1 channel surround system. Each
DAC has its own digital volume control (adjustable in 0.5dB steps) with zero cross detection. With
zero cross enabled, volume updates occur as a signal transitions through its zero point. This
minimises audible clicks and ‘zipper’ noise as the gain values change.
Each stereo DAC has its own data input (DIN1/2/3/4) and shared word clock (PAIFRX_LRCLK), bit
clock (PAIFRX_BCLK) and master clock (MCLK). The stereo ADC has data output (DOUT), word
clock (PAIFTX_LRCLK), and bit clock (PAIFTX_BCLK). This allows the ADC to operate at a different
sample rate to the DACs. In addition, a separate ADC master clock (ADCMCLK) can be used instead
of MCLK for further flexibility.
There are two independent Digital Audio Interfaces, which may be configured to operate in either
master or slave mode. In Slave mode, the LRCLKs and BCLKs are inputs. In Master mode, the
LRCLKs and BCLKs are outputs.
The Audio Interfaces support Right Justified, Left Justified, I2S and DSP formats. Word lengths of 16,
20, 24 and 32 bits are available (with the exception of 32 bit Right Justified).
Operation using system clocks of 128fs, 192fs, 256fs, 384fs, 512fs, 768fs or 1152fs is provided. In
Slave mode, selection between clock rates is automatically controlled. In master mode, the master
clock to sample rate ratio is set by register control. Sample rates (fs) from less than 8ks/s up to
192ks/s are permitted providing the appropriate system clock is input.
The S/PDIF Transceiver is IEC-60958-3 compatible with 32k frames/s to 96k frames/s support.
S/PDIF data can be input on one of four pins, and routed internally to the Audio Interfaces, DAC1,
and S/PDIF transmitter. Error flags and status information can be read back over the serial interface,
or output on GPO pins. The S/PDIF Transmitter can source data from the ADC, S/PDIF Receiver or
Audio Interfaces. The Transceiver supports Consumer Mode Channel information, and transmitted
Channel bits can be configured via register control.
The Digital Routing paths between all the interfaces can be configured by the user, as can the
corresponding interface clocking schemes.
There are two PLLs, which can be independently configured to generate two system clocks for
internal or external use.
The serial control interface is controlled by pins CSB, SCLK, and SDIN, which are 5V tolerant with
TTL input thresholds, allowing the WM8581 to be used with DVDD = 3.3V and be controlled by a
controller with 5V output.
The WM8581 may also be controlled in hardware mode, selected by the HWMODE pin. In hardware
mode, limited control of internal functionality is available via the Multi-Function Pins (MFPs) and CSB,
SCLK, SDIN and MUTE pins.
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CONTROL INTERFACE OPERATION
Control of the WM8581 is implemented either in Hardware Control Mode or Software Control Mode.
The method of control is determined by the state of the HWMODE pin. If the HWMODE pin is low,
Software Control Mode is selected. If the HWMODE pin is high, Hardware Control Mode is selected.
The Software Control Interface is described below and Hardware Control Mode is described on page
75.
Software control is implemented with a 3-wire (3-wire write, 4-wire read, SPI compatible) or 2-wire (2-
wire write, 2-wire read) serial interface.
The interface configuration is determined by the state of the SWMODE pin. If the SWMODE pin is
low, the 2-wire configuration is selected. If SWMODE is high the 3-wire SPI compatible configuration
is selected.
HWMODE
SWMODE
0
1
0
1
Software Control Hardware Control 2-wire control
3-wire control
Table 8 Hardware/Software Mode Setup
The control interface is 5V tolerant, meaning that the control interface input signals CSB, SCLK and
SDIN may have an input high level of 5V while DVDD is 3V. Input thresholds are determined by
DVDD.
3-WIRE (SPI COMPATIBLE) SERIAL CONTROL MODE WITH READ-BACK
SDIN is used to program data, SCLK is used to clock in the program data and CSB is used to latch
the program data. SDIN is sampled on the rising edge of SCLK. The 3-wire interface write protocol is
shown in Figure 6.
Figure 6 3-Wire SPI Compatible Interface
1. A[6:0] are Control Address Bits
2. D[8:0] are Control Data Bits
3. CSB is edge sensitive – the data is latched on the rising edge of CSB.
REGISTER READ-BACK
The read-only status registers can be read back via the SDO pin. To enable readback the READEN
control register bit must be set. The status registers can then be read using one of two methods,
selected by the CONTREAD register bit.
With CONTREAD set, a single read-only register can be read back by writing to any other register or
to a dummy register. The register to be read is determined by the READMUX[2:0] bits. When a write
to the device is performed, the device will respond by returning the status byte in the register selected
by the READMUX register bits. This 3-wire interface read back method using a write access is shown
in.Figure 7
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DESCRIPTION
REGISTER ADDRESS
BIT
LABEL
READMUX
[2:0]
DEFAULT
R52
READBACK
34h
2:0
000
Determines which status register
is to be read back:
000 = Error Register
001 = Channel Status Register 1
010 = Channel Status Register 2
011 = Channel Status Register 3
100 = Channel Status Register 4
101 = Channel Status Register 5
110 = S/PDIF Status Register
Continuous Read Enable.
3
4
CONTREAD
READEN
0
0
0 = Continuous read-back mode
disabled
1 = Continuous read-back mode
enabled
Read-back mode enable.
0 = read-back mode disabled
1 = read-back mode enabled
Table 9 Read-back Control Register
The 3-wire interface readback protocol is shown below. Note that the SDO pin is tri-state unless CSB
is held low; therefore CSB must be held low for the duration of the read.
Figure 7 3-Wire SPI Compatible Interface Continuous Readback
If CONTREAD is set to zero, the user can read back directly from the register by writing to the
register address, to which the device will respond with data. The protocol for this system is shown in
Figure 8 below.
Figure 8 3-Wire SPI Compatible Control Interface Non-Continuous Readback
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2-WIRE SERIAL CONTROL MODE WITH READ-BACK
The WM8581 supports software control via a 2-wire read/write serial bus. Many devices can be
controlled by the same bus, and each device has a unique 7-bit address (see Table 10).
The controller indicates the start of data transfer with a high to low transition on SDIN while SCLK
remains high. This indicates that a device address, DEVA(7:1), and data REG(6:0) will follow. All
devices on the 2-wire bus respond to the start condition and shift in the next eight bits on SDIN (7-bit
address + Read/Write bit, MSB first). If the device address received matches the address of the
WM8581, the WM8581 responds by pulling SDIN low on the next clock pulse (ACK). If the address is
not recognised, the WM8581 returns to the idle condition and wait for a new start condition and valid
address.
Once the WM8581 has acknowledged a correct address, the controller sends the first byte of control
data (REGA(6:0), i.e. the WM8581 register address plus the first bit of register data). The WM8581
then acknowledges the first data byte by pulling SDIN low for one clock pulse. The controller then
sends the second byte of control data (DIN(7:0), i.e. the remaining 8 bits of register data), and the
WM8581 acknowledges by driving SDIN low.
The transfer of data is complete when there is a low to high transition on SDIN while SCLK is high.
After receiving a complete address and data sequence the WM8581 returns to the idle state and
waits for another start condition. If a start or stop condition is detected out of sequence at any point
during data transfer (i.e. SDIN changes while SCLK is high), the device returns to the idle condition.
Figure 9 2-Wire Serial Control Interface
The WM8581 has two possible device addresses, which can be selected using the CSB pin.
CSB STATE
DEVICE ADDRESS IN 2-
WIRE MODE
ADDRESS (X=R/W BIT)
X=0
0x34
0x36
X= 1
0x35
0x37
Low or Unconnected
High
0011010x
0011011x
Table 10 2-Wire MPU Interface Address Selection
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REGISTER READBACK
The WM8581 allows readback of certain registers in 2-wire mode. As in 3-wire mode, there are two
methods of reading back data: continuous and non-continuous readback. Continuous readback is set
by writing to the Readback Control register (see Table 9) to set READEN and CONTREAD to 1, and
to set the READMUX bits to select the register to be read back. The status of this register can then
be readback using the protocol shown in Figure 10.
Figure 10 2-Wire Continuous Readback
If CONTREAD is set to zero, the user can read back directly from the register by writing to the
register address, to which the device will respond with data. The protocol for this system is shown in
Figure 11.
Figure 11 2-Wire Non-Continuous Readback
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SOFTWARE REGISTER RESET
Writing to register R53 will cause a register reset, resetting all register bits to their default values.
Note that the WM8581 is powered down by default so writing to this register will power down the
device.
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
R53
RESET
35h
8:0
RESET
n/a
Writing any data value to this register
will apply a reset to the device
registers.
Table 11 Software Reset
DIGITAL AUDIO INTERFACES
Audio data is transferred to and from the WM8581 via the Digital Audio Interfaces. There are two
Receive Audio Interfaces and two Transmit Audio Interfaces. The Digital Routing options for these
interfaces are described on page 24. Control of the audio interfaces is described below.
MASTER AND SLAVE MODES
The Audio Interfaces require both a left-right-clock (LRCLK) and a bit-clock (BCLK). These can be
supplied externally (slave mode) or they can be generated internally (master mode). When in master
mode, the BCLKs and LRCLKs for an interface are output on the corresponding BCLK and LRCLK
pins. By default, all interfaces operate in slave mode, but can operate in master mode by setting the
PAIFTXMS, PAIFRXMS, SAIFMS register bits. In Hardware Control Mode, the PAIF Transmitter can
operate in master mode by setting the SDI pin.
Figure 12 Slave Mode
Figure 13 Master Mode
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REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
R9
5
PAIFRX
MS
0
PAIF Rx Master/Slave Mode Select:
0 = Slave Mode
1 = Master Mode
5
5
PAIFTX
MS
0
0
PAIF Tx Master/Slave Mode Select:
0 = Slave Mode
R10
R11
1 = Master Mode
SAIFMS
SAIF Master/Slave Mode Select:
0 = Slave Mode
1 = Master Mode
Table 12 Master Mode Registers
The frequency of a master mode LRCLK is dependant on system clock and the RATE register control
bits. Table 27 shows the settings for common sample rates and system clock frequencies.
SAMPLING RATE
MCLK CLOCK FREQUENCY (MHZ)
(LRCLK)
128fs
RATE =000
4.096
192fs
RATE =001
6.144
256fs
RATE =010
8.192
384fs
RATE =011
12.288
512fs
RATE =100
16.384
768fs
RATE =101
24.576
1152fs
RATE =110
36.864
32kHz
44.1kHz
48kHz
5.6448
6.144
8.467
11.2896
12.288
16.9344
18.432
22.5792
24.576
33.8688
36.864
Unavailable
Unavailable
9.216
88.2kHz
96kHz
11.2896
12.288
22.5792
24.576
16.9344
18.432
33.8688
36.864
22.5792
24.576
33.8688
36.864
Unavailable Unavailable Unavailable
Unavailable Unavailable Unavailable
176.4kHz
192kHz
Unavailable Unavailable Unavailable Unavailable Unavailable
Unavailable Unavailable Unavailable Unavailable Unavailable
Table 13 Master Mode MCLK / LRCLK Frequency Selection
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
R9
PAIF 1
09h
2:0
PAIFRX_RATE
[2:0]
010
Master Mode MCLK/LRCLK
Ratio:
000 = 128fs
001 = 192fs
010 = 256fs
011 = 384fs
100 = 512fs
101 = 768fs
110 = 1152fs
R10
2:0
2:0
PAIFTX_RATE
[2:0]
010
010
PAIF 2
0Ah
R11
SAIF_RATE
[2:0]
SAIF 1
0Bh
Table 14 Master Mode RATE Registers
In master mode, the BCLKSEL register controls the number of BCLKs per LRCLK. If the
MCLK:LRCLK ratio is 128fs or 192fs and BCLKSEL = 10, BCLKSEL is overwritten to be 128
BCLKs/LRCLK. Also, if BCLKSEL = 00, and LRCLK is 192fs or 1152fs, the generated BCLK has a
mark-space ratio of 1:2.
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REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
R9
PAIF 1
09h
4:3
PAIFRX_BCLKSEL
[1:0]
00
Master Mode BCLK Rate:
00 = 64 BCLKs per LRCLK
01 = 32 BCLKs per LRCLK
10 = 16 BCLKs per LRCLK
11 = BCLK = System Clock.
R10
4:3
4:3
PAIFTX_BCLKSEL
[1:0]
00
00
PAIF 2
0Ah
R11
SAIF_BCLKSEL
[1:0]
SAIF 1
0Bh
Table 15 Master Mode BCLK Control
AUDIO DATA FORMATS
Five popular interface formats are supported:
•
•
•
•
•
Left Justified mode
Right Justified mode
I2S mode
DSP Mode A
DSP Mode B
All five formats send the MSB first and support word lengths of 16, 20, 24 and 32 bits, with the
exception of 32 bit right justified mode, which is not supported.
Audio Data for each stereo channel is time multiplexed with the interface’s Left-Right-Clock (LRCLK),
indicating whether the left or right channel is present. The LRCLK is also used as a timing reference
to indicate the beginning or end of the data words.
In Left Justified, Right Justified and I2S modes, the minimum number of BCLKs per LRCLK period is
2 times the selected word length. LRCLK must be high for a minimum of BCLK periods equivalent to
the audio word length, and low for minimum of the same number of BCLK periods. Any mark to
space ratio on LRCLK is acceptable provided these requirements are met.
In DSP modes A and B, left and right channels must be time multiplexed and input on the input data
line on the Audio Interface. For the PAIF Receiver, all four left/right DAC channels are multiplexed on
DIN1 (assuming DAC_SEL = 00). LRCLK is used as a frame synchronisation signal to identify the
MSB of the first word. The minimum number of BCLKs per LRCLK period is eight times the selected
word length. Any mark to space ratio is acceptable on LRCLK provided the rising edge is correctly
positioned.
LEFT JUSTIFIED MODE
In Left Justified mode, the MSB of the input data is sampled by the WM8581 on the first rising edge
of BCLK following a LRCLK transition. The MSB of the output data changes on the same falling edge
of BCLK as LRCLK and may be sampled on the next rising edge of BCLK. LRCLK is high during the
left samples and low during the right samples.
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Figure 14 Left Justified Mode Timing Diagram
RIGHT JUSTIFIED MODE
In Right Justified mode, the LSB of input data is sampled on the rising edge of BCLK preceding a
LRCLK transition. The LSB of the output data changes on the falling edge of BCLK preceding a
LRCLK transition, and may be sampled on the next rising edge of BCLK. LRCLKs are high during the
left samples and low during the right samples.
Figure 15 Right Justified Mode Timing Diagram
I2S MODE
In I2S mode, the MSB of DIN1/2/3/4 is sampled on the second rising edge of BCLK following a
LRCLK transition. The MSB of the output data changes on the first falling edge of BCLK following an
LRCLK transition, and may be sampled on the next rising edge of BCLK. LRCLKs are low during the
left samples and high during the right samples.
Figure 16 I2S Mode Timing Diagram
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DSP MODE A
In DSP Mode A, the MSB of Channel 1 left data is sampled on the second rising edge of BCLK
following a LRCLK rising edge. Channel 1 right data then follows. For the PAIF Receiver, Channels 2
, 3 and 4 follow as shown in Figure 17.
Figure 17 DSP Mode A Timing Diagram – PAIF Receiver Input Data
For the SAIF receiver, only stereo information is processed.
Figure 18 DSP Mode A Timing Diagram – SAIF Receiver Input Data
The MSB of the left channel of the output data changes on the first falling edge of BCLK following a
low to high LRCLK transition and may be sampled on the rising edge of BCLK. The right channel data
is contiguous with the left channel data.
Figure 19 DSP Mode A Timing Diagram – PAIF/SAIF Transmitter Data
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DSP MODE B
In DSP Mode B, the MSB of Channel 1 left data is sampled on the first BCLK rising edge following a
LRCLK rising edge. Channel 1 right data then follows. For the PAIF Receiver, Channels 2, 3 and 4
follow as shown in Figure 20.
Figure 20 DSP Mode B Timing Diagram – PAIF Receiver Input Data
Figure 21 DSP Mode B Timing Diagram – SAIF Receiver Input Data
The MSB of the output data changes on the same falling edge of BCLK as the low to high LRCLK
transition and may be sampled on the rising edge of BCLK. The right channel data is contiguous with
the left channel data.
Figure 22 DSP Mode B Timing Diagram – PAIF/SAIF Transmitter Data
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AUDIO INTERFACE CONTROL
The register bits controlling the audio interfaces are summarized below. Dynamically changing the
audio data format may cause erroneous operation, and is not recommended.
Interface timing is such that the input data and LRCLK are sampled on the rising edge of the interface
BCLK. Output data changes on the falling edge of the interface BCLK. By setting the appropriate bit
clock polarity control register bits, e.g. PAIFRXBCP, the polarity of BCLK may be reversed, allowing
input data and LRCLK to be sampled on the falling edge of BCLK. Setting the bit clock polarity
register for a transmit interface results in output data changing on the rising edge of BCLK.
Similarly, the polarity of left/right clocks can be reversed by setting the appropriate left right polarity
bits, e.g. PAIFRXLRP.
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
R12
PAIF 3
0Ch
1:0
PAIFRXFMT
[1:0]
10
PAIF Receiver Audio Data Format
Select
11: DSP Format
10: I2S Format
01: Left justified
00: Right justified
3:2
PAIFRXWL
[1:0]
10
PAIF Receiver Audio Data Word
Length
11: 32 bits (see Note 1,2)
10: 24 bits
01: 20 bits
00: 16 bits
4
PAIFRXLRP
0
In LJ/RJ/I2S modes
0 = LRCLK not inverted
1 = LRCLK inverted
In DSP Format:
0 = DSP Mode A
1 = DSP Mode B
5
PAIFRXBCP
0
PAIF Receiver BCLK polarity
0 = BCLK not inverted
1 = BCLK inverted
R13
PAIF 4
0Dh
1:0
PAIFTXFMT
[1:0]
10
PAIF Transmitter Audio Data Format
Select
11: DSP Format
10: I2S Format
01: Left justified
00: Right justified
3:2
PAIFTXWL
[1:0]
10
PAIF Transmitter Audio Data Word
Length
11: 32 bits (see Note 1,2)
10: 24 bits
01: 20 bits
00: 16 bits
4
PAIFTXLRP
0
In LJ/RJ/I2S modes
0 = LRCLK not inverted
1 = LRCLK inverted
In DSP Format:
0 = DSP Mode A
1 = DSP Mode B
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DESCRIPTION
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
5
PAIFTXBCP
0
PAIF Receiver BCLK polarity
0 = BCLK not inverted
1 = BCLK inverted
SAIF Audio Data Format Select
11: DSP Format
R14
SAIF 2
0Eh
1:0
3:2
4
SAIFFMT
[1:0]
10
10
0
10: I2S Format
01: Left justified
00: Right justified
SAIF Audio Data Word Length
11: 32 bits (see Note 1,2)
10: 24 bits
SAIFWL
[1:0]
01: 20 bits
00: 16 bits
SAIFLRP
In LJ/RJ/I2S modes
0 = LRCLK not inverted
1 = LRCLK inverted
In DSP Format:
0 = DSP Mode A
1 = DSP Mode B
5
6
SAIFBCP
SAIF_EN
0
0
SAIF BCLK polarity
0 = BCLK not inverted
1 = BCLK inverted
SAIF Enable
0 = SAIF disabled
1 = SAIF enabled
Table 16 Audio Interface Control
Notes
1. Right Justified mode does not support 32-bit data. If word length xAIFxxWL=11b in Right
Justified mode, the word length is forced to 24 bits.
In all modes, the data is signed 2’s complement. The digital filters internal signal paths process
24-bit data. If the device is programmed to receive 16 or 20 bit data, the device pads the unused
LSBs with zeros. If the device is programmed into 32 bit mode, the 8 LSBs are ignored.
2. In 24 bit I2S mode, any data width of 24 bits or less is supported provided that LRCLK is high for
a minimum of 24 BCLK cycles and low for a minimum of 24 BCLK cycles. If exactly 32 bit clocks
occur in one full left/right clock period the interface will auto detect and configure a 16 bit data
word length.
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DAC FEATURES
DAC INPUT CONTROL
The Primary Audio Interface Receiver has a separate input pin for each stereo DAC. Any input pin
can be routed to any DAC using the DACSEL register bits.
REGISTER ADDRESS
BIT
LABEL
DAC1SEL
[1:0]
DEFAULT
DESCRIPTION
R15
DAC CONTROL 1
0Fh
1:0
00
DAC digital input select
00 = DAC takes data from DIN1
01 = DAC takes data from DIN2
10 = DAC takes data from DIN3
11 = DAC takes data from DIN4
3:2
5:4
7:6
DAC2SEL
[1:0]
01
10
11
DAC3SEL
[1:0]
DAC4SEL
[1:0]
Table 17 DAC Input Select Register
DAC OVERSAMPLING CONTROL
For sampling clock ratios of 256fs to 1152fs the DACs should be programmed to operate at 128
times oversampling rate. For sampling clock ratios of 128fs and 192fs, the DACs must be
programmed to operate at 64 times oversampling rate. The DACOSR register bit selects between
128x and 64x oversampling.
REGISTER ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
DAC Oversampling Rate Control
0= 128x oversampling
R12
PAIF 3
0Ch
6
DACOSR
0
1= 64x oversampling
Table 18 DAC Oversampling Register
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DAC OUTPUT CONTROL
The DAC output control word determines how the left and right inputs to the audio interface are
applied to the left and right DACs:
REGISTER ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
R16
DAC CONTROL 2
10h
3:0
PL[3:0]
1001
PL[3:0]
0000
Left O/P
Right O/P
Mute
Mute
Left
0001
Mute
0010
0011
0100
0101
0110
0111
1000
1001
1010
1011
Right
(L+R)/2
Mute
Mute
Mute
Left
Left
Left
Right
(L+R)/2
Mute
Left
Left
Right
Right
Right
Right
Left
Right
(L+R)/2
1100
1101
Mute
Left
(L+R)/2
(L+R)/2
1110
1111
Right
(L+R)/2
(L+R)/2
(L+R)/2
Table 19 DAC Attenuation Register (PL)
ZERO FLAG OUTPUT
Each DAC channel has a “zero detect circuit” which detects when 1024 consecutive zero samples
have been input. Should both channels of a DAC indicate a zero-detect (or if either DACPD or
DMUTE is set for that DAC), then the Zero Flag for that DAC is asserted. The DZFM register bits
determine which Zero Flag is visible on the MUTE and GPO pins.
REGISTER ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
Selects the source for ZFLAG
000 – All DACs Zero Flag
001 – DAC1 Zero Flag
010 – DAC2 Zero Flag
011 – DAC3 Zero Flag
100 – DAC4 Zero Flag
101 – ZFLAG = 0
R16
DAC CONTROL 2
10h
6:4
DZFM[2:0]
000
110 – ZFLAG = 0
111 – ZFLAG = 0
Table 20 DZFM Register
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INFINITE ZERO DETECT
Setting the IZD register bit will enable the internal Infinite Zero Detect function:
REGISTER ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
R16
DAC CONTROL 2
10h
7
IZD
0
Infinite zero detection circuit control
and automute control
0 = Infinite zero detect automute
disabled
1 = Infinite zero detect automute
enabled
Table 21 IZD Register
With IZD enabled, applying 1024 consecutive zero input samples to a stereo input channel on any
DAC will cause that stereo channel output to be muted. Mute will be removed as soon as either of
those stereo channels receives a non-zero input.
DAC DIGITAL VOLUME CONTROL
The DAC volume may also be adjusted in the digital domain using independent digital attenuation
control registers
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
R20
7:0
LDA1[7:0]
11111111
(0dB)
Digital Attenuation control for DAC1 Left Channel (DACL1) in 0.5dB
steps. See Table 23
DIGITAL
ATTENUATION
DACL 1
8
UPDATE
Not latched
Controls simultaneous update of all Attenuation Latches
0 = Store LDA1 in intermediate latch (no change to output)
1 = Apply LDA1 and update attenuation on all channels
14h
R21
7:0
8
RDA1[6:0]
UPDATE
11111111
(0dB)
Digital Attenuation control for DAC1 Right Channel (DACR1) in
0.5dB steps. See Table 23
DIGITAL
ATTENUATION
DACR 1
Not latched
Controls simultaneous update of all Attenuation Latches
0 = Store RDA1 in intermediate latch (no change to output)
1 = Apply RDA1 and update attenuation on all channels.
15h
R22
7:0
8
LDA2[7:0]
UPDATE
11111111
(0dB)
Digital Attenuation control for DAC2 Left Channel (DACL2) in 0.5dB
steps. See Table 23
DIGITAL
ATTENUATION
DACL 2
Not latched
Controls simultaneous update of all Attenuation Latches
0 = Store LDA2 in intermediate latch (no change to output)
1 = Apply LDA2 and update attenuation on all channels.
16h
R23
7:0
8
RDA2[7:0]
UPDATE
11111111
(0dB)
Digital Attenuation control for DAC2 Right Channel (DACR2) in
0.5dB steps. See Table 23
DIGITAL
ATTENUATION
DACR 2
Not latched
Controls simultaneous update of all Attenuation Latches
0 = Store RDA2 in intermediate latch (no change to output)
1 = Apply RDA2 and update attenuation on all channels.
17h
R24
7:0
8
LDA3[7:0]
UPDATE
11111111
(0dB)
Digital Attenuation control for DAC3 Left Channel (DACL3) in 0.5dB
steps. See Table 23
DIGITAL
ATTENUATION
DACL3
Not latched
Controls simultaneous update of all Attenuation Latches
0 = Store LDA3 in intermediate latch (no change to output)
1 = Apply LDA3 and update attenuation on all channels.
18h
R25
7:0
8
RDA3[7:0]
UPDATE
11111111
(0dB)
Digital Attenuation control for DAC3 Right Channel (DACR3) in
0.5dB steps. See Table 23
DIGITAL
ATTENUATION
DACR3
Not latched
Controls simultaneous update of all Attenuation Latches
0 = Store RDA3 in intermediate latch (no change to output)
1 = Apply RDA3 and update attenuation on all channels.
19h
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REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
R26
7:0
RDA4[7:0]
11111111
(0dB)
Digital Attenuation control for DAC4 Left Channel (DACL4) in 0.5dB
steps. See Table 23.
DIGITAL
ATTENUATION
DACL4
8
UPDATE
Not latched
Controls simultaneous update of all Attenuation Latches
0 = Store LDA4 in intermediate latch (no change to output)
1 = Apply LDA4 and update attenuation on all channels.
1Ah
R27
7:0 MASTDA[7:0]
UPDATE
11111111
(0dB)
Digital Attenuation control for DAC4 Right Channel (DACR4) in
0.5dB steps. See Table 23
DIGITAL
ATTENUATION
DACR4
8
Not latched
Controls simultaneous update of all Attenuation Latches
0 = Store RDA4 in intermediate latch (no change to output)
1 = Apply RDA4 and update attenuation on all channels.
1Bh
R28
7:0 MASTDA[7:0]
11111111
(0dB)
Digital Attenuation control for all DAC channels in 0.5dB steps. See
Table 23
MASTER
DIGITAL
ATTENUATION
8
UPDATE
Not latched
Controls simultaneous update of all Attenuation Latches
0 = Store gain in intermediate latch (no change to output)
1 = Apply gain and update attenuation on all channels.
1Ch
Table 22 Digital Attenuation Registers
Note: The volume update circuit of the WM8581 has two sets of registers; LDAx and RDAx. These
can be accessed individually, or simultaneously by writing to MASTDA – Master Digital
Attenuation. Writing to MASTDA will overwrite the contents of LDAx and RDAx.
L/RDAx[7:0]
ATTENUATION LEVEL
00(hex)
-∞ dB (mute)
01(hex)
-127.5dB
:
:
:
:
:
:
FE(hex)
FF(hex)
-0.5dB
0dB
Table 23 Digital Volume Control Gain Levels
Setting the DACATC register bit causes the left channel attenuation settings to be applied to both left
and right channel DACs from the next audio input sample. No update to the attenuation registers is
required for DACATC to take effect.
REGISTER ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
Attenuator Control
R19
DAC CONTROL 5
13h
6
DACATC
0
0 = All DACs use attenuations as
programmed.
1 = Right channel DACs use
corresponding left DAC
attenuations
Table 24 DAC Attenuation Register
The digital volume control also incorporates a zero cross detect circuit which detects a transition
through the zero point before updating the digital volume control with the new volume. This
mechanism helps prevents pops and clicks during volume transitions, and is enabled by control bit
DZCEN.
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REGISTER ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
R19
DAC CONTROL 5
13h
5
DZCEN
0
DAC Digital Volume Zero Cross
Enable
0 = Zero Cross detect disabled
1 = Zero Cross detect enabled
Table 25 Digital Zero Cross Register
MUTE MODES
The WM8581 has individual mutes for each of the four DAC channels. Setting DMUTE for a channel
will apply a ‘soft-mute’ to the input of the digital filters for that channel. DMUTE[0] mutes DAC1
channel, DMUTE[1] mutes DAC2 channel, DMUTE[2] mutes DAC3 channel and DMUTE[3] mutes
DAC4 channel. Setting the MUTEALL register bit will apply a ‘soft-mute’ to the input of all the DAC
digital filters.
The MUTE pin can also be used to apply soft-mute to the DAC selected by the DZFM register bits.
However, if the MPDENB register bit is set, the MUTE pin will activate a soft-mute for all DACs. The
interaction of the various mute controls is shown in Figure 23.
DMUTE(3:0)
MUTEALL
DACPD(3:0)
PL(3:0)
DZFM (2:0)
DAC_SRC[1:0] = 00
MUTE
(register)
Decode
PCM_N or
AUDIO_N = 1
MPDENB
MUTE
(pin)
DZFM
Selector
Channel 1
Softmute
Channel 2
Softmute
Channel 3
Softmute
zflag1
zflag2
DAC1 i/p
1024
Zeros
Detect
Channel 4
Softmute
3
zflag
DAC2 i/p
DAC3 i/p
DAC4 i/p
zflag4
DAC_SRC[1:0] = 00
UNLOCK = 1
Channel 1
Analogue
Mute
Channel 2
Analogue
Mute
Channel 3
Analogue
Mute
Channel 4
Analogue
Mute
Decode
(register)
IZD
Volume
LDAx/RDAx
(Digital volume)
Figure 23 Mute Circuit Diagram
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DESCRIPTION
REGISTER ADDRESS
BIT
LABEL
DEFAULT
R19
DAC CONTROL 5
13h
3:0
DMUTE[3:0]
0000
DAC channel soft mute
enables:
DMUTE[0] = 1, enable soft-
mute on DAC1.
DMUTE[1] = 1, enable soft-
mute on DAC2.
DMUTE[2] = 1, enable soft-
mute on DAC3.
DMUTE[3] = 1, enable soft-
mute on DAC4.
4
7
MUTEALL
MPDENB
0
0
DAC channel master soft mute.
Mutes all DAC channels:
0 = disable soft-mute on all
DACs.
1 = enable soft-mute on all
DACs.
MUTE pin decode enable:
0 = MUTE activates soft-mute
on DAC selected by DZFM
1 = MUTE activates softmute
on all DACs
Table 26 Mute Registers
1.5
1
0.5
0
-0.5
-1
-1.5
-2
-2.5
0
0.001
0.002
0.003
Time(s)
0.004
0.005
0.006
Figure 24 Application and Release of Mute
Figure 24 shows the application and release of MUTE whilst a full amplitude sinusoid is being played
at 48kHz sampling rate. When MUTE (lower trace) is asserted, the output (upper trace) begins to
decay exponentially from the DC level of the last input sample. The output will decay towards VMID
with a time constant of approximately 64 input samples. If MUTE is applied to all channels for 1024
or more input samples the DAC will be muted if IZD is set. When MUTE is de-asserted, the output
will restart immediately from the current input sample.
All other means of muting the DAC channels will cause a much more abrupt muting of the output.
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DE-EMPHASIS MODE
A digital de-emphasis filter may be applied to each DAC channel. The de-emphasis filter for each
stereo channel is enabled under the control of DEEMP[3:0]. DEEMP[0] enables the de-emphasis
filter for DAC 1, DEEMP[1] enables the de-emphasis filter for DAC 2, DEEMP[2] enables the de-
emphasis filter for DAC 3 and DEEMP[3] enables the de-emphasis filter for DAC 4.
REGISTER ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
R17
DAC CONTROL 3
11h
3:0
DEEMP[3:0]
0000
De-emphasis mode select:
DEEMP[0] = 1, enable De-
emphasis on DAC1.
DEEMP[1] = 1, enable De-
emphasis on DAC2.
DEEMP[2] = 1, enable De-
emphasis on DAC3.
DEEMP[3] = 1, enable De-
emphasis on DAC4.
4
DEEMPALL
0
0 = De-emphasis controlled by
DEEMP[3:0]
1 = De-emphasis enabled on all
DACs
Table 27 De-emphasis Register
Refer to, Figure 41, Figure 42, Figure 43 and Figure 44 for details of the De-Emphasis modes at
different sample rates.
DAC OUTPUT PHASE
The DAC Phase control word determines whether the output of each DAC is non-inverted or inverted
REGISTER ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
Controls phase of DAC outputs
0 = inverted
R18
DAC CONTROL 4
12h
7:0
PHASE
[7:0]
11111111
1 = non-inverted
PHASE[0] = 0 inverts phase of
DAC1L output
PHASE[1] = 0 inverts phase of
DAC1R output
PHASE[2] = 0 inverts phase of
DAC2L output
PHASE[3] = 0 inverts phase of
DAC2R output
PHASE[4] = 0 inverts phase of
DAC3L output
PHASE[5] = 0 inverts phase of
DAC3R output
PHASE[6] = 0 inverts phase of
DAC4L output
PHASE[7] = 0 inverts phase of
DAC4R output
Table 28 DAC Output Phase Register
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ADC FEATURES
ADC HIGH-PASS FILTER DISABLE
The ADC digital filters incorporate a digital high-pass filter. By default, this is enabled but can be
disabled by setting the ADCHPD register bit to 1. This allows the input to the ADC to be DC coupled.
REGISTER ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
ADC high-pass filter disable
0 = high-pass filter enabled
1 = high-pass filter disabled
R29
ADC CONTROL 1
1Dh
4
ADCHPD
0
Table 29 ADC Functions Register
ADC OVERSAMPLING RATE SELECT
The internal ADC signal processing operates at an oversampling rate of 128fs for all MCLK:LRCLK
ratios. The exception to this is for operation with a 128fs or 192fs master clock, where the internal
oversampling rate of the ADC is 64fs.
For ADC operation at 96kHz in 256fs or 384fs mode it is recommended that the user set the
ADCOSR bit. This changes the ADC signal processing oversampling rate from 128fs to 64fs.
Similarly, for ADC operation at 192kHz in 128fs or 192fs mode it is recommended that the user set
the ADCOSR bit to change the oversampling rate from 64fs to 32fs.
REGISTER ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
ADC oversample rate select
0 = 128/64x oversampling
1 = 64/32x oversampling
R29
ADC CONTROL 1
1Dh
3
ADCOSR
0
Table 30 ADC Functions Register
ADC MUTE
As with the DAC, each ADC channel also has a mute control bit, which mutes the inputs to the ADC.
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
R29
ADC CONTROL 1
1Dh
0
AMUTEL
0
ADC Mute select
0 : Normal Operation
1: mute ADC left
1
2
AMUTER
0
0
ADC Mute select
0 : Normal Operation
1: mute ADC right
AMUTEALL
ADC Mute select
0 : Normal Operation
1: mute both ADC channels
Table 31 ADC Mute Register
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DIGITAL ROUTING OPTIONS
The WM8581 has extremely flexible digital interface routing options, which are illustrated in Figure 25.
It has a S/PDIF Receiver, S/PDIF Transmitter, four Stereo DACs, a Stereo ADC, a Primary Audio
Interface and a Secondary Audio Interface.
Each DAC has its own digital input pin DIN1/2/3/4. Internal multiplexers in the Primary Audio Interface
Receiver allow the data received on any DIN pin to be routed to any DAC. Any DIN pin routed to
DAC1 can also be routed to the S/PDIF transmitter and Secondary Audio Interface Transmitter.
DAC1 may also be used to convert received S/PDIF data, or data received from the Secondary Audio
Interface. DACs 2-4 take data only from the Primary Audio Interface. The Audio Interfaces can also
output ADC data or received S/PDIF data.
The S/PDIF transmitter can output S/PDIF received data, ADC data, or data from either Audio
Interface.
Figure 25 Digital Routing
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The registers described below configure the digital routing options.
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
R12
8:7
DAC_SRC
[1:0]
11
DAC1 Source:
00 = S/PDIF received data.
10 = SAIF Rx data
11 = PAIF Rx data
Note: When DAC_SRC = 00,
DAC2/3/4 may be turned off,
depending on RX2DAC_MODE.
R13
R14
R30
8:7
8:7
1:0
PAIFTX_SRC
[1:0]
01
00
00
Primary Audio Interface Tx Source:
00 = S/PDIF received data.
01 = ADC digital output data.
10 = SAIF Rx data
SAIFTX_SRC
[1:0]
Secondary Audio Interface Tx Source:
00 = S/PDIF received data.
01 = ADC digital output data.
11 = PAIF Rx data
TXSRC
[1:0]
S/PDIF Transmitter Data Source.
00 = S/PDIF received data(‘thru-
path’)
01 = ADC digital output data.
10 = SAIF Rx data
11 = PAIF Rx data
3
REAL_THRU
0
S/PDIF Thru Mode Control
0 = SPDIFOP pin sources output
of S/PDIF Tx
1 = SPDIFOP pins sources output
of S/PDIF IN Mux
Table 32 Interface Source Select Registers
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CLOCK SELECTION
To accompany the flexible digital routing options, the WM8581 offers a clock configuration scheme
for each interface. By default, the user can choose the interface clock from MCLK, ADCMCLK,
PLLACLK or PLLBCLK, with some restrictions which are autoconfigured. For example, if the S/PDIF
receiver is routed to the DAC, appropriate interface clocks are autoconfigured. These are described
in the following sections.
For some interfaces, the rate can be controlled either by external LRCLK (slave mode), internal
LRCLK (master mode) or by control register. The available options are described below.
It is possible to override the autoconfiguration (setting CLKSEL_MAN = bit 6 of Register 8 to a 1),
allowing the user to manually select any available clock for any interface using the appropriate
CLKSEL register bits.
DAC INTERFACE
The DAC_CLKSEL register selects the DAC clock source from MCLK, PLLACLK or PLLBCLK. If the
digital routing has been set such that the DAC1 is sourcing the S/PDIF Receiver, then PLLACLK is
automatically selected, and DACs 2/3/4 are powered down by default.
With RX2DAC_MODE set, DAC1 sources the S/PDIF receiver and DACs 2,3 and 4 source the PAIF
(and hence are not powered down). The PAIFRX_LRCLK determines the sampling rate, so the
S/PDIF sampling rate must be synchronised with PAIF_LRCLK. Also, use of the S/PDIF receiver
means that PLLACLK and PLLBCLK are not available, and the MCLK applied to the DACs must be
at a standard audio rate.
The rate at which the DACs operate is determined by the DAC Rate module, divided down from the
MCLK signal. It calculates the rate based on the digital routing setup, and selects between
128/192/256/384/512/768/1152fs. When sourcing from the PAIF Receiver, PAIFRX_LRCLK (internal
or external) is used in the rate calculation. When sourcing from the SAIF Receiver, SAIF_LRCLK
(internal or external) is used in the rate calculation. When DAC1 is sourcing directly from the S/PDIF
receiver, the sub-frame clock, SFRM_CLK, is used in the rate calculation. However this can be
changed by setting the RX2DAC_MODE register bit, allowing the PAIF_LRCLK to determine the
sampling rate.
Figure 26 DAC Clock Selection
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
DAC clock source
R8
1:0
DAC_CLKSEL
00
00 = MCLK pin
01 = PLLACLK
10 = PLLBCLK
11 = MCLK pin
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DAC Rate and Power down control
R15
8
RX2DAC_MODE
0
(only valid when DAC_SRC = 00)
0 = SFRM_CLK determines rate,
DACs 2/3/4 powered down
1 = PAIFRX_LRCLK determines
rate, DACs 2/3/4 source PAIFRX
Table 33 DAC Clock Control
ADC INTERFACE
The ADC_CLKSEL register selects the ADC clock source from ADCMCLK, PLLACLK, PLLBCLK, or
ADCMCLK. However, if the S/PDIF receiver is powered up, the PLLACLK and PLLBCLK are invalid
for ADC operation, so the choice is limited to ADCMCLK (default) or MCLK. The rate that the ADC
operates at is determined by the ADC Rate module. It calculates the rate based on the digital routing
setup. If the ADC is sourced by the PAIF Transmitter, PAIFTX_LRCLK is used in the rate calculation.
If the ADC is sourced by the SAIF Transmitter (and PAIF Transmitter has another source),
SAIF_LRCLK is used in the rate calculation. If the S/PDIF Transmitter (only) is sourcing the ADC,
then the rate is set by the ADC_RATE register bits.
The ADC clock source can be independent from the DACs and PLLs, however for optimum
performance, it is recommended that where possible, clock sources on the WM8581 are
synchronous. Performance may be degraded if this condition is not met.
Figure 27 ADC Clock Selection
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
ADC clock source
R8
3:2
ADC_CLKSEL
00
00 = ADCMLCK pin
01 = PLLACLK
10 = PLLBCLK
11 = MCLK pin
R29
7:5
ADCRATE[2:0]
010
ADC Rate Control (only used when
the S/PDIF Tx is the only interface
sourcing the ADC)
000 = 128fs
001 = 192fs
010 = 256fs
011 = 384fs
100 = 512fs
101 = 768fs
110 = 1152fs
Table 34 ADC Clock Control
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S/PDIF INTERFACES
The TX_CLKSEL register selects the clock for the S/PDIF Transmitter from ADCMCLK, PLLACLK,
PLLBCLK, or MCLK. The S/PDIF Receiver only uses PLLACLK. If the digital routing has been
configured such that the S/PDIF Transmitter is sourcing the S/PDIF Receiver, then PLLACLK is
automatically selected. The rate that the S/PDIF Transmitter operates at is determined by the S/PDIF
Tx Rate module. It calculates the rate based on the digital routing setup. When sourcing from the
S/PDIF Receiver, the SFRM_CLK is used in the rate calculation. When sourcing from the PAIF
Receiver, PAIFRX_LRCLK is used in the rate calculation. When sourcing from the SAIF Receiver,
SAIFRX_LRCLK is used in the rate calculation. When sourcing the ADC, the rate is determined by
either the PAIFTX_LRCLK (if the PAIF Tx also sources the ADC) or the ADC_RATE register.
Figure 28 S/PDIF Clock Selection
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
R8
5:4
TX_CLKSEL
01
S/PDIF TX clock source
00 = ADCMLCK pin
01 = PLLACLK
10 = PLLBCLK
11 = MCLK pin
Table 35 S/PDIF Transmitter Clock Control
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PRIMARY AUDIO INTERFACE RECEIVER (PAIF RX)
The PAIF Receiver requires a left-right-clock (LRCLK) and a bit-clock (BCLK). These can be supplied
externally (slave mode) or they can be generated internally by the WM8581 (master mode). The
master mode LRCLK/BCLK are created by the Master Mode Clock Gen module. The control of this
module is described on page 34. The clock supplied to this module is selected by the
PAIFRXMS_CLKSEL register and can be MCLK, PLLACLK, or PLLBCLK.
Figure 29 PAIF Receiver Clock Selection
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
R9
7:6
PAIFRXMS_
CLKSEL
00
PAIFRX Master Mode clock source
00 = MCLK pin
01 = PLLACLK
10 = PLLBCLK
11 = MCLK pin
Table 36 PAIF Receiver Master Mode Clock Control
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WM8581
PRIMARY AUDIO INTERFACE TRANSMITTER (PAIF TX)
The PAIF Transmitter requires a left-right-clock (LRCLK) and a bit-clock (BCLK). These can be
supplied externally (slave mode) or they can be generated internally by the WM8581 (master mode).
The master mode LRCLK/BCLK are created by the Master Mode Clock Gen module. The control of
this module is described on page 34. The clock supplied to this module can be ADCMCLK,
PLLACLK, PLLBCLK, or MCLK and is selected by the internal signal paiftxms_clksel’. If the PAIF
Transmitter is sourcing the S/PDIF Receiver, it is recommended that the interface operate in master
mode. For this path, paiftxms_clksel selects PLLACLK. For all other digital routing options,
paiftxms_clksel automatically selects whichever clock the adc_clk is using.
If in slave mode, and adc_clk is set to be MCLK, then the PAIFRX_BCLK is used as the BCLK for
the PAIF Transmitter.
Figure 30 PAIF Transmitter Clock Selection
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SECONDARY AUDIO INTERFACES (SAIF RX AND SAIF TX)
The Transmit and Receive sides of the Secondary Audio Interface share a common LRCLK and a
common BCLK. These can be supplied externally (slave mode) or they can be generated internally
by the WM8581 (master mode). The master mode LRCLK/BCLK are created by the Master Mode
Clock Gen module. The control of this module is described on page 34. The clock supplied to this
module can be ADCMCLK, PLLACLK, PLLBCLK, or MCLK and is selected using the
SAIFMS_CLKSEL register. If the digital routing has been configured such that the SAIF Transmitter
is sourcing the S/PDIF Receiver, then PLLACLK is automatically selected, and it is recommended
that the interface operate in master mode. However, if the SAIF Transmitter sources something other
than the S/PDIF Receiver, and the S/PDIF Receiver is powered up, the PLLACLK and PLLBCLK are
invalid for SAIF operation, so the choice is limited to ADCMCLK (default) or MCLK.
Figure 31 SAIF Clock Selection
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
R11
7:6
SAIFMS_
CLKSEL
11
SAIF Master Mode clock source
00 = ADCMCLK pin
01 = PLLACLK
10 = PLLBCLK
11 = MCLK pin
Table 37 SAIF Master Mode Clock Control
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MANUAL CLOCK SELECTION
It is possible to override all default clocking configuration restrictions by setting CLKSEL_MAN. When
CLKSEL_MAN is set, default clocking configurations such as automatic selection of PLLACLK for
DAC1 when DACSRC=00 (S/PDIF received data) are not applied. Instead, clock selection is
determined only by the relevant CLK_SEL register.
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
R8
CLKSEL
08h
6
CLKSEL_MAN
0
Clock selection auto-configuration
override
0 = auto-configuration enabled,
clock configuration follows
restrictions described in page 43
to page 48.
1 = auto-configuration disabled,
clock configuration follows
relevant CLKSEL bits in R8 to
R11.
Table 38 Manual Clock Selection
PHASE-LOCKED LOOPS AND S/PDIF CLOCKING (SOFTWARE MODE)
The WM8581 is equipped with two independent phase-locked loop clock generators and a
comprehensive clocking scheme which provides maximum flexibility and function and many
configurable routing possibilities for the user in software mode. An overview of the software mode
clocking scheme is shown in Figure 32.
Figure 32 PLL and Clock Select Circuit
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OSCILLATOR
The function of the oscillator is to generate the OSCCLK oscillator clock signal. This signal may be
used as:
•
•
•
The clock source for the PLLs.
A selectable clock source for the MCLK pin, when the pin is configured as an output.
A selectable clock source for the CLKOUT pin, when enabled.
Whenever the PLLs or the S/PDIF receiver is enabled, the OSCCLK signal must be present to
enable the PLLs to generate the necessary clock signals.
The oscillator uses a Pierce type oscillator drive circuit. This circuit requires an external crystal and
appropriate external loading capacitors. The oscillator circuit contains a bias generator within the
WM8581 and hence an external bias resistor is not required. Crystal frequencies between 10 and
14.4MHz or 16.28MHz and 27MHz can be used in software mode. In this case the oscillator XOUT
must be powered up using the OSCPD bit. The recommended circuit is shown in the recommended
components diagram, please refer to Figure 49.
Alternatively, an external CMOS compatible clock signal can be applied to the XIN pin in the absence
of a crystal. This is not recommended when using the PLL as the PLL requires a jitter-free OSCCLK
signal for optimum performance. In this case the oscillator XOUT can be powered down using the
OSCPD bit.
The oscillator XOUT pin has one control bit as shown in Table 39.
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
R51
PWRDN 2
33h
0
OSCPD
0
Oscillator XOUT Power Down
0 = Power Up XOUT (crystal mode)
1 = Power Down XOUT (CMOS
clock input mode)
Table 39 Oscillator Control
PHASE-LOCKED LOOP (PLL)
The WM8581 has two on-chip phase-locked loop (PLL) circuits which can be used to synthesise two
independent clock signals (PLLACLK and PLLBCLK) from the external oscillator clock. The PLLs can
be used to:
•
Generate clocks necessary for the S/PDIF receiver to lock on to and recover S/PDIF data from an
incoming S/PDIF data stream.
•
•
Generate clocks which may be used to drive the MCLK and/or CLKOUT pins.
Generate clocks which may be used by the S/PDIF transmitter to encode and transmit a S/PDIF
data stream.
•
•
Generate clocks which may be used as the master clock source for the the ADC and DACs.
Generate clocks which may be used by the master mode clock generator to generate the BCLK
and LRCLK signals for the digital audio interfaces.
The PLLs can be enabled or disabled using the register bits shown in Table 40.
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
R51
PWRDN 2
33h
1
2
PLLAPD
PLLBPD
1
1
PLL Power Down Control
0 = Power Up PLL
1 = Power Down PLL
Table 40 PLL Power Down Control
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The PLLs have two modes of operation:
PLL S/PDIF Receive Mode (Selected if S/PDIF Receiver Enabled)
•
In S/PDIF receive mode, PLLA is automatically controlled by the S/PDIF receiver to allow the
receiver to use PLLA to track and lock on to the incoming S/PDIF data stream. In this case, CLK1 is
automatically maintained at a constant frequency of 256fs relative to the sample rate of the
recovered S/PDIF stream. PLLB must be configured to produce CLK2, a specific reference clock for
the S/PDIF receiver.
PLLACLK may be used as a 256fs or 128fs (selectable – refer to Table 45) master clock source
when in S/PDIF receiver mode. PLLBCLK is not available and must not be selected as the clock
source for any internal function when the S/PDIF receiver is enabled.
If the sample frequency of the incoming stream is changed and PLLA is forced to unlock in order to
track to the new sample frequency, the PLLACLK signal will be stopped until the S/PDIF receiver
has locked to the incoming stream at the new sample frequency. If the incoming S/PDIF stream
stops, the PLLA_ N and PLLA_K values will be frozen and the PLLACLK will continue at the
frequency set by the last recovered S/PDIF stream.
Refer to Table 41 and Table 43 for details of the registers available for configuration in this mode.
Refer to the S/PDIF Receive Mode Clocking section on page 56 for full details.
•
PLL User Mode (Selected if S/PDIF Receiver Disabled)
In user mode, the user has full control over the function and operation of both PLLA and PLLB. In
this mode, the user can accurately specify the PLL N and K multiplier values and the pre and post-
scale divider values and can hence fully control the generated clock frequencies.
Refer to Table 41 and Table 43 for details of the registers available for configuration in this mode.
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
R0
PLLA 1/
DEVID1
00h
8:0
PLLA_K[8:0]
100100001
Fractional (K) part of PLLA
frequency ratio (R) I.
Value K is one 22-digit binary
number spread over registers R0,
R1 and R2 as shown.
R1
8:0
3:0
PLLA_K[17:9]
PLLA_K[21:18]
101111110
1101
PLLA 2/
DEVID2
01h
Reading from these registers will
return the device ID.
R0 returns 10000001 = 81h
R1 returns 10000101 = 85h
R2
PLLA 3/
DEVREV
02h
Device ID readback is not possible
in continuous readback mode
(CONTREAD=1).
7:4
PLLA_N[3:0]
0111
Integer (N) part of PLLA frequency
ratio(R)II.
Use values in the range 5 ≤ PLLA_N
≤ 13 as close as possible to 8.
Reading from this register will return
the device revision number.
R4
PLLB 1
04h
8:0
8:0
3:0
PLLB_K[8:0]
PLLB_K[17:9]
PLLB_K[21:18]
100100001
101111110
1101
Fractional (K) part of PLLB
frequency ratioII(R).
Value K is one 22-digit binary
number spread over registers R4,
R5 and R6 as shown.
R5
PLLB 2
05h
Note: PLLB_K must be set to
specific values when the S/PDIF
receiver is used. Refer to S/PDIF
Receive Mode Clocking section
for details.
R6
PLLB 3
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DESCRIPTION
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
06h
7:4
PLL_N[3:0]
0111
Integer (N) part of PLLB frequency
ratio (R).
Use values in the range 5 ≤ PLLB_N
≤ 13 as close as possible to 8
Note: PLLB_N must be set to
specific values when the S/PDIF
receiver is used. Refer to S/PDIF
Receive Mode Clocking section
for details.
Table 41 User Mode PLL_K and PLL_N Multiplier Control
Parameter
PRESCALE_A
PRESCALE_B
PLLA_N
PLL User Mode
Manual
PLL S/PDIF Receiver Mode
Write PRESCALE_B Value
Configure Specified PLLB Frequency
Automatically Controlled
Automatically Controlled
Configure Specified PLLB Frequency
Configure Specified PLLB Frequency
Automatically Controlled
Not Used
Manual
Manual
PLLA_K
Manual
PLLB_N
Manual
PLLB_K
Manual
FREQMODE_A
FREQMODE_B
POSTSCALE_A
POSTSCALE_B
Manual
Manual
Manual
256fs/128fs PLLACLK Select
Not Used
Manual
Table 42 PLL Control Register Function in PLL User and PLL S/PDIF Receiver Modes
PLL CONFIGURATION
The PLLs perform a configurable frequency multiplication of the input clock signal (f1). The
multiplication factor of the PLL (denoted by ‘R’) is variable and is defined by the relationship: R = (f2 ÷
f1).
The multiplication factor for each PLL is set using register bits PLLx_N and PLLx_K (refer to Table 41). The
multiplication effect of both the N and K multipliers are additive (i.e. if N is configured to provide a
multiplication factor of 8 and K is configured to provide a multiplication factor of 0.192, the overall
multiplication factor is 8 + 0.192 = 8.192).
In order to choose and configure the correct values for PLLx_N and PLLx_K, multiplication factor R
must first be calculated. Once value R is calculated, the value of PLLx_N is the integer (whole
number) value of R, ignoring all digits to the right of the decimal point. For example, if R is calculated
to be 8.196523, PLL_N is simply 8.
Once PLLx_N is calculated, the PLLx_K value is simply the integer value of (222 (R-PLLx_N)). For
example, if R is 8.196523 and PLLx_N is 8, PLLx_K is therefore (222 (8.196523-8)), which is 824277
(ignoring all digits to the right of the decimal point).
Note: the PLLs are designed to operate with best performance (shortest lock time and optimum
stability) when f2 is between 90 and 100MHz and PLLx_N is 8. However, acceptable PLLx_N values
lie in the range 5 ≤ PLLx_N ≤ 13.
Each PLL has an output divider to allow the f2 clock signal to be divided to a frequency suitable for
use as the source for the MCLK and CLKOUT outputs, the S/PDIF transmitter and the internal ADC
and DACs. The divider output is configurable and is set by the FREQMODE_A or FREQMODE_B
bits in conjunction with the POSTSCALE_A and POSTSCALE_B bits. Each PLL is also equipped
with a pre-scale divider which offers frequency divide by one or two before the OSCCLK signal is
input into the PLL. Please refer to Table 43 for details.
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REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
R3
PLLA 4
03h
0
PRESCALE_A
0
PLL Pre-scale Divider Select
0 = Divide by 1 (PLL input clock =
oscillator clock)
1 = Divide by 2 (PLL input clock =
oscillator clock ÷ 2)
R7
0
PRESCALE_B
0
PLLB 4
07h
Note: PRESCALE_A must be
set to the same value as
PRESCALE_B in PLL S/PDIF
receiver mode.
R3
PLLA 4
03h
4:3
4:3
FREQMODE_A
[1:0]
10
10
PLL Output Divider Select
PLL S/PDIF Receiver Mode
FREQMODE_A is automatically
controlled. FREQMODE_B is not
used.
R7
FREQMODE_B
[1:0]
PLLB 4
07h
PLL User Mode
Used in conjunction with the
POSTSCALE_x bits. Refer to Table
44.
R3
PLLA 4
03h
1
1
POSTSCALE_A
POSTSCALE_B
0
0
PLL Post-scale Divider Select
PLL S/PDIF Receiver Mode
POSTSCALE_A is used to configure
a 256fs or 128fs PLLACLK,
POSTSCALE_B is not used. Refer
to Table 45.
R7
PLLB 4
07h
PLL User Mode
Used in conjunction with the
FREQMODE_x bits. Refer to Table
44.
Table 43 Pre and Post PLL Clock Divider Control
FREQMODE_x[1:0]
f2 TO PLLxCLK DIVISION FACTOR
POSTSCALE_x
0
÷2
÷4
÷8
÷12
1
00
01
10
11
÷4
÷8
÷16
÷24
Table 44 PLL User Mode Clock Divider Configuration
POSTSCALE_A
PLLACLK FREQUENCY
0
1
256fs
128fs
Table 45 PLL S/PDIF Receiver Mode Clock Divider Configuration
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PLL CONFIGURATION EXAMPLE
Consider the situation where the oscillator clock (OSCCLK) input frequency is fixed at 12MHz and the
required PLLBCLK frequency is 12.288MHz.
1. Calculate the f2, FREQMODE_B and POSTSCALE_B Values
The PLL is designed to operate with best performance when the f2 clock is between 90 and 100MHz. The
necessary PLLBCLK frequency is 12.288MHz. Choose POSTSCALE_B and FREQMODE_B values to set
the f2 frequency in the range of 90 to 100MHz. In this case, the default values (POSTSCALE_B = 0 and
FREQMODE_B[1:0] = 10) will configure the f2 to PLLBCLK divider as 8 and hence will set the f2 frequency at
98.304MHz; this value is within the 90 to 100MHz range and is hence acceptable.
•
•
•
POSTSCALE_B = 0
FREQMODE_B [1:0] = 10b
f2 = 98.304MHz
2. Calculate R Value
Using the relationship: R = (f2 ÷ f1), the value of R can be calculated.
•
•
•
R = (f2 ÷ f1)
R = (98.304 ÷ 12)
R = 8.192
3. Calculate PLLB_N Value
The value of PLLB_N is the integer (whole number) value of R, ignoring all digits to the right of the
decimal point. In this case, R is 8.192, hence PLLB_N is 8.
4. Calculate PLL_K Value
The PLLB_K value is simply the integer value of (222 (R-PLLB_N)).
•
•
•
PLLB_K = integer part of (222 x (8.192 – 8))
PLLB_K = integer part of 805306.368
PLLB_K = 805306 (decimal) / C49BA (hex)
A number of example configurations are shown in Table 46. Many other configurations are possible; Table 46
shows only a small number of valid possibilities. As both PLLs are identical, the same configuration
procedure applies for both.
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OSC
PRE-
SCALE
_x
F1
F2
R
PLLx_N
PLLx_K
FREQ
MODE_x
[1:0]
POST-
SCALE_x
PLLxCLK
CLK
(MHz)
(MHz)
(Hex)
(Hex)
(MHz)
(MHz)
12
12
12
12
12
12
12
24
24
24
24
24
24
24
27
27
27
27
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
1
1
1
12
12
98.304
98.304
98.304
98.304
98.304
98.304
98.304
8.192
8.192
8.192
8.192
8.192
8.192
8.192
8
8
8
8
8
8
8
7
7
7
7
7
7
7
7
7
6
6
C49BA
C49BA
C49BA
C49BA
C49BA
C49BA
C49BA
21B089
21B089
21B089
21B089
21B089
21B089
21B089
1208A5
1208A5
2C2B24
2C2B24
00
01
01
10
10
11
11
00
01
01
10
10
11
11
00
01
00
01
1
0
1
0
1
0
1
1
0
1
0
1
0
1
1
1
1
1
24.576
24.576
12.288
12.288
6.144
12
12
12
12
8.192
12
4.096
12
90.3168 7.5264
90.3168 7.5264
90.3168 7.5264
90.3168 7.5264
90.3168 7.5264
90.3168 7.5264
90.3168 7.5264
22.5792
22.5792
11.2896
11.2896
5.6448
7.5264
3.7632
24.576
12.288
22.5792
11.2896
12
12
12
12
12
12
13.5
13.5
13.5
13.5
98.304
98.304
7.2818
7.2818
90.3168 6.6901
90.3168
6.6901
Table 46 User Mode PLL Configuration Examples
When considering settings not shown in this table, the key configuration parameters which must be selected
for optimum operation are:
•
•
•
90MHz ≤ f2 ≤ 100MHz
5 ≤ PLLx_N ≤ 13
OSCCLOCK = 10 to 14.4MHz or 16.28 to 27MHz
CLOCK OUTPUT (CLKOUT) AND MCLK OUTPUT (MCLK)
The clock output (CLKOUT) pin can be used as a clock output. This pin is intended to be used as a
clock source pin for providing the central clock reference for an audio system.
The CLKOUT clock source can be selected from OSCCLK, PLLACLK or PLLBCLK. The control bits
for the CLKOUT signal are shown in Table 47.
The MCLK pin can be configured as an input or output – the WM8581 should be powered down when
switching MCLK between an input and an output. As an output, MCLK can be sourced from
OSCCLK, PLLACLK or PLLBCLK.
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
R7
PLLB 4
07h
6:5
MCLKOUTSRC
00
MCLK pin output source
00 = Input – Source MCLK pin
01 = Output – Source PLLACLK
10 = Output – Source PLLBCLK
11 = Output – Source OSCCLK
CLKOUT pin source
8:7
CLKOUTSRC
11
00 = No Output (tristate)
01 = Output – Source PLLACLK
10 = Output – Source PLLBCLK
11 = Output – Source OSCCLK
Table 47 MCLK and CLKOUT Control
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S/PDIF RECEIVE MODE CLOCKING
In S/PDIF receive mode, the PLLA_N and PLLA_K values are automatically controlled by the
S/PDIF receiver to allow the receiver to use PLLA to lock on to and track the incoming S/PDIF data
stream. PLLB must be configured to produce a specific reference clock frequency for the S/PDIF
receiver.
The S/PDIF receiver has three clocking modes based on the incoming S/PDIF stream sample rate.
The modes are:
•
•
•
Mode 1: Incoming S/PDIF Sample Rate = 88.2kHz -1% to 96kHz +1%
Mode 2: Incoming S/PDIF Sample Rate = 44.1kHz -1% to 48kHz +1%
Mode 3: Incoming S/PDIF Sample Rate = 32kHz +/- 1%
Before the S/PDIF receiver is enabled, it is important that the PLLB_N and PLLB_K register values
(and the PRESCALE_x values as appropriate) are manually configured in a specific default state.
Note that the PRESCALE_A value must always be set to the same value as PRESCALE_B.
The specified PLLB f2 frequencies that must be configured using the PLLB_N and PLLB_K register
values (and the PRESCALE_x values as appropriate) for reception of specific S/PDIF sample rates
are as follows:
•
Modes 1/2/3 (32/44.1/48/88.2/96kHz Sample Rates): PLLB f2 = 94.3104MHz
The FREQMODE_B[1:0] bits and POSTSCALE_B bit are not used in PLL S/PDIF receiver mode.
The PLL register settings are configured by default to allow S/PDIF receiver operation using a 12MHz
crystal clock. The appropriate PLLB register values must be updated if any crystal clock frequency
other than 12MHz is used.
Refer to Table 48 for details of a number of recommended PLLB configurations. Many other
configurations are possible; please refer to PLL Configuration section for details regarding how to
calculate alternative settings.
OSC
CLK
(MHz)
11.2896
12
PRE-
SCALE_X
S/PDIF RECEIVER
SAMPLE RATE(S) (kHz)
F1
F2
R
PLLB_N PLLB_K
COMMENT
(MHz)
(MHz)
(Hex)
(Hex)
0
0
0
1
1
1
32 / 44.1 / 48 / 88.2 / 96 11.2896 94.3104 8.3537
8
7
7
9
7
6
16A3B3
36FD21
2B3333
Set N, K
Default Setting
Set K
32 / 44.1 / 48 / 88.2 / 96
32 / 44.1 / 48 / 88.2 / 96
32 / 44.1 / 48 / 88.2 / 96
32 / 44.1 / 48 / 88.2 / 96
32 / 44.1 / 48 / 88.2 / 96
12
94.3104 7.8592
12.288
19.2
12.288 94.3104 7.675
9.6
12
94.3104 9.824
94.3104 7.8592
94.3104 6.986
346C6A Set Prescales, N, K
36FD21 Set Prescales
3F19E5 Set Prescales, N, K
24
27
13.5
Table 48 S/PDIF Receive Mode PLLB Initial Configuration Examples
The recommended configuration sequences are as follows:
TO INITIALLY CONFIGURE THE SYSTEM FOR S/PDIF RECEIVER STARTUP:
1. Write appropriate calculated values (relative to oscillator frequency) to
PRESCALE_A, PRESCALE_B, PLLB_N and PLLB_K.
2. Enable PLLA and PLLB by clearing the PLLAPD and PLLBPD bits.
3. Enable S/PDIF receiver by clearing the SPDIFRXPD and SPDIFPD bits.
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PHASE-LOCKED LOOPS AND S/PDIF CLOCKING (HARDWARE MODE)
In hardware mode, the user has no access to the internal clocking control registers and hence a
default configuration is loaded at reset to provide maximum functionality.
The S/PDIF receiver is enabled and hence the PLLs operate in S/PDIF receiver mode and all PLL
and S/PDIF receiver control is fully automatic. All supported S/PDIF receiver sample rates can be
used.
FREQMODE_x and POSTSCALE_x control is fully automatic to ensure that the MCLK output is
maintained at 256fs relative to the S/PDIF received sample rate.
In hardware mode, the OSCCLK must be 12MHz and hence the external crystal (or applied XIN
clock) must be 12MHz. No other OSCCLK frequencies are supported in hardware mode.
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S/PDIF TRANSCEIVER
FEATURES
•
•
•
•
•
•
•
•
IEC-60958-3 compatible with 32k frames/s to 96k frames/s support
Support for Reception and Transmission of S/PDIF data
Clock synthesis PLL with reference clock input and ultra-low jitter output
Input mux with support for up to four S/PDIF inputs
Register controlled Channel Status recovery and transmission
Register read-back of recovered Channel Status bits and error flags
Detection of non-audio data, sample rate, and pre-emphasised data
Programmable GPO for error flags, frame status flags and clocks
An IEC-60958-3 compatible S/PDIF transceiver is integrated into the WM8581. Operation of the
S/PDIF function may be synchronous or asynchronous to the rest of the digital audio circuits.
The receiver performs data and clock recovery, and sends recovered data either to an external
device such as a DSP (via the Digital Audio Interfaces), or if the data is audio PCM, it can route the
stereo recovered data to DAC1. The recovered clock may be routed out of the WM8581 onto a pin
for external use, and may be used to clock the internal DAC as required.
The transmitter generates S/PDIF frames where audio data may be sourced from the ADC, S/PDIF
Receiver, or the Digital Audio Interfaces.
S/PDIF FORMAT
S/PDIF is a serial, bi-phase-mark encoded data stream. An S/PDIF frame consists of two sub-
frames. Each sub-frame is made up of:
•
Preamble – a synchronization pattern used to identify the start of a 192-frame block or sub-
frame
•
•
•
•
•
•
4-bit Auxiliary Data (AUX) – ordered LSB to MSB
20-bit Audio Data (24-bit when combined with AUX) – ordered LSB to MSB
Validity Bit – a 1 indicates invalid data in that sub-frame
User Bit – over 192-frames, this forms a User Data Block,
Channel Bit – over 192-frames, this forms a Channel Status Block
Parity Bit – used to maintain even parity over the sub-frame (except the preamble)
An S/PDIF Block consists of 192 frames. Channel and User blocks are incorporated within the 192-
frame S/PDIF Block. For Consumer mode only the first 40-frames are used to make up the Channel
and User blocks. Figure 33 illustrates the S/PDIF format.
Frame
192
Frame
1
. . . . . . . . .
Subframe 1
Subframe 2
0
3 4
7 8
27 28
31
32 bit
Word
Sync
preamble
Aux
Audio Sample Word
V
U
C
P
Figure 33 S/PDIF Format
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WM8581
S/PDIF TRANSMITTER
The S/PDIF transmitter generates the S/PDIF frames, and outputs on the SPDIFOP pin. The audio
data for the frame can be taken from one of four sources, selectable using the TXSRC register. The
transmitter can be powered down using the SPDIFTXD register bit. The S/PDIF Transmitter can be
bypassed by setting the REAL_THROUGH register control bit. When set, the SPDIFOP pin sources
the output of the S/PDIF input mux.
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
R30
SPDTXCHAN 0
1Eh
1:0
TXSRC[1:0]
00
S/PDIF Transmitter Data Source
00 = S/PDIF received data (see REAL_THROUGH)
01 = ADC digital output data.
10 = Secondary Audio Interface
11 = Audio Interface received data
Overwrite Channel Status
2
OVWCHAN
0
Only used if TXSRC=00. Overwrites the received
channel status data using data read from S/PDIF
transmitter channel status register
0 = Channel data equal to recovered channel data.
1 = Channel data taken from channel status registers.
S/PDIF Through Mode Control
3
4
REAL_
0
0
THROUGH
0 = SPDIFOP pin sources output of S/PDIF Transmitter
1 = SPDIFOP pins sources output of S/PDIF IN Mux
S/PDIF Transmitter Validity Overwrite Mode
TXVAL_
OVWR
0 = disabled, validity bit is 0 when transmitter sources
ADC, PAIF or SAIF, or is matches the S/PDIF input
validity when S/PDIF transmitter sources S/PDIF
receiver.
1 = enabled, validity bit transmitted for subframe 0 is
defined by TXVAL_SF0, validity bit transmitted for
subframe 1 is defined by TXVAL_SF1.
5
6
TXVAL_SF0
TXVAL_SF1
SPDIFTXD
0
0
Overwrite Mode S/PDIF Transmitter Validity Sub-
Frame 0
0 = transmit validity = 0
1 = transmit validity = 1
Overwrite Mode S/PDIF Transmitter Validity Sub-
Frame 1
0 = transmit validity = 0
1 = transmit validity = 1
R51
PWRDN 2
33h
4
1
S/PDIF Transmitter powerdown
0 = S/PDIF Transmitter enabled
1 = S/PDIF Transmitter disabled
Table 49 S/PDIF Transmitter Control
The WM8581 also transmits the preamble and VUCP bits (Validity, User Data, Channel Status and
Parity bits).
Validity Bit
By default, set to 0 (to indicate valid data) with the following exceptions:
1. TXSRC=00 (S/PDIF receiver), where Validity is the value recovered from the S/PDIF input stream by
the S/PDIF receiver.
2. TXVAL_OVWR=1, where Validity is the value set in registers TXVAL_SF0 and TXVAL_SF1.
User Data
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Set to 0 as User Data configuration is not supported in the WM8581 – if TXSRC=00 (S/PDIF
receiver) User Data is the value recovered from the S/PDIF input stream by the S/PDIF receiver.
Channel Status
The Channel Status bits form a 192-frame block - transmitted at one bit per sub-frame. Each sub-
frame forms its own 192-frame block. The WM8581 is a consumer mode device and only the first 40
bits of the block are used. All data transmitted from the WM8581 is stereo, so the channel status data
is duplicated for both channels. The only exception to this is the channel number bits (23:20) which
can be changed to indicate whether the channel is left or right in the stereo image. Bits within this
block can be configured by setting the Channel Status Bit Control registers (see Table 50 to Table
54). If TXSRC=00 (S/PDIF receiver), the Channel Status bits are transmitted with the same values
recovered by the receiver – unless OVWCHAN is set, in which case they are set by the S/PDIF
transmitter channel status registers.
Parity Bit
This bit maintains even parity for data as a means of basic error detection. It is generated by the
transmitter.
For further details of all channel status bits, refer to IEC-60958-3.
REGISTER
ADDRESS
BIT
LABEL
CHANNEL
STATUS
BIT
DEFAULT
DESCRIPTION
R31
SPDTXCHAN 1
1Fh
0
CON/PRO
0
0
0 = Consumer Mode
1 = Professional Mode (not supported by
WM8581)
1
2
AUDIO_N
CPY_N
1
0
0
0 = S/PDIF transmitted data is audio PCM.
1 = S/PDIF transmitted data is not audio
PCM.
2
0 = Transmitted data has copyright asserted.
1 = Transmitted data has no copyright
assertion.
5:3
DEEMPH[2:0]
5:3
000
000 = Data from Audio interface has no pre-
emphasis.
001 = Data from Audio interface has pre-
emphasis.
010 = Reserved (Audio interface has pre-
emphasis).
011 = Reserved (Audio interface has pre-
emphasis).
All other modes are reserved and should not
be used.
7:6
CHSTMODE
[1:0]
7:6
00
00 = Only valid mode for consumer
applications.
Table 50 S/PDIF Transmitter Channel Status Bit Control 1
REGISTER
ADDRESS
BIT
LABEL
CHANNEL
STATUS
BIT
DEFAULT
DESCRIPTION
R32
SPDTXCHAN 2
20h
7:0
CATCODE
[7:0]
15:8
00000000
Category Code. Refer to S/PDIF
specification IEC60958-3 for details.
00h indicates “general” mode.
Table 51 S/PDIF Transmitter Channel Status Bit Control 2
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REGISTER
ADDRESS
BIT
LABEL
CHANNEL
STATUS
BIT
DEFAULT
DESCRIPTION
R33
SPDTXCHAN 3
21h
3:0
5:4
SRCNUM
[3:0]
19:16
0000
00
Source Number. No definitions are attached
to data.
CHNUM1[1:0]
21:20
Channel Number for Subframe 1
CHNUM1
Function
00
01
10
11
Do not use channel number
Send to Left Channel
Send to Right Channel
Do not use channel number
7:6
CHNUM2[1:0]
00
Channel Number for Subframe 2
23:22
CHNUM2
Function
00
01
10
11
Do not use channel number
Send to Left Channel
Send to Right Channel
Do not use channel number
Table 52 S/PDIF Transmitter Channel Status Bit Control 3
REGISTER
ADDRESS
BIT
LABEL
CHANNEL
STATUS
BIT
DEFAULT
DESCRIPTION
R34
SPDTXCHAN 4
22h
3:0
FREQ[3:0]
27:24
0001
Sampling Frequency Indicated.
See S/PDIF specification IEC60958-3 for
details.
5:4
CLKACU[1:0]
29:28
11
Clock Accuracy of Transmitted clock.
00 = Level II
01 = Level I
10 = Level III
11 = Interface frame rate not matched to
sampling frequency.
Table 53 S/PDIF Transmitter Channel Status Bit Control 4
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REGISTER
ADDRESS
BIT
LABEL
CHANNEL
STATUS
BIT
DEFAULT
DESCRIPTION
R35
SPDTXCHAN 5
23h
0
MAXWL
32
1
Maximum Audio sample word length
0 = 20 bits
1 = 24 bits
3:1
TXWL[2:0]
35:33
101
Audio Sample Word Length.
000 = Word Length Not Indicated
TXWL[2:0]
001
MAXWL==1
20 bits
MAXWL==0
16 bits
010
22 bits
18 bits
100
23 bits
19 bits
101
24 bits
20 bits
110
21 bits
17 bits
All other combinations reserved
7:4
ORGSAMP
[3:0]
39:36
0000
Original Sampling Frequency. See S/PDIF
specification for details.
0000 = original sampling frequency not
indicated
Table 54 S/PDIF Transmitter Channel Status Bit Control 5
S/PDIF RECEIVER
INPUT SELECTOR
The S/PDIF receiver has one dedicated input, SPDIFIN1. This pin is a IEC-60958-3-compatible
comparator input by default or, if SPDIFIN1MODE is set, the pin will be a CMOS-compatible input.
There are three other pins which can be configured as either S/PDIF inputs or general purpose
outputs (GPOs). The four S/PDIF inputs are multiplexed to allow one input to go to the S/PDIF
receiver for decoding. The S/PDIF receiver can be powered down using the SPDIFRXD register bit.
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REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
R36
SPDMODE
24h
0
SPDIFIN1MODE
1
Selects the input circuit type for the SPDIFIN1 input
0 = CMOS-compatible input
1 = Comparator input. Compatible with 500mVpp AC
coupled consumer S/PDIF input signals as defined in
IEC60958-3.
2:1
RXINSEL[1:0]
00
S/PDIF Receiver input mux select.
The general purpose inputs must be configured using
GPOxOP to be either CMOS or comparator inputs if
selected by RXINSEL.
00 = Select SPDIFIN1
01 = Select SPDIFIN2 (MFP3)
10 = Select SPDIFIN3 (MFP4)
11 = Select SPDIFIN4 (MFP5)
S/PDIF Receiver Word Length Truncation Mask
6
WL_MASK
0
0 = disabled, data word is truncated as described in
Table 60.
1 = enabled, data word is not truncated.
GPO pin Configuration Select.
R39
GPO2
26h
3:0
7:4
GPO3OP[3:0]
GPO4OP[3:0]
0010
0011
1110 = Set GPO as S/PDIF input (CMOS-compatible
input).
1111 = Set GPO as S/PDIF input (compatible with
500mVpp AC coupled consumer S/PDIF input signals
as defined in IEC-60958-3).
R40
3:0
GPO5OP[3:0]
0100
GPO3
27h
For GPO defaults, see Table 65.
S/PDIF Receiver powerdown
0 = S/PDIF Receiver enabled
1 = S/PDIF Receiver disabled
R51
PWRDN 2
33h
5
SPDIFRXD
1
Table 55 S/PDIF Receiver Input Selection Register
AUDIO DATA HANDLING
The S/PDIF receiver recovers the data and VUCP bits from each sub-frame. If the S/PDIF input data
is in a non-compressed audio format the data can be internally routed to the stereo data input of
DAC1. The WM8581 can detect when the data is in a non-compressed audio format and will
automatically mute the DAC. See Non-Audio Detection section for more detail.
The received data can also be output over the digital audio interfaces in any of the data formats
supported. This can be performed while simultaneously using DAC1 for playback. The received data
may also be re-transmitted via the S/PDIF transmitter.
USER DATA
The WM8581 can output recovered user data received using GPO pins. See Table 65 for General
Purpose Pin control information.
CHANNEL STATUS DATA
The channel status bits are recovered from the incoming data stream and are used to control various
functions of the device. The recovered MAXWL and RXWL bits are used to truncate the recovered
24-bit audio word so that only the appropriate numbers of bits are used by the other interfaces
(except the S/PDIF transmitter which always processes the full 24-bit recovered word).
Should the recovered DEEMPH channel status be set, and the S/PDIF receiver is routed to DAC1,
the de-emphasis filter is activated for DAC1.
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The S/PDIF receiver reads channel status data from channel 1 only. The channel status data is
stored in five read-only status registers which can be read via the serial interface (see Serial Interface
Readback). When new channel status data has been recovered and stored in registers, the Channel
Status Update (CSUD) bit is set to indicate that the status registers have updated and are ready for
readback. After readback, CSUD will be cleared until the registers are next updated. The CSUD flag
can be configured to be output on any of the GPO pins. The register descriptions for the channel
status bits are given below.
REGISTER
ADDRESS
BIT
LABEL
CHANNEL
STATUS
BIT
DEFAULT
DESCRIPTION
R44
SPDRXCHAN 1
2Ch
0
CON/PRO
0
-
0 = Consumer Mode
1 = Professional Mode
The WM8581 is a consumer mode device.
Detection of professional mode may give
erroneous behaviour.
(read-only)
1
AUDIO_N
1
-
Linear PCM Identification
0 = Data word represents audio PCM
samples.
1 = Data word does not represent audio
PCM samples.
2
3
CPY_N
2
3
-
-
0 = Copyright is asserted for this data.
1 = Copyright is not asserted for this data.
DEEMPH
0 = Recovered S/PDIF data has no pre-
emphasis.
1 = Recovered S/PDIF data has pre-
emphasis.
5:4
7:6
Reserved
CHSTMODE
[1:0]
5:4
7:6
-
-
Reserved for additional de-emphasis modes.
00 = Only valid mode for consumer
applications.
Table 56 S/PDIF Receiver Channel Status Register 1
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REGISTER
ADDRESS
BIT
LABEL
CHANNEL
STATUS
BIT
DEFAULT
DESCRIPTION
R45
SPDRXCHAN 2
2Dh
7:0
CATCODE
[7:0]
15:8
-
Category Code.
Refer to S/PDIF specification IEC60958-3 for
details.
00h indicates “general” mode.
(read-only)
Table 57 S/PDIF Receiver Channel Status Register 2
REGISTER
ADDRESS
BIT
LABEL
CHANNEL
STATUS
BIT
DEFAULT
DESCRIPTION
R46
SPDRXCHAN 3
2Eh
3:0
SRCNUM
[3:0]
19:16
-
S/PDIF source number.
Refer to S/PDIF specification IEC60958-3 for
details.
5:4
7:6
CHNUM1[1:0]
21:20
-
Channel number for sub-frame 1.
(read-only)
00 = Take no account of channel number
(channel 1 defaults to left DAC)
01 = channel 1 to left channel
10 = channel 1 to right channel
Channel number for sub-frame 2.
CHNUM2[1:0]
23:22
00 = Take no account of channel number
(channel 2 defaults to left DAC)
01 = channel 2 to left channel
10 = channel 2 to right channel
Table 58 S/PDIF Receiver Channel Status Register 3
REGISTER
ADDRESS
BIT
LABEL
CHANNEL
STATUS
BIT
DEFAULT
DESCRIPTION
R47
SPDRXCHAN 4
2Fh
3:0
FREQ[3:0]
27:24
-
Sampling Frequency.
Refer to S/PDIF specification IEC60958-3 for
details.
5:4
CLKACU[1:0]
29:28
-
Clock Accuracy of received clock.
00 = Level II
(read-only)
01 = Level I
10 = Level III
11 = Interface frame rate not matched to
sampling frequency.
Table 59 S/PDIF Receiver Channel Status Register 4
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REGISTER
ADDRESS
BIT
LABEL
CHANNEL
STATUS
BIT
DEFAULT
DESCRIPTION
R48
SPDRXCHAN 5
30h
0
MAXWL
32
-
Maximum Audio sample word length
0 = 20 bits
1 = 24 bits
(read-only)
3:1
RXWL[2:0]
35:33
-
Audio Sample Word Length.
000: Word Length Not Indicated
RXWL[2:0]
001
MAXWL==1
20 bits
MAXWL==0
16 bits
010
22 bits
18 bits
100
23 bits
19 bits
101
24 bits
20 bits
110
21 bits
17 bits
All other combinations are reserved and may
give erroneous operation. Data will be
truncated internally when these bits are set
unless WL_MASK is set.
7:4
ORGSAMP
[3:0]
39:36
-
Original Sampling Frequency. Refer to
S/PDIF specification IEC60958-3 for details.
0000 = original sampling frequency not
indicated
Table 60 S/PDIF Receiver Channel Status Register 5
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S/PDIF RECEIVER STATUS FLAGS
There are several status flags generated by the S/PDIF Receiver, described below.
FLAG
DESCRIPTION
VISIBILITY
S/PDIF Status
Register, GPO
pins, SWMODE pin
(when in hardware
mode)
UNLOCK
Indicates that the S/PDIF Clock Recovery circuit is unlocked, or the
incoming S/PDIF signal is not present.
0 = Locked onto incoming S/PDIF stream.
1 = Not locked to the incoming S/PDIF stream, or incoming stream
is not present.
INVALID
Indicates that recovered S/PDIF data is marked as invalid.
0 = Data marked as valid
Interrupt Status
Register
1 = Data marked as invalid
TRANS_ERR
Indicates that recovered S/PDIF frame has parity errors or bi-phase
encoding errors, or that sub-frames were recovered out of
sequence
Interrupt Status
Register
0 = No data errors or bi-phase encoding errors detected and sub-
frame sequence correct
1 = Data errors or bi-phase encoding errors detected or subframe
sequence incorrect (missing preamble)
AUDIO_N
PCM_N
Recovered Channel Status bit-1.
Channel Status
Register, S/PDIF
Status Register
0 = Data word represents audio PCM samples.
1 = Data word does not represent audio PCM samples.
Indicates that non-audio code (defined in IEC-61937) has been
detected.
S/PDIF Status
Register
0 = Sync code not detected.
1 = Sync code detected – received data is not audio PCM.
Recovered Channel Status bit-2 (active low)
0 = Copyright is asserted for this data.
CPY_N
DEEMPH
Channel Status
Register, S/PDIF
Status Register,
GPO pins
1 = Copyright is not asserted for this data.
Recovered Channel Status bit-3
Channel Status
Register, S/PDIF
Status Register,
GPO pins
0 = Recovered S/PDIF data has no pre-emphasis.
1 = Recovered S/PDIF data has pre-emphasis
REC_FREQ[1:0]
Indicates recovered S/PDIF sample rate.
00 = Invalid
S/PDIF Status
Register
01 = 96kHz / 88.2kHz
10 = 48kHz / 44.1kHz
11 = 32kHz
INT_N
Interrupt signal (see section Interrupt Generation)
Recovered validity-bit for current sub-frame
Recovered user-bit for current sub-frame
Recovered channel-bit for current sub-frame
Recovered parity-bit for current sub-frame
Indicates current sub-frame:
GPO pins
GPO pins
GPO pins
GPO pins
GPO pins
GPO pins
V
U
C
P
SFRM_CLK
1 = Sub-frame A
0 = Sub-frame B
192BLK
CSUD
Indicates start of 192 frame-block. High for duration of frame-0.
GPO pins
GPO pins
Indicates that the 192 frame-block of channel status data has
updated.
ZFLAG
Indicates ‘zero-detection’ in DACs. See page 45 for more details
MUTE pin, GPO
pins
NON_AUDIO
Logical OR of PCM_N and AUDIO_N
GPO pins, SDO pin
(when in hardware
mode)
Table 61 Status Flag Description
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HARDWARE INTERRUPT GENERATION (INT_N)
The hardware interrupt INT_N flag (active low) indicates that a change in status has occurred on one
or more of the UNLOCK, INVALID, TRANS_ERR, NON_AUDIO, CPY_N, DEEMPH, CSUD or
REC_FREQ flags. To determine which flag caused the interrupt, the Interrupt Status Register
(INTSTAT) should be read when INT_N is asserted. INVALID, TRANS_ERR and CSUD generate an
interrupt when the flag transitions from low to high. UNLOCK, NON_AUDIO, CPY_N, DEEMPH and
REC_FREQ will generate an interrupt on any change in status. INT_N will remain asserted until it is
cleared by reading the interrupt status register. If INVALID, TRANS_ERR or CSUD are still active
when the interrupt status register is read, INT_N remains asserted.
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
R43
INTSTAT
2Bh
0
UPD_UNLOCK
-
UNLOCK flag update signal
0 = INT_N not caused by update to UNLOCK flag
1 = INT_N caused by update to UNLOCK flag
INVALID flag interrupt signal
(read-only)
1
2
3
4
5
6
7
INT_INVALID
INT_CSUD
-
-
-
-
-
-
-
0 = INT_N not caused by INVALID flag
1 = INT_N caused by INVALID flag
CSUD flag interrupt signal
0 = INT_N not caused by CSUD flag
1 = INT_N caused by CSUD flag
INT_TRANS
_ERR
TRANS_ERR flag interrupt signal
0 = INT_N not caused by TRANS_ERR flag
1 = INT_N caused by TRANS_ERR flag
NON_AUDIO update signal
UPD_NON_AUDIO
UPD_CPY_N
0 = INT_N not caused by update to NON_AUDIO flag
1 = INT_N caused by update to NON_AUDIO flag
CPY_N update signal
0 = INT_N not caused by update to CPY_N flag
1 = INT_N caused by update to CPY_N flag
DEEMPH update signal
UPD_DEEMPH
UPD_REC_FREQ
0 = INT_N not caused by update to DEEMPH flag
1 = INT_N caused by update to DEEMPH flag
REC_FREQ update signal
0 = INT_N not caused by update to REC_FREQ flag
1 = INT_N caused by update to REC_FREQ flag
Table 62 Interrupt Status Register
Where the INT_N has been asserted due to an updated status signal (UPD_UNLOCK,
UPD_NON_AUDIO, UPD_CPY_N, UPD_DEEMPH, UPD_REC_FREQ) the S/PDIF Status Register
SPDSTAT, register R49, can be read to reveal the status of the flag. See Table 63 The SPDSTAT
register will update if the received Rx S/PDIF data stream changes their values.
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REGISTER
WM8581
BIT
LABEL
DEFAULT
DESCRIPTION
ADDRESS
R49
0
AUDIO_N
-
Recovered Channel Status bit-1.
SPDSTAT
31h
0 = Data word represents audio PCM samples.
1 = Data word does not represent audio PCM samples.
(read-only)
1
PCM_N
-
Indicates that non-audio code (defined in IEC-61937)
has been detected.
0 = Sync code not detected.
1 = Sync code detected – received data is not audio
PCM.
2
3
CPY_N
-
-
Recovered Channel Status bit-2 (active low).
0 = Copyright is asserted for this data.
1 = Copyright is not asserted for this data.
Recovered Channel Status bit-3
0 = Recovered S/PDIF data has no pre-emphasis.
1 = Recovered S/PDIF data has pre-emphasis
Indicates recovered S/PDIF clock frequency:
00 = Invalid
DEEMPH
5:4
REC_FREQ
[1:0]
--
01 = 96kHz / 88.2kHz
10 = 48kHz / 44.1kHz
11 = 32kHz
6
UNLOCK
-
Indicates that the S/PDIF Clock Recovery circuit is
unlocked or that the input S/PDIF signal is not present.
0 = Locked onto incoming S/PDIF stream.
1 = Not locked to the incoming S/PDIF stream or the
incoming S/PDIF stream is not present.
Table 63 S/PDIF Status Register
The interrupt and update signals used to generate INT_N can be masked as necessary. The MASK
register bit prevents flags from asserting INT_N and from updating the Interrupt Status Register
(R43). Masked flags update the S/PDIF Status Register (R49).
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
R37
INTMASK
25h
8:0
MASK[8:0]
000000000
When a flag is masked, it does not update the Interrupt
Status Register or assert INT_N.
0 = unmask, 1 = mask.
MASK[0] = mask control for UPD_UNLOCK
MASK[1] = mask control for INT_INVALID
MASK[2] = mask control for INT_CSUD
MASK[3] = mask control for INT_TRANS_ERR
MASK[4] = mask control for UPD_AUDIO_N
MASK[5] = mask control for UPD_PCM_N
MASK[6] = mask control for UPD_CPY_N
MASK[7] = mask control for UPD_DEEMPH
MASK[8] = mask control for UPD_REC_FREQ
Table 64 Interrupt Mask Control Register
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ERROR HANDLING IN SOFTWARE MODE
When the TRANS_ERR flag is asserted, the recovered S/PDIF sub-frame is corrupted. When the
INVALID flag is asserted, the recovered S/PDIF sub-frame is marked as being invalid.
The S/PDIF receiver has two modes of error handling for these errors, manual and automatic. The
mechanism for each flag is similar and is described below.
MANUAL ERROR HANDLING
When the flag is not masked using the MASK register, the recovered S/PDIF data is passed to the
digital audio interface and DAC1 or to the S/PDIF transmitter (note 1) irrespective of the state of the
flag and the data content of the recovered stream. In this case the application processor will be
interrupted via the INT_N signal and appropriate action should be taken by the application processor
to handle the error condition.
AUTOMATIC ERROR HANDLING
When the flag is masked using the MASK register, the WM8581 will automatically overwrite the
recovered S/PDIF data with either all-zeros or the last valid data sample depending on the status of
FILLMODE. In this case the application processor will not be interrupted via the INT_N signal and
appropriate action will be taken by the WM8581 to handle the error condition.
The automatic error handling can be disabled for the INVALID flag if the ‘ALWAYSVALID’ bit is set. In
this case, recovered data which is marked as invalid will be allowed to pass to the digital audio
interface or to the S/PDIF transmitter.
Notes
1. For the S/PDIF receiver to S/PDIF transmitter data path, only the INVALID flag will cause data to
be overwritten, the TRANS_ERR flag is not used to overwrite data which is passed to the
S/PDIF transmitter.
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
R38
GP01
26h
8
FILLMODE
0
Fill Mode Overwrite Configuration
Determines S/PDIF receiver action when TRANS_ERR or
INVALID flag is masked and error condition sets the flag:
0 = Data from S/PDIF receiver is overwritten with last valid
data sample when flag is set.
1 = Data from S/PDIF receiver is overwritten as all zeros
when flag is set.
8
ALWAYSVALID
0
Automatic Error Handling Configuration for INVALID
Flag
R39
GP02
27h
0 = INVALID flag automatic error handling enabled.
1 = INVALID flag automatic error handling disabled.
Table 65 S/PDIF Receiver Automatic Error Handling Configuration Registers
NON-AUDIO DETECTION
Non-Audio data is indicated by the AUDIO_N and PCM_N flags. AUDIO_N is recovered from the
Channel Status block. PCM_N is set on detection of the 96-bit IEC-61937 non-audio data sync code,
embedded in the data section of the S/PDIF frame. If DAC1 is sourcing the S/PDIF Receiver and
either the AUDIO_N or PCM_N flags are asserted, DAC1 is automatically muted using the softmute
feature. As described above, any change of AUDIO_N or PCM_N status will cause an INT_N
interrupt (UPD_NON_AUDIO) to be generated. If the MASK register bit for AUDIO_N or PCM_N is
set, then the associated signal will not generate an interrupt (UPD_NON_AUDIO) but the DAC will be
muted.
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WM8581
S/PDIF INPUT/ GPO PIN CONFIGURATION
The WM8581 has seven pins which can be configured as GPOs using the registers shown in Table
65. The GPO pins can be used to output status data decoded by the S/PDIF receiver. These same
pins may be used as S/PDIF inputs as described in Table 55.
REGISTER
BIT
LABEL
DEFAULT
DESCRIPTION
ADDRESS
R38
3:0
7:4
GPO1OP[3:0]
GPO2OP[3:0]
0000
0001
0000 = INT_N
0001 = V
GPO1
26h
0010 = U
0011 = C
R39
3:0
7:4
GPO3OP[3:0]
GPO4OP[3:0]
0010
0011
0100 = P
GPO2
27h
0101 = SFRM_CLK
0110 = 192BLK
0111 = UNLOCK
1000 = CSUD
1001 = Invalid
1010 = ZFLAG
1011 = NON_AUDIO
1100 = CPY_N
1101 = DEEMP
R40
3:0
7:4
GPO5OP[3:0]
GPO6OP[3:0]
0100
0101
GPO3
28h
R41
3:0
GPO7OP[3:0]
0110
GPO4
29h
1110 = Set GPO as S/PDIF input (CMOS-compatible
input). Only applicable for GPO3/4/5.
1111 = Set GPO as S/PDIF input (‘comparator’ input for
AC coupled consumer S/PDIF signals). Only applicable
for GPO3/4/5
Table 65 GPO Control Registers
POWERDOWN MODES
The WM8581 has powerdown control bits allowing specific parts of the chip to be turned off when not
in use.
The ADC is powered down by setting the ADCPD register bit. The three stereo DACs each have a
separate powerdown control bit, DACPD[2:0], allowing individual stereo DACs to be powered down
when not in use. DACPD can be overwritten by setting ALLDACPD to powerdown all DACs
The S/PDIF transmitter is powered down by setting SPDIFTXD. Setting SPDIFRXD powers down the
S/PDIF receiver.
The PLL, Oscillator and S/PDIF clock recovery circuits are powered down by setting PLLPD, OSCPD
and SPDIFPD respectively.
Setting all of ADCPD, DACPD[2:0], SPDIFTXD, SPDIFRXD and OUTPD[3:0] will powerdown
everything except the references VMIDADC, ADCREF and VMIDDAC. These may be powered down
by setting PWDN. Setting PWDN will override all other powerdown control bits. It is recommended
that the ADC and DAC are powered down before setting PWDN. The default is for all powerdown bits
to be set except OSCPD and PWDN.
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REGISTER ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
R50
PWRDN 1
32h
0
PWDN
0
Master powerdown (overrides all
powerdown registers)
0 = All digital circuits running,
outputs are active
1 = All digital circuits in power
down mode, outputs muted
1
ADCPD
1
ADC powerdown
0 = ADC enabled
1 = ADC disabled
DAC powerdowns
0 = DAC enabled
1 = DAC disabled
DACPD[0] = DAC1
DACPD[1] = DAC2
DACPD[2] = DAC3
Overrides DACPD[3:0]
4:2
DACPD[2:0]
111
6
0
ALLDACPD
OSCPD
1
0
0 = DACs under control of
DACPD[3:0]
1= All DACs are disabled.
OSC output powerdown
0 = OSC output enabled
1 = OSC output disabled
R51
PWRDN 2
33h
A CMOS input can be applied to
the OSC input when powered
down.
1
2
3
PLLAPD
PLLBPD
SPDIFPD
1
1
1
0 = PLLA enabled
1 = PLLA disabled
0 = PLLB enabled
1 = PLLB disabled
S/PDIF Clock Recovery
PowerDown
0 = S/PDIF enabled
1 = S/PDIF disabled
4
5
SPDIFTXD
SPDIFRXD
1
1
S/PDIF Transmitter powerdown
0 = S/PDIF Transmitter enabled
1 = S/PDIF Transmitter disabled
S/PDIF Receiver powerdown
0 = S/PDIF Receiver enabled
1 = S/PDIF Receiver disabled
Table 66 Powerdown Registers
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INTERNAL POWER ON RESET CIRCUIT
Figure 34 Internal Power On Reset Circuit Schematic
The WM8581 includes an internal Power-On Reset Circuit, which is used to reset the digital logic into
a default state after power up.
Figure 34 shows a schematic of the internal POR circuit. The POR circuit is powered from AVDD.
The circuit monitors DVDD and VMID and asserts PORB low if DVDD or VMID are below the
minimum threshold Vpor_off.
On power up, the POR circuit requires AVDD to be present to operate. PORB is asserted low until
AVDD, DVDD and VMID voltages have risen above their reset thresholds. When these three
conditions have been met, PORB is released high. When PORB is released high, all registers are in
their default state and writes to the digital interface may take place.
On power down, PORB is asserted low whenever DVDD or VMID drop below the minimum threshold
Vpor_off.
If AVDD is removed at any time, the internal Power On Reset circuit is powered down and the PORB
output will follow the AVDD voltage.
In most applications, the time required for the device to release PORB high will be determined by the
charge time of the VMID node.
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Figure 35 Typical Power up sequence where DVDD is powered before AVDD
Figure 36 Typical Power up sequence where AVDD is powered before DVDD
SYMBOL
Vpora
MIN
0.5
0.5
1.0
0.6
TYP
0.7
0.7
1.4
0.8
MAX
1.0
UNIT
V
V
V
V
Vporr
1.1
Vpora_off
Vpord_off
2.0
1.0
Table 67 Typical POR Operation
In a real application, the designer is unlikely to have control of the relative power up sequence of
AVDD and DVDD. Using the POR circuit to monitor VMID ensures a reasonable delay between
applying power to the device and Device Ready.
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Figure 35 and Figure 36 show typical power up scenarios in a real system. Both AVDD and DVDD
must be established, and VMID must have reached the threshold Vporr before the device is ready
and can be written to. Any writes to the device before Device Ready will be ignored.
Figure 35 shows DVDD powering up before AVDD. Figure 36 shows AVDD powering up before
DVDD. In both cases, the time from applying power to Device Ready is dominated by the charge time
of VMID.
A 4.7µF capacitor (minimum) is recommended for decoupling on VMID. The charge time for VMID
will dominate the time required for the device to become ready after power is applied. The time
required for VMID to reach the threshold is a function of the VMID resistor string and the decoupling
capacitor. To reduce transient audio effects during power on, the stereo DACs on the WM8581 have
their outputs clamped to VMID at power-on. This increases the capacitive loading of the VMID
resistor string, as the DAC output AC coupling capacitors must be charged to VMID, and hence the
required charge time. To ensure minimum device startup time, the VMIDSEL bit is set by default,
thus reducing the impedance of the resistor string. If required, the VMID string can be restored to a
high impedance state to save power once the device is ready.
REGISTER ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
R29
ADC CONTROL 1
1Dh
8
VMIDSEL
1
VMID Impedance Selection
0 = High impedance, power
saving
1 = Low impedance, fast power-
on
DEVICE ID READBACK
Reading from registers R0, R1 and R2 returns the device ID and revision number. R0 returns 80h, R1
returns 85h, R2 returns the device revision number. Device ID readback is not possible in continuous
readback mode (CONTREAD=1).
HARDWARE CONTROL MODE
The WM8581 can be controlled in Hardware Control Mode or Software Control Mode. The method of
control is determined by the state of the HWMODE pin. If the HWMODE pin is low, Software Control
Mode is selected. If the HWMODE pin is high, Hardware Control Mode is selected.
In Hardware Control Mode the user has limited control over the features of the WM8581. Most of the
features will assume their default settings but some can be modified using external pins.
HWMODE
SWMODE
0
1
0
1
Software Control Hardware Control
2-wire control
3-wire control
Table 68 Hardware/Software Mode Setup
DIGITAL ROUTING CONTROL
See page 25 for a more detailed explanation of the Digital Routing Options within the WM8581. In
Software Control Mode, the values of register bits DAC_SRC, PAIFTX_SRC and TXSRC configure
the signal path routing between interfaces. In hardware mode, similar control can be achieved via
pins DR1, DR2, DR3 and DR4 as detailed in Table 69 and Table 70.
PIN
DR1
DR2
0
1
DAC_SRC=S/PDIF receiver
DAC_SRC=PAIF receiver
PAIFTX_SRC=ADC output
PAIFTX_SRC=S/PDIF
receiver
Table 69 DR1 / DR2 Operation
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DR4
DR3
S/PDIF TRANSMITTER
DATA SOURCE
S/PDIF received data
ADC digital output data
Not available.
0
0
1
1
0
1
0
1
PAIF receiver data
Table 70 DR3 / DR4 Operation
The Secondary Audio Interface (SAIF) is not operational in Hardware Mode.
STATUS PINS
In Hardware control mode, SDO and SWMODE pins provide S/PDIF status flag information.
FLAG
DESCRIPTION
PIN
SWMODE
UNLOCK
Indicates that the S/PDIF Clock Recovery circuit is unlocked
or that the input S/PDIF signal is not present.
0 = Locked to incoming S/PDIF stream.
1 = Not locked to the incoming S/PDIF stream, or incoming
stream not present.
SDO
NON_AUDIO
Logical OR of PCM_N and AUDIO_N:
PCM_N indicates that non-audio code (defined in IEC-61937)
has been detected. AUDIO_N is the recovered Channel
Status bit-1.
Table 71 Hardware Mode Status Pins
DIGITAL AUDIO INTERFACE CONTROL
In Hardware Control Mode, CSB and SCLK become controls to configure the Primary Audio Interface
data format and word length. The configuration applies to both transmit and receive sides of the
interface. Table 72 below shows the options available.
CSB
SCLK
FORMAT & WORD LENGTH
24-bit right justified
20-bit right justified
24-bit left justified
24-bit I2S
0
0
1
1
0
1
0
1
Table 72 Audio Interface Hardware Mode Control
DAC MUTE CONTROL
In Hardware Control mode, the MUTE pin activates the softmute function on all the DACs. In
Software Control mode, MUTE activates softmute on the DAC selected by the DZFM register (when
the MPDENB bit is low). See page 37 for a detailed description of the softmute function and the
other methods of activating softmute.
When floating, the MUTE pin becomes an output for the ZFLAG flag.
DESCRIPTION
MUTE
0
1
Normal Operation
Mute DAC channels
Floating
MUTE is an output to indicate when Zero Detection occurs on all DACs
(ZFLAG).
H = detected, L = not detected.
Table 73 MUTE Pin Control Options
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WM8581
PRIMARY AUDIO INTERFACE (TX) MASTER MODE CONTROL
In Hardware Control Mode, the SDIN pin is used to enable the master mode function on the Primary
Audio Interface transmitter. This has the same operation as the PAIFTX_MS register bit. The
PAIFTX_RATE default settings of 256fs, and 64 BCLKs/LRCLK for BCLKSEL, are used in Hardware
Control Mode. See page Error! Bookmark not defined. for more information on master mode
operation.
SDIN
AUDIO INTERFACE (TX)
0
1
Slave
Master
Table 74 Audio Interface (Transmitter) Master Mode Hardware Mode Control
POWERDOWN CONTROL
In Software Control Mode, the device is powered-down by default. In Hardware Control Mode, the
chip is powered-up by default but can be powered down by setting the ALLPD(MFP7) input high.
(Note that in Software Control Mode, this pin takes the function of SAIF_LRCLK or GPO7).
ALLPD (MFP7)
0
1
Powerup
Powerdown
Table 75 Hardware Mode Powerdown Control
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REGISTER MAP
The complete register map is shown below. The detailed description can be found in the relevant text of the device description. The
WM8581 can be configured using the Control Interface. All unused bits should be set to ‘0’.
REGISTER NAME
ADDRESS
B8
B7
B6
B5
B4
B3
B2
B1
B0
DEFAULT
R0
00
01
02
03
04
05
06
07
PLLA 1/DEVID1
PLLA_K[8:0]
PLLA_K[17:9]
100100001
101111110
001111101
000010100
100100001
101111110
001111101
110010100
R1
R2
R3
R4
R5
R6
R7
PLLA 2/DEVID2
PLLA 3/DEVREV
PLLA 4
0
0
PLLA_N[3:0]
0
PLLA_K[21:18]
FREQMODE_A[1:0]
0
0
1
POSTSCALE_A PRESCALE_A
PLLB 1
PLLB_K[8:0]
PLLB_K[17:9]
PLLB 2
PLLB 3
0
PLLB_N[3:0]
PLLB_K[21:18]
MCLKOUTSRC[1:0]
FREQMODE_B[1:0]
PLLB 4
CLKOUTSRC[1:0]
1
POSTSCALE_B PRESCALE_B
CLKSEL
_MAN
08
0
0
0
TX_CLKSEL[1:0]
ADC_CLKSEL[1:0]
PAIFRX_BCLKSEL[1:0]
PAIFRX_RATE[2:0]
DAC_CLKSEL[1:0]
000010000
R8
CLKSEL
R9
09
0A
0B
0C
0D
0E
0F
10
11
12
13
PAIFRXMS_CLKSEL[1:0]
PAIFRXMS
PAIF 1
PAIF 2
000000010
000000010
011000010
110001010
010001010
000001010
011100100
000001001
000000000
011111111
000000000
R10
R11
R12
R13
R14
R15
R16
R17
R18
R19
PAIFTX_BCLKSEL[1:0]
0
0
0
PAIFTXMS
SAIFMS
PAIFRXBCP
PAIFTXBCP
PAIFTX_RATE[2:0]
SAIF_RATE[2:0]
SAIF_BCLKSEL[1:0]
SAIF 1
0
SAIFMS_CLKSEL[1:0]
PAIFRXLRP
PAIFTXLRP
SAIFLRP
PAIFRXWL[1:0]
PAIFRXFMT[1:0]
PAIF 3
DAC_SRC[1:0]
PAIFTX_SRC[1:0]
SAIFTX_SRC[1:0]
DACOSR
0
PAIFTXWL[1:0]
SAIFWL[1:0]
PAIFTXFMT[1:0]
SAIFFMT[1:0]
DAC1SEL[1:0]
PAIF 4
SAIFBCP
SAIF 2
SAIF_EN
DAC4SEL[1:0]
DAC3SEL[1:0]
DAC2SEL[1:0]
DAC CONTROL 1
DAC CONTROL 2
DAC CONTROL 3
DAC CONTROL 4
DAC CONTROL 5
RX2DAC_MODE
0
0
0
0
IZD
0
DZFM[2:0]
0
PL[3:0]
0
DEEMP[3:0]
DEEMPALL
PHASE[7:0]
MUTEALL
LDA1[7:0]
MPDENB DACATC
DZCEN
DMUTE[3:0]
DIGITAL ATTENUTATION
DACL 1
UPDATE
UPDATE
UPDATE
UPDATE
UPDATE
UPDATE
UPDATE
UPDATE
R20
R21
R22
R23
R24
R25
R26
R27
14
15
16
17
18
19
1A
1B
011111111
011111111
011111111
011111111
011111111
011111111
DIGITAL ATTENUTATION
DACR 1
RDA1[7:0]
LDA2[7:0]
RDA2[7:0]
LDA3[7:0]
RDA3[7:0]
LDA4[7:0]
RDA4[7:0]
MASTDA[7:0]
DIGITAL ATTENUTATION
DACL 2
DIGITAL ATTENUTATION
DACR 2
DIGITAL ATTENUTATION
DACL 3
DIGITAL ATTENUTATION
DACR 3
DIGITAL ATTENUTATION
DACR 4
011111111
011111111
011111111
DIGITAL ATTENUTATION
DACR 4
MASTER DIGITAL
ATTENUTATION
UPDATE
VMIDSEL
R28
R29
R30
1C
1D
1E
ADC CONTROL 1
SPDTXCHAN 0
ADCRATE[2:0]
ADCHPD ADCOSR AMUTEALL AMUTER AMUTEL 101000000
TXVAL_
SF1
TXVAL_ TXVAL_
SF0 OVWR
REAL_
0
0
0
0
0
0
0
TXSRC[1:0]
000000010
OVWCHAN
THROUGH
CHSTMODE[1:0]
DEEMPH[2:0]
CATCODE[7:0]
CHNUM1[1:0]
CLKACU[1:0]
ORGSAMP[3:0]
CPY_N AUDIO_N CON/PRO
R31
R32
R33
R34
R35
1F
20
21
22
23
SPDTXCHAN 1
SPDTXCHAN 2
SPDTXCHAN 3
SPDTXCHAN 4
SPDTXCHAN 5
000000000
000000000
CHNUM2[1:0]
SRCNUM[3:0]
FREQ[3:0]
000000000
000110001
000001011
0
0
TXWL[2:0]
MAXWL
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R36
WM8581
24
25
26
27
28
29
2A
2B
2C
2D
2E
2F
30
31
32
33
SPDMODE
0
0
WL_MASK
1
1
1
RXINSEL[1:0]
000111001
SPDIFIN1MODE
R37
R38
R39
R40
R41
R42
R43
R44
R45
R46
R47
R48
R49
R50
R51
INTMASK
GPO1
MASK[8:0]
000000000
GPO2OP[3:0]
GPO1OP[3:0]
GPO30P[3:0]
GPO5OP[3:0]
GPO70P[3:0]
000010000
FILLMODE
GPO2
GPO4OP[3:0]
GPO6OP[3:0]
000110010
ALWAYSVALID
GPO3
0
0
0
001010100
GPO4
0
1
1
0
1
0
1
1
001110110
Reserved
1
0
0
0
010011000
INTSTAT
Error Flag Interupt Status Register
Channel Status Register 1
Channel Status Register 2
Channel Status Register 3
Channel Status Register 4
Channel Status Register 5
S/PDIF Status Register
DACPD[3:0]
-
SPDRXCHAN 1
SPDRXCHAN 2
SPDRXCHAN 3
SPDRXCHAN 4
SPDRXCHAN 5
SPDSTAT
PWRDN 1
PWRDN 2
-
-
-
-
-
-
0
0
ALLDACPD
ADCPD
PWDN
001111110
000111110
0
0
0
0
0
0
SPDIFRXD
0
SPDIFPD PLLBPD PLLAPD
OSCPD
SPDIFTXD
READEN
CONTREAD
READMUX[2:0]
R52
R53
34
35
READBACK
RESET
000000000
n/a
RESET
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
Fractional (K) part of PLLA frequency ratio (R).
R0
PLLA 1/
DEVID1
00h
8:0
PLLA_K[8:0]
100100001
Value K is one 22-digit binary number spread over registers R0,
R1 and R2 as shown.
Reading from these registers will return the device ID.
R0 returns 10000001 = 81h
R1
8:0
PLLA_K[17:9]
101111110
PLLA 2/
DEVID2
01h
R1 returns 10000101 = 85h
Device ID readback is not possible in continuous readback mode
(CONTREAD=1).
R2
3:0
7:4
PLLA_K[21:18]
PLLA_N[3:0]
1101
0111
PLLA 3/
DEVREV
02h
Integer (N) part of PLLA frequency ratio (R).
Use values in the range 5 ≤ PLLA_N ≤ 13 as close as possible to
8.
Reading from this register will return the device revision number.
PLL Pre-scale Divider Select
R3
PLLA 4
03h
0
1
PRESCALE_A
0
0
0 = Divide by 1 (PLL input clock = oscillator clock)
1 = Divide by 2 (PLL input clock = oscillator clock ÷ 2)
Note: PRESCALE_A must be set to the same value as
PRESCALE_B in PLL S/PDIF receiver mode.
POSTSCALE_A
PLL Post-scale Divider Select
PLL S/PDIF Receiver Mode
POSTSCALE_A is used to configure a 256fs or 128fs PLLACLK,
POSTSCALE_B is not used. Refer to Table 45.
PLL User Mode
Used in conjunction with the FREQMODE_x bits. Refer to Table
44.
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REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
4:3
FREQMODE_A[
1:0]
10
PLL Output Divider Select
PLL S/PDIF Receiver Mode
FREQMODE_A is automatically controlled. FREQMODE_B is not
used.
PLL User Mode
Used in conjunction with the POSTSCALE_x bits. Refer to Table
44.
R4
PLLB 1
04h
8:0
8:0
PLLB_K[8:0]
100100001
101111110
Fractional (K) part of PLLB frequency ratio (R).
Value K is one 22-digit binary number spread over registers R4,
R5 and R6 as shown.
Note: PLLB_K must be set to specific values when the S/PDIF
receiver is used. Refer to S/PDIF Receive Mode Clocking
section for details.
R5
PLLB_K[17:9]
PLLB 2
05h
R6
3:0
7:4
PLLB_K[21:18]
PLLB_N[3:0]
1101
0111
PLLB 3
06h
Integer (N) part of PLL B frequency ratio (R).
Use values in the range 5 ≤ PLLB_N ≤ 13 as close as possible to
8
Note: PLLB_N must be set to specific values when the S/PDIF
receiver is used. Refer to S/PDIF Receive Mode Clocking
section for details.
R7
PLLB 4
07h
0
1
PRESCALE_B
0
0
PLL Pre-scale Divider Select
0 = Divide by 1 (PLL input clock = oscillator clock)
1 = Divide by 2 (PLL input clock = oscillator clock ÷ 2)
Note: PRESCALE_A must be set to the same value as
PRESCALE_B in PLL S/PDIF receiver mode.
POSTSCALE_B
PLL Post-scale Divider Select
PLL S/PDIF Receiver Mode
POSTSCALE_A is used to configure a 256fs or 128fs PLLACLK,
POSTSCALE_B is not used. Refer to Table 45.
PLL User Mode
Used in conjunction with the FREQMODE_x bits. Refer to Table
44.
4:3
FREQMODE_B
[1:0]
10
PLL Output Divider Select
PLL S/PDIF Receiver Mode
FREQMODE_A is automatically controlled. FREQMODE_B is not
used.
PLL User Mode
Used in conjunction with the POSTSCALE_x bits. Refer to Table
44.
6:5
8:7
1:0
MCLKOUTSRC
CLKOUTSRC
DAC_CLKSEL
00
11
00
MCLK pin output source
00 = Input – Source MCLK pin
01 = Output – Source PLLACLK
10 = Output – Source PLLBCLK
11 = Output – Source OSCCLK
CLKOUT pin source
00 = No Output (tristate)
01 = Output – Source PLLACLK
10 = Output – Source PLLBCLK
11 = Output – Source OSCCLK
DAC clock source
R8
CLKSEL
08h
00 = MCLK pin
01 = PLLACLK
10 = PLLBCLK
11 = MCLK pin
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REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
3:2
ADC_CLKSEL
00
ADC clock source
00 = ADCMLCK pin
01 = PLLACLK
10 = PLLBCLK
11 = MCLK pin
5:4
TX_CLKSEL
01
S/PDIF Transmitter clock source
00 = ADCMLCK pin
01 = PLLACLK
10 = PLLBCLK
11 = MCLK pin
6
CLKSEL_MAN
0
Clock selection auto-configuration override
0 = auto-configuration enabled, clock configuration follows
restrictions described in page 43 to page 48.
1 = auto-configuration disabled, clock configuration follows
relevant CLKSEL bits in R8 to R11.
R9
PAIF 1
09h
2:0
PAIFRX_RATE
[2:0]
010
Master Mode LRCLK Rate
000 = 128fs
001 = 192fs
010 = 256fs
011 = 384fs
100 = 512fs
101 = 768fs
110 = 1152fs
4:3 PAIFRX_BCLKSEL
[1:0]
00
Master Mode BCLK Rate
00 = 64 BCLKs per LRCLK
01 = 32 BCLKs per LRCLK
10 = 16 BCLKs per LRCLK
11 = BCLK = System Clock
PAIF Receiver Master/Slave Mode Select
0 = Slave Mode
5
PAIFRXMS
0
1 = Master Mode
7:6
PAIFRXMS_
CLKSEL
00
PAIF Receiver Master Mode clock source
00 = MCLK pin
01 = PLLACLK
10 = PLLBCLK
11 = MCLK pin
R10
PAIF 2
0Ah
2:0
PAIFTX_RATE
[2:0]
010
Master Mode LRCLK Rate
000 = 128fs
001 = 192fs
010 = 256fs
011 = 384fs
100 = 512fs
101 = 768fs
110 = 1152fs
4:3 PAIFTX_BCLKSEL
[1:0]
00
Master Mode BCLKRate
00 = 64 BCLKs per LRCLK
01 = 32 BCLKs per LRCLK
10 = 16 BCLKs per LRCLK
11 = BCLK = System Clock
5
PAIFTXMS
0
PAIF Transmitter Master/Slave Mode Select:
0 = Slave Mode
1 = Master Mode
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Production Data
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
R11
SAIF1
0Bh
2:0
SAIF_RATE
[2:0]
010
Master Mode LRCLK Rate
000 = 128fs
001 = 192fs
010 = 256fs
011 = 384fs
100 = 512fs
101 = 768fs
110 = 1152fs
4:3
SAIF_BCLKSEL
[1:0]
00
Master Mode BCLK Rate
00 = 64 BCLKs per LRCLK
01 = 32 BCLKs per LRCLK
10 = 16 BCLKs per LRCLK
11 = BCLK = System Clock
5
SAIFMS
0
SAIF Master/Slave Mode Select
0 = Slave Mode
1 = Master Mode
7:6
SAIFMS_
CLKSEL
[1:0]
11
SAIF Master Mode clock source
00 = ADCMCLK pin
01 = PLLACLK
10 = PLLBCLK
11 = MCLK pin
R12
PAIF 3
0Ch
1:0
3:2
4
PAIFRXFMT
[1:0]
10
10
0
PAIF Receiver Audio Data Format Select
11: DSP Format
10: I2S Format
01: Left justified
00: Right justified
PAIFRXWL
[1:0]
PAIF Receiver Audio Data Word Length
11: 32 bits (see Note)
10: 24 bits
01: 20 bits
00: 16 bits
PAIFRXLRP
In LJ/RJ/I2S modes
0 = LRCLK not inverted
1 = LRCLK inverted
In DSP Format:
0 = DSP Mode A
1 = DSP Mode B
5
6
PAIFRXBCP
DACOSR
0
0
PAIF Receiver BCLK polarity
0 = BCLK not inverted
1 = BCLK inverted
DAC Oversampling Rate Control
0= 128x oversampling
1= 64x oversampling
8:7
DAC_SRC
[1:0]
11
DAC1 Source:
00 = S/PDIF received data.
10 = SAIF Receiver data
11 = PAIF Receiver data
Note: When DAC_SRC = 00, DAC2/3/4 may be turned off,
depending on RX2DAC_MODE
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WM8581
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
R13
PAIF 4
0Dh
1:0
PAIFTXFMT
[1:0]
10
PAIF Transmitter Audio Data Format Select
11: DSP Format
10: I2S Format
01: Left justified
00: Right justified
3:2
PAIFTXWL
[1:0]
10
PAIF Transmitter Audio Data Word Length
11: 32 bits (see Note)
10: 24 bits
01: 20 bits
00: 16 bits
4
PAIFTXLRP
0
In LJ/RJ/I2S modes
0 = LRCLK not inverted
1 = LRCLK inverted
In DSP Format:
0 = DSP Mode A
1 = DSP Mode B
5
PAIFTXBCP
0
PAIF Receiver BCLK polarity
0 = BCLK not inverted
1 = BCLK inverted
8:7
PAIFTX_SRC
[1:0]
01
Primary Audio Interface Transmitter Source
00 = S/PDIF received data.
01 = ADC digital output data.
10 = SAIF Receiver data
SAIF Audio Data Format Select
11: DSP Format
R14
SAIF 2
0Eh
1:0
3:2
4
SAIFFMT
[1:0]
10
10
0
10: I2S Format
01: Left justified
00: Right justified
SAIFWL
[1:0]
SAIF Audio Data Word Length
11: 32 bits (see Note)
10: 24 bits
01: 20 bits
00: 16 bits
SAIFLRP
In LJ/RJ/I2S modes
0 = LRCLK not inverted
1 = LRCLK inverted
In DSP Format:
0 = DSP Mode A
1 = DSP Mode B
5
6
SAIFBCP
SAIF_EN
0
0
SAIF BCLK polarity
0 = BCLK not inverted
1 = BCLK inverted
SAIF Enable
0 = SAIF disabled
1 = SAIF enabled
8:7
SAIFTX_SRC
[1:0]
00
Secondary Audio Interface Transmitter Source
00 = S/PDIF received data.
01 = ADC digital output data.
11 = PAIF Receiver data
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Production Data
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
R15
1:0
DAC1SEL
[1:0]
00
DAC digital input select
DAC
CONTROL
1
00 = DAC takes data from DIN1
01 = DAC takes data from DIN2
10 = DAC takes data from DIN3
11 = DAC takes data from DIN4
3:2
5:4
7:6
8
DAC2SEL
[1:0]
01
10
11
0
0Fh
DAC3SEL
[1:0]
DAC4SEL
[1:0]
RX2DAC_MODE
DAC oversampling rate and power down control (only valid when
DAC_SRC = 00, S/PDIF receiver)
0 = SFRM_CLK determines oversampling rate, DACs 2/3
powered down
1 = PAIFRX_LRCLK determines oversampling rate, DACs 2/3
source PAIF Receiver
R16
3:0
PL[3:0]
1001
PL[3:0]
Left O/P
Mute
Right O/P
Mute
DAC
CONTROL
2
0000
0001
Left
Mute
0010
Right
(L+R)/2
Mute
Mute
10h
0011
Mute
0100
Left
0101
Left
Left
0110
Right
(L+R)/2
Mute
Left
0111
Left
1000
Right
Right
Right
Right
(L+R)/2
(L+R)/2
(L+R)/2
(L+R)/2
1001
Left
1010
Right
(L+R)/2
Mute
1011
1100
1101
Left
1110
Right
(L+R)/2
1111
6:4
DZFM[2:0]
000
Selects the– source for ZFLAG
000 -–All–DACs Zero Flag
001 -–DAC1 Zero Flag
010 -–DAC2 Zero Flag
011 -–DAC3 Zero Flag
100 -–DAC4 Zero F–ag
101 - ZFLAG – 0–110 - ZFLAG = 0
111 - ZFLAG = 0
7
IZD
0
Infinite zero detection circuit control and automute control
0 = Infinite zero detect automute disabled
1 = Infinite zero detect automute enabled
De-emphasis mode select
R17
3:0
DEEMP[3:0]
0000
DAC
CONTROL
3
DEEMP[0] = 1, enable De-emphasis on DAC1
DEEMP[1] = 1, enable De-emphasis on DAC2
DEEMP[2] = 1, enable De-emphasis on DAC3
DEEMP[3] = 1, enable De-emphasis on DAC 4
11h
4
DEEMPALL
0
0 = De-emphasis controlled by DEEMP[3:0]
1 = De-emphasis enabled on all DACs
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WM8581
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
Controls phase of DAC outputs
R18
7:0
PHASE [7:0]
11111111
DAC
CONTROL
4
0 = inverted
1 = non-inverted
PHASE[0] = 0 inverts phase of DAC1L output
PHASE[1] = 0 inverts phase of DAC1R output
PHASE[2] = 0 inverts phase of DAC2L output
PHASE[3] = 0 inverts phase of DAC2R output
PHASE[4] = 0 inverts phase of DAC3L output
PHASE[5] = 0 inverts phase of DAC3R output
PHASE[6] = 0 inverts phase of DAC4L output
PHASE[7] = 0 inverts phase of DAC4R output
DAC channel soft mute enables
12h
R19
3:0
DMUTE[3:0]
0000
DAC
CONTROL
5
DMUTE[0] = 1, enable soft-mute on DAC1
DMUTE[1] = 1, enable soft-mute on DAC2
DMUTE[2] = 1, enable soft-mute on DAC3
DMUTE[3] = 1, enable soft-mute on DAC4
13h
4
5
6
7
MUTEALL
DZCEN
0
0
0
0
DAC channel master soft mute. Mutes all DAC channels
0 = disable soft-mute on all DACs
1 = enable soft-mute on all DACs
DAC Digital Volume Zero Cross Enable
0 = Zero Cross detect disabled
1 = Zero Cross detect enabled
DACATC
MPDENB
Attenuator Control
0 = All DACs use attenuations as programmed.
1 = Right channel DACs use corresponding left DAC attenuations
MUTE pin decode enable
0 = MUTE activates soft-mute on DAC selected by DZFM
1 = MUTE activates softmute on all DACs
R20
7:0
8
LDA1[7:0]
UPDATE
11111111
(0dB)
Digital Attenuation control for DAC1 Left Channel (DACL1) in
0.5dB steps. See Table 23
DIGITAL
ATTENUATION
DACL 1
Not latched
Controls simultaneous update of all Attenuation Latches
0 = Store LDA1 in intermediate latch (no change to output)
1 = Apply LDA1 and update attenuation on all channels
14h
R21
7:0
8
RDA1[7:0]
UPDATE
11111111
(0dB)
Digital Attenuation control for DAC1 Right Channel (DACR1) in
0.5dB steps. See Table 23
DIGITAL
ATTENUATION
DACR 1
Not latched
Controls simultaneous update of all Attenuation Latches
0 = Store RDA1 in intermediate latch (no change to output)
1 = Apply RDA1 and update attenuation on all channels
15h
R22
7:0
8
LDA2[7:0]
UPDATE
11111111
(0dB)
Digital Attenuation control for DAC2 Left Channel (DACL2) in
0.5dB steps. See Table 23
DIGITAL
ATTENUATION
DACL 2
Not latched
Controls simultaneous update of all Attenuation Latches
0 = Store LDA2 in intermediate latch (no change to output)
1 = Apply LDA2 and update attenuation on all channels
16h
R23
7:0
8
RDA2[7:0]
UPDATE
11111111
(0dB)
Digital Attenuation control for DAC2 Right Channel (DACR2) in
0.5dB steps. See Table 23
DIGITAL
ATTENUATION
DACR 2
Not latched
Controls simultaneous update of all Attenuation Latches
0 = Store RDA2 in intermediate latch (no change to output)
1 = Apply RDA2 and update attenuation on all channels
17h
R24
7:0
8
LDA3[7:0]
UPDATE
11111111
(0dB)
Digital Attenuation control for DAC3 Left Channel (DACL3) in
0.5dB steps. See Table 23
DIGITAL
ATTENUATION
DACL 3
Not latched
Controls simultaneous update of all Attenuation Latches
0 = Store LDA3 in intermediate latch (no change to output)
1 = Apply LDA3 and update attenuation on all channels
18h
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Production Data
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
R25
7:0
RDA3[7:0]
11111111
(0dB)
Digital Attenuation control for DAC3 Right Channel (DACR3) in
0.5dB steps. See Table 23
DIGITAL
ATTENUATION
DACR 3
8
UPDATE
Not latched
Controls simultaneous update of all Attenuation Latches
0 = Store RDA3 in intermediate latch (no change to output)
1 = Apply RDA3 and update attenuation on all channels
19h
R26
7:0
8
LDA4[7:0]
UPDATE
11111111
(0dB)
Digital Attenuation control for DAC4 Left Channel (DACL4) in
0.5dB steps. See Table 23
DIGITAL
ATTENUATION
DACL 4
Not latched
Controls simultaneous update of all Attenuation Latches
0 = Store LDA4 in intermediate latch (no change to output)
1 = Apply LDA4 and update attenuation on all channels
1Ah
R27
7:0
8
RDA4[7:0]
UPDATE
11111111
(0dB)
Digital Attenuation control for DAC4 Right Channel (DACR4) in
0.5dB steps. See Table 23
DIGITAL
ATTENUATION
DACR 4
Not latched
Controls simultaneous update of all Attenuation Latches
0 = Store RDA4 in intermediate latch (no change to output)
1 = Apply RDA4 and update attenuation on all channels
1Bh
R28
7:0
8
MASTDA[7:0]
UPDATE
11111111
(0dB)
Digital Attenuation control for all DAC channels in 0.5dB steps.
See Table 23
MASTER
DIGITAL
Not latched
Controls simultaneous update of all Attenuation Latches
0 = Store gain in intermediate latch (no change to output)
1 = Apply gain and update attenuation on all channels
ADC Mute select
ATTENUATION
1Ch
R29
0
1
AMUTEL
AMUTER
0
0
ADC
CONTROL
1
0 : Normal Operation
1: mute ADC left
ADC Mute select
1Dh
0 : Normal Operation
1: mute ADC right
2
AMUTEALL
ADCOSR
0
ADC Mute select
0 : Normal Operation
1: mute both ADC channels
ADC oversample rate select
0 = 128/64 x oversampling
1 = 64/32 x oversampling
3
0
4
ADCHPD
0
ADC high-pass filter disable:
0 = high-pass filter enabled
1 = high-pass filter disabled
7:5
ADCRATE[2:0]
010
ADC Rate Control (only used when the S/PDIF Transmitter is the
only interface sourcing the ADC)
000 = 128fs
001 = 192fs
010 = 256fs
011 = 384fs
100 = 512fs
101 = 768fs
110 = 1152fs
8
VMIDSEL
1
VMID Impedance Selection
0 = High impedance, power saving
1 = Low impedance, fast power-on
S/PDIF Transmitter Data Source
00 = S/PDIF received data (see REAL_THROUGH)
01 = ADC digital output data.
R30
SPDTXCHAN 0
1Eh
1:0
TXSRC[1:0]
10
10 = Secondary Audio Interface
11 = Audio Interface received data
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WM8581
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
2
OVWCHAN
0
Only used if TXSRC==00. Overwrites the ‘through-path’ Channel
Bit with values determined by the channel-bit control registers.
0 = Channel data equal to recovered channel data.
1 = Channel data taken from channel status registers.
S/PDIF Through Mode Control
3
4
REAL_
0
0
THROUGH
0 = SPDIFOP pin sources output of S/PDIF Transmitter
1 = SPDIFOP pins sources output of S/PDIF IN Mux
S/PDIF Transmitter Validity Overwrite Mode
TXVAL_OVWR
0 = disabled, validity bit is 0 when transmitter sources ADC, PAIF
or SAIF, or is matches the S/PDIF input validity when S/PDIF
transmitter sources S/PDIF receiver.
1 = enabled, validity bit transmitted for subframe 0 is defined by
TXVAL_SF0, validity bit transmitted for subframe 1 is defined by
TXVAL_SF1.
5
6
TXVAL_SF0
TXVAL_SF1
0
0
Overwrite Mode S/PDIF Transmitter Validity Sub-Frame 0
0 = transmit validity = 0
1 = transmit validity = 1
Overwrite Mode S/PDIF Transmitter Validity Sub-Frame 1
0 = transmit validity = 0
1 = transmit validity = 1
R31
SPDTXCHAN 1
1Fh
0
1
CON/PRO
AUDIO_N
CPY_N
0
0
0 = Consumer Mode
1 = Professional Mode (not supported by WM8581)
0 = S/PDIF transmitted data is audio PCM.
1 = S/PDIF transmitted data is not audio PCM.
0 = Transmitted data has copyright asserted.
1 = Transmitted data has no copyright assertion.
000 = Data from Audio interface has no pre-emphasis.
001 = Data from Audio interface has pre-emphasis.
010 = Reserved (Audio interface has pre-emphasis).
011 = Reserved (Audio interface has pre-emphasis).
All other modes are reserved and should not be used.
00 = Only valid mode for consumer applications.
2
0
5:3
DEEMPH[2:0]
000
7:6
7:0
CHSTMODE
[1:0]
00
R32
SPDTXCHAN 2
20h
CATCODE
[7:0]
00000000
Category Code. Refer to S/PDIF specification for details.
00h indicates “general” mode
R33
3:0
5:4
SRCNUM
[3:0]
0000
00
Source Number. No definitions are attached to data.
SPDTXCHAN 3
21h
CHNUM1[1:0]
Channel Number for Subframe 1
CHNUM1
Channel Status Bits[21:20]
00
01
10
11
0000 = Do not use channel number
0001 = Send to Left Channel
0010 = Send to Right Channel
0000 = Do not use channel number
7:6
3:0
CHNUM2[1:0]
00
Channel Number for Subframe 2
CHNUM2
Channel Status Bits[23:22]
00
01
10
11
0000 = Do not use channel number
0001 = Send to Left Channel
0010 = Send to Right Channel
0000 = Do not use channel number
R34
FREQ[3:0]
0001
Sampling Frequency. See S/PDIF specification for details.
0001 = Sampling Frequency not indicated.
SPDTXCHAN 4
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Production Data
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
Clock Accuracy of Generated clock.
22h
5:4
CLKACU[1:0]
11
00 = Level II
01 = Level I
10 = Level III
11 = Interface frame rate not matched to sampling frequency.
Maximum Audio sample word length
0 = 20 bits
R35
SPDTXCHAN 5
23h
0
MAXWL
1
1 = 24 bits
3:1
TXWL[2:0]
101
Audio Sample Word Length.
000 = Word Length Not Indicated
TXWL[2:0]
MAXWL==1
MAXWL==
0
001
010
100
101
110
20 bits
22 bits
23 bits
24 bits
21 bits
16 bits
18 bits
19 bits
20 bits
17 bits
All other combinations reserved
7:4
0
ORGSAMP
[3:0]
0000
1
Original Sampling Frequency. See S/PDIF specification for details.
0000 = original sampling frequency not indicated
Selects the input circuit type for the SPDIFIN1 input
0 = CMOS-compatible input
R36
SPDMODE
24h
SPDIFIN1MODE
1 = Comparator input. Compatible with 500mVpp AC coupled
consumer S/PDIF input signals as defined in IEC-60958-3.
2:1
RXINSEL[1:0]
00
S/PDIF Receiver input mux select. Note that the general purpose
inputs must be configured using GPOxOP to be either CMOS or
comparator inputs if selected by RXINSEL.
00 = SPDIFIN1
01 = SPDIFIN2 (MFP3)
10 = SPDIFIN3 (MFP4)
11 = SPDIFIN4 (MFP5)
6
WL_MASK
MASK[8:0]
0
S/PDIF Receiver Word Length Truncation Mask
0 = disabled, data word is truncated as described in Table 60.
1 = enabled, data word is not truncated.
R37
INTMASK
25h
8:0
000000000
When a flag is masked, it does not update the Error Register or
contribute to the interrupt pulse.
0 = unmask, 1 = mask.
MASK[0] = mask control for UPD_UNLOCK
MASK[1] = mask control for INT_INVALID
MASK[2] = mask control for INT_CSUD
MASK[3] = mask control for INT_TRANS_ERR
MASK[4] = mask control for UPD_AUDIO_N
MASK[5] = mask control for UPD_PCM_N
MASK[6] = mask control for UPD_CPY_N
MASK[7] = mask control for UPD_DEEMPH
MASK[8] = mask control for UPD_REC_FREQ
0000 = INT_N
R38
3:0
GPO1OP[3:0]
0000
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WM8581
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
GPO1
26h
7:4
GPO2OP[3:0]
0001
0001 = V
0010 = U
0011 = C
0100 = P
0101 = SFRM_CLK
0110 = 192BLK
0111 = UNLOCK
1000 = CSUD
1001 = Invalid
1010 = ZFLAG
1011 = NON_AUDIO
1100 = CPY_N
1101 = DEEMP
1110 = Set GPO as S/PDIF input (standard CMOS input buffer).
Only applicable for GPO3/4/5.
1111 = Set GPO as S/PDIF input (‘comparator’ input for AC
coupled consumer S/PDIF signals). Only applicable for GPO3/4/5
8
FILLMODE
0
Fill Mode Overwrite Configuration
Determines S/PDIF receiver action when TRANS_ERR or
INVALID flag is masked and error condition sets the flag:
0 = Data from S/PDIF receiver is overwritten with last valid data
sample when flag is set.
1 = Data from S/PDIF receiver is overwritten as all zeros when flag
is set.
R39
GPO2
27h
3:0
7:4
GPO3OP[3:0]
GPO4OP[3:0]
0010
0011
0000 = INT_N
0001 = V
0010 = U
0011 = C
0100 = P
0101 = SFRM_CLK
0110 = 192BLK
0111 = UNLOCK
1000 = CSUD
1001 = Invalid
1010 = ZFLAG
1011 = NON_AUDIO
1100 = CPY_N
1101 = DEEMP
1110 = Set GPO as S/PDIF input (standard CMOS input buffer).
Only applicable for GPO3/4/5.
1111 = Set GPO as S/PDIF input (‘comparator’ input for AC
coupled consumer S/PDIF signals). Only applicable for GPO3/4/5
8
ALWAYSVALID
0
Automatic Error Handling Configuration for INVALID Flag
0 = INVALID flag automatic error handling enabled.
1 = INVALID flag automatic error handling disabled.
0000 = INT_N
R40
GPO3
28h
3:0
7:4
GPO5OP[3:0]
GPO6OP[3:0]
0100
0101
0001 = V
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Production Data
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
R41
GPO4
29h
3:0
GPO7OP[3:0]
0110
0010 = U
0011 = C
0100 = P
0101 = SFRM_CLK
0110 = 192BLK
0111 = UNLOCK
1000 = CSUD
1001 = Invalid
1010 = ZFLAG
1011 = NON_AUDIO
1100 = CPY_N
1101 = DEEMP
1110 = Set GPO as S/PDIF input (standard CMOS input buffer).
Only applicable for GPO3/4/5.
1111 = Set GPO as S/PDIF input (‘comparator’ input for AC
coupled consumer S/PDIF signals). Only applicable for GPO3/4/5
R43
INTSTAT
2Bh
0
1
2
3
4
5
6
7
0
UPD_UNLOCK
INT_INVALID
INT_CSUD
-
-
-
-
-
-
-
-
-
UNLOCK flag update signal
0 = INT_N not caused by update to UNLOCK flag
1 = INT_N caused by update to UNLOCK flag
INVALID flag interrupt signal
0 = INT_N not caused by INVALID flag
1 = INT_N caused by INVALID flag
CSUD flag interrupt signal
0 = INT_N not caused by CSUD flag
1 = INT_N caused by CSUD flag
INT_TRANS_ERR
UPD_NON_AUDIO
UPD_CPY_N
UPD_DEEMPH
UPD_REC_FREQ
CON/PRO
TRANS_ERR flag interrupt signal
0 = INT_N not caused by TRANS_ERR flag
1 = INT_N caused by TRANS_ERR flag
NON_AUDIO update signal
0 = INT_N not caused by update to NON_AUDIO flag
1 = INT_N caused by update to NON_AUDIO flag
CPY_N update signal
0 = INT_N not caused by update to CPY_N flag
1 = INT_N caused by update to CPY_N flag
DEEMPH update signal
0 = INT_N not caused by update to DEEMPH flag
1 = INT_N caused by update to DEEMPH flag
REC_FREQ update signal
0 = INT_N not caused by update to REC_FREQ flag
1 = INT_N caused by update to REC_FREQ flag
0 = Consumer Mode
R44
SPDRXCHAN 1
2C
1 = Professional Mode
The WM8581 is a consumer mode device. Detection of
professional mode may give erroneous behaviour.
1
AUDIO_N
-
Recovered S/PDIF Channel status bit 1.
0 = Data word represents audio PCM samples.
1 = Data word does not represent audio PCM samples.
0 = Copyright is asserted for this data.
2
3
CPY_N
DEEMPH
Reserved
-
-
-
1 = Copyright is not asserted for this data.
0 = Recovered S/PDIF data has no pre-emphasis.
1 = Recovered S/PDIF data has pre-emphasis.
Reserved for additional de-emphasis modes.
5:4
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WM8581
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
7:6
CHSTMODE
[1:0]
-
00 = Only valid mode for consumer applications.
R45
SPDRXCHAN 2
2Dh
7:0
CATCODE
[7:0]
-
Category Code. Refer to S/PDIF specification for details.
00h indicates “general” mode.
R46
3:0
5:4
SRCNUM
[3:0]
-
-
Indicates number of S/PDIF source.
Channel number for sub-frame 1.
SPDRXCHAN 3
2Eh
CHNUM1[1:0]
00 = Take no account of channel number (channel 1 defaults to
left DAC)
01 = channel 1 to left channel
10 = channel 1 to right channel
Channel number for sub-frame 2.
7:6
CHNUM2[1:0]
00 = Take no account of channel number (channel 2 defaults to
left DAC)
01 = channel 2 to left channel
10 = channel 2 to right channel
Sampling Frequency. See S/PDIF specification for details.
0001 = Sampling Frequency not indicated.
Clock Accuracy of received clock.
00 = Level II
R47
SPDRXCHAN 4
2Fh
3:0
5:4
FREQ[3:0]
-
-
CLKACU[1:0]
01 = Level I
10 = Level III
11 = Interface frame rate not matched to sampling frequency.
R48
SPDRXCHAN 5
30h
0
MAXWL
-
-
Maximum Audio sample word length
0 = 20 bits
1 = 24 bits
3:1
RXWL[2:0]
Audio Sample Word Length.
000: Word Length Not Indicated
RXWL[2:0]
MAXWL==1
MAXWL==
0
001
010
100
101
110
20 bits
22 bits
23 bits
24 bits
21 bits
16 bits
18 bits
19 bits
20 bits
17 bits
All other combinations are reserved and may give erroneous
operation. Data will be truncated internally when these bits are set
unless WL_MASK is set.
7:4
0
ORGSAMP
[3:0]
-
-
-
Original Sampling Frequency. See S/PDIF specification for details.
0000 = original sampling frequency not indicated
R49
SPDSTAT
31h
AUDIO_N
PCM_N
Recovered Channel Status bit-1.
0 = Data word represents audio PCM samples.
1 = Data word does not represent audio PCM samples.
1
Indicates that non-audio code (defined in IEC-61937) has been
detected.
0 = Sync code not detected.
1 = Sync code detected – received data is not audio PCM.
Recovered Channel Status bit-2.
2
CPY_N
-
0 = Copyright is asserted for this data.
1 = Copyright is not asserted for this data.
Note this signal is inverted and will cause an interrupt on logic 0.
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REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
Recovered Channel Status bit-3
3
DEEMPH
-
0 = Recovered S/PDIF data has no pre-emphasis.
1 = Recovered S/PDIF data has pre-emphasis
Indicates recovered S/PDIF clock frequency:
00 = Invalid
5:4
REC_FREQ
[1:0]
--
01 = 96kHz / 88.2kHz
10 = 48kHz / 44.1kHz
11 = 32kHz
6
0
UNLOCK
PWDN
-
Indicates that the S/PDIF Clock Recovery circuit is unlocked or
that the input S/PDIF signal is not present.
0 = Locked onto incoming S/PDIF stream.
1 = Not locked to the incoming S/PDIF stream or the incoming
S/PDIF stream is not present.
R50
PWRDN 1
32h
0
Chip Powerdown Control (works in tandem with the other
powerdown registers):
0 = All digital circuits running, outputs are active
1 = All digital circuits in power save mode, outputs muted
ADC powerdown:
1
ADCPD
1
0 = ADC enabled
1 = ADC disabled
5:2
DACPD[3:0]
1111
DAC powerdowns (0 = DAC enabled, 1 = DAC disabled)
DACPD[0] = DAC1
DACPD[1] = DAC2
DACPD[2] = DAC3
DACPD[3] = DAC4
6
0
ALLDACPD
OSCPD
1
0
Overrides DACPD[3:0]
0 = DACs under control of DACPD[3:0]
1= All DACs are disabled.
OSC power down
R51
PWRDN 2
33h
0 = OSC enabled
1 = OSC disabled
1
2
3
PLLAPD
PLLBPD
SPDIFPD
1
1
1
0 = PLLA enabled
1 = PLLA disabled
0 = PLLB enable
1 = PLLB disable
S/PDIF Clock Recovery PowerDown
0 = S/PDIF enabled
1 = S/PDIF disabled
4
5
SPDIFTXD
SPDIFRXD
1
1
S/PDIF Transmitter powerdown
0 = S/PDIF Transmitter enabled
1 = S/PDIF Transmitter disabled
S/PDIF Receiver powerdown
0 = S/PDIF Receiver enabled
1 = S/PDIF Receiver disabled
Determines which status register is to be read back:
000 = Error Register
R52
READBACK
34h
2:0
READMUX
[2:0]
000
001 = Channel Status Register 1
010 = Channel Status Register 2
011 = Channel Status Register 3
100 = Channel Status Register 4
101 = Channel Status Register 5
110 = S/PDIF Status Register
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WM8581
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
Continuous Read Enable.
3
CONTREAD
0
0 = Continuous read-back mode disabled
1 = Continuous read-back mode enabled
Read-back mode enable.
4
READEN
RESET
0
0 = read-back mode disabled
1 = read-back mode enabled
R53
RESET
35h
8:0
n/a
Writing to this register will apply a reset to the device registers.
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DIGITAL FILTER CHARACTERISTICS
PARAMETER
TEST CONDITIONS
ADC Filter
MIN
TYP
MAX
0.4535fs
0.01
UNIT
Passband
0.01 dB
-6dB
0
0.5fs
Passband ripple
Stopband
dB
dB
0.5465fs
-65
Stopband Attenuation
f > 0.5465fs
DAC Filter
Passband
0.05 dB
-3dB
0.444fs
0.05
0.487fs
Passband ripple
Stopband
dB
dB
0.555fs
-60
Stopband Attenuation
f > 0.555fs
Table 76 Digital Filter Characteristics
DAC FILTER RESPONSES
0.2
0
0.15
0.1
-20
-40
0.05
0
-60
-0.05
-0.1
-0.15
-0.2
-80
-100
-120
0
0.5
1
1.5
2
2.5
3
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
0.5
Frequency (Fs)
Frequency (Fs)
Figure 37 DAC Digital Filter Frequency Response
– 44.1, 48 and 96KHz
Figure 38 DAC Digital Filter Ripple –44.1, 48 and 96kHz
0.2
0
0
-20
-40
-60
-80
-0.2
-0.4
-0.6
-0.8
-1
0
0.2
0.4
0.6
0.8
1
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
0.5
Frequency (Fs)
Frequency (Fs)
Figure 39 DAC Digital Filter Frequency Response
– 192KHz
Figure 40 DAC Digital Filter Ripple – 192kHz
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WM8581
DIGITAL DE-EMPHASIS CHARACTERISTICS
0
-2
0.4
0.3
0.2
0.1
0
-4
-6
-0.1
-0.2
-0.3
-0.4
-8
-10
0
5
10
15
20
0
5
10
15
20
Frequency (kHz)
Frequency (kHz)
Figure 41 De-Emphasis Frequency Response (44.1KHz)
Figure 42 De-Emphasis Error (44.1KHz)
0
1
0.8
0.6
0.4
0.2
0
-2
-4
-6
-0.2
-0.4
-0.6
-0.8
-1
-8
-10
0
5
10
15
20
0
5
10
15
20
Frequency (kHz)
Frequency (kHz)
Figure 43 De-Emphasis Frequency Response (48kHz)
Figure 44 De-Emphasis Error (48kHz)
ADC FILTER RESPONSES
0.02
0.015
0.01
0
-20
-40
-60
-80
0.005
0
-0.005
-0.01
-0.015
-0.02
0
0.5
1
1.5
2
2.5
3
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
0.5
Frequency (Fs)
Frequency (Fs)
Figure 45 ADC Digital Filter Frequency Response
Figure 46 ADC Digital Filter Ripple
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ADC HIGH PASS FILTER
The WM8581 has a selectable digital high pass filter to remove DC offsets. The filter response is characterised by the following
polynomial.
1 - z-1
H(z) =
1 - 0.9995z-1
0
-5
-10
-15
0
0.0005
0.001
Frequency (Fs)
0.0015
0.002
Figure 47 ADC Highpass Filter Response
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WM8581
APPLICATIONS INFORMATION
RECOMMENDED EXTERNAL COMPONENTS
Figure 48 Recommended–External Components - Hardware
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Figure 49 Recommended–External Components - Software
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WM8581
PACKAGE DIMENSIONS
FT: 48 PIN TQFP (7 x 7 x 1.0 mm)
DM004.C
b
e
36
25
37
24
E1
E
48
13
1
12
Θ
D1
D
c
L
A1
A
A2
-C-
SEATING PLANE
ccc
C
Dimensions
(mm)
Symbols
MIN
-----
0.05
0.95
0.17
0.09
NOM
-----
-----
1.00
0.22
-----
MAX
1.20
0.15
1.05
0.27
0.20
A
A1
A2
b
c
D
D1
E
E1
e
L
Θ
9.00 BSC
7.00 BSC
9.00 BSC
7.00 BSC
0.50 BSC
0.60
0.45
0o
0.75
7o
3.5o
Tolerances of Form and Position
0.08
ccc
REF:
JEDEC.95, MS-026
NOTES:
A. ALL LINEAR DIMENSIONS ARE IN MILLIMETERS.
B. THIS DRAWING IS SUBJECT TO CHANGE WITHOUT NOTICE.
C. BODY DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSION, NOT TO EXCEED 0.25MM.
D. MEETS JEDEC.95 MS-026, VARIATION = ABC. REFER TO THIS SPECIFICATION FOR FURTHER DETAILS.
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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
Westfield House
26 Westfield Road
Edinburgh
EH11 2QB
United Kingdom
Tel :: +44 (0)131 272 7000
Fax :: +44 (0)131 272 7001
Email :: sales@wolfsonmicro.com
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