WM8581 Product Datasheet

WM8581
w
Multichannel CODEC with S/PDIF Transceiver
DESCRIPTION
FEATURES
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.
•
•
•
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.
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.
The device has two PLLs which can be configured
independently to generate two system clocks for internal or
external use.
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.
Audio Performance
−
−
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.
Also included are four stereo 24-bit multi-bit sigma delta
DACs, each with a dedicated oversampling digital
interpolation filter. Digital audio input word lengths from 16bits to 32-bits and sampling rates from 8kHz to 192kHz are
supported. Each DAC channel has independent digital
volume and mute control.
Multi-channel CODEC with 4 Stereo DACs and 1 Stereo
ADC
Integrated S/PDIF / IEC-60958-3 transceiver
•
103dB SNR (‘A’ weighted @ 48kHz) DAC
-90dB THD (48kHz) DAC
−
100dB SNR (‘A’ weighted @ 48kHz) ADC
−
-87dB THD (48kHz) ADC
DAC Sampling Frequency: 8kHz – 192kHz
•
•
•
ADC Sampling Frequency: 8kHz – 192kHz
Independent ADC and DAC Sample Rates
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
−
•
•
•
•
•
I2S, Left, Right Justified or DSP
−
16/20/24/32 bit Word Lengths
Four independent stereo DAC outputs with independent
digital volume controls
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
48-lead TQFP Package
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
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Production Data, March 2009, Rev 4.7
Copyright ©2009 Wolfson Microelectronics plc
WM8581
Production Data
BLOCK DIAGRAM
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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 .......................................................................................... 8
ELECTRICAL CHARACTERISTICS............................................................................................................ 9
TERMINOLOGY...................................................................................................................................................... 11
MASTER CLOCK TIMING ...................................................................................................................................... 12
DIGITAL AUDIO INTERFACE – MASTER MODE .................................................................................................. 13
DIGITAL AUDIO INTERFACE – SLAVE MODE ..................................................................................................... 14
CONTROL INTERFACE TIMING – 3-WIRE MODE ............................................................................................... 15
CONTROL INTERFACE TIMING – 2-WIRE MODE ............................................................................................... 15
DEVICE DESCRIPTION............................................................................................................................. 17
INTRODUCTION..................................................................................................................................................... 17
CONTROL INTERFACE OPERATION ................................................................................................................... 18
DIGITAL AUDIO INTERFACES .............................................................................................................................. 22
AUDIO DATA FORMATS........................................................................................................................................ 24
AUDIO INTERFACE CONTROL ............................................................................................................................. 28
DAC FEATURES .................................................................................................................................................... 30
ADC FEATURES .................................................................................................................................................... 37
DIGITAL ROUTING OPTIONS................................................................................................................................ 38
CLOCK SELECTION .............................................................................................................................................. 40
PHASE-LOCKED LOOPS AND S/PDIF CLOCKING (SOFTWARE MODE) .......................................................... 51
PHASE-LOCKED LOOPS AND S/PDIF CLOCKING (HARDWARE MODE).......................................................... 59
S/PDIF TRANSCEIVER.......................................................................................................................................... 59
S/PDIF TRANSMITTER .......................................................................................................................................... 60
S/PDIF RECEIVER ................................................................................................................................................. 63
POWERDOWN MODES......................................................................................................................................... 72
INTERNAL POWER ON RESET CIRCUIT............................................................................................................. 74
HARDWARE CONTROL MODE............................................................................................................................. 76
REGISTER MAP ........................................................................................................................................ 79
DIGITAL FILTER CHARACTERISTICS .................................................................................................... 95
DAC FILTER RESPONSES.................................................................................................................................... 95
DIGITAL DE-EMPHASIS CHARACTERISTICS...................................................................................................... 96
ADC FILTER RESPONSES.................................................................................................................................... 96
ADC HIGH PASS FILTER....................................................................................................................................... 97
APPLICATIONS INFORMATION............................................................................................................... 98
RECOMMENDED EXTERNAL COMPONENTS ..................................................................................................... 98
PACKAGE DIMENSIONS ........................................................................................................................ 100
IMPORTANT NOTICE.............................................................................................................................. 101
ADDRESS:............................................................................................................................................................ 101
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PIN CONFIGURATION
ORDERING INFORMATION
DEVICE
TEMPERATURE
RANGE
PACKAGE
MOISTURE
SENSITIVITY LEVEL
PEAK
SOLDERING
TEMPERATURE
WM8581AGEFT/V
-40 to +85oC
48-lead TQFP
(Pb-free)
MSL2
260°C
WM8581AGEFT/RV
-40 to +85oC
48-lead TQFP
(Pb-free, tape and reel)
MSL2
260°C
Note:
Reel quantity = 2,200
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PIN DESCRIPTION
PIN
NAME
TYPE
1
VOUT4L
Analogue Output
DESCRIPTION
2
VOUT4R
Analogue Output
3
PGND
Supply
4
PVDD
Supply
5
XTI
Digital Input
6
XTO
Digital Output
7
MFP7
Digital Input/Output
Multi-Function Pin (MFP) 7. See Table 1 for details of all MFP pins.
8
MFP6
Digital Input/Output
Multi-Function Pin (MFP) 6. See Table 1 for details of all MFP pins.
9
SPDIFOP
Digital Output
10
MFP5
Digital Input/Output
Multi-Function Pin (MFP) 5. See Table 1 for details of all MFP pins.
11
MFP4
Digital Input/Output
Multi-Function Pin (MFP) 4. See Table 1 for details of all MFP pins.
12
MFP3
Digital Input/Output
Multi-Function Pin (MFP) 3. See Table 1 for details of all MFP pins.
13
SPDIFIN1
Digital Input
14
CLKOUT
Digital Output
15
DVDD
Supply
Digital positive supply
16
DGND
Supply
Digital ground
17
MUTE
Digital Input/Output
18
DIN1
Digital Input
Primary Audio Interface (PAIF) receiver data input 1
19
DIN2
Digital Input
Primary Audio Interface (PAIF) receiver data input 2
20
DIN3
Digital Input
Primary Audio Interface (PAIF) receiver data input 3
21
DIN4
Digital Input
Primary Audio Interface (PAIF) receiver data input 4
22
PAIFRX_LRCLK
Digital Input/Output
Primary Audio Interface (PAIF) receiver left/right word clock
23
PAIFRX_BCLK
Digital Input/Output
Primary Audio Interface (PAIF) receiver bit clock
24
MCLK
Digital Input/Output
25
DOUT
Digital Output
26
PAIFTX_LRCLK
Digital Input/Output
Primary audio interface transmitter left/right word clock
27
MFP1
Digital Input/Output
Multi-Function Pin (MFP) 1. See Table 1 for details of all MFP pins.
28
MFP2
Digital Input/Output
Multi-Function Pin (MFP) 2. See Table 1 for details of all MFP pins.
29
HWMODE
Digital Input
30
SWMODE
Digital Input/Output
31
SDO
Digital Output
32
SDIN
Digital Input/Output
33
SCLK
Digital Input
Control interface clock
3-wire control interface latch signal / device address selection
DAC channel 4 left output
DAC channel 4 right output
PLL ground
PLL positive supply
Crystal or CMOS clock input
Crystal output
S/PDIF transmitter output
S/PDIF Receiver Input 1
PLL or crystal oscillator clock output
DAC mute-all input/ All-DAC Infinite Zero Detect (IZD) flag output
System Master clock; 256, 384, 512, 768, 1024 or 1152 fs
Primary Audio Interface (PAIF) transmitter data output
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)
34
CSB
Digital Input
35
AINR
Analogue Input
ADC Right Channel Input
36
AINL
Analogue Input
ADC Left Channel Input
37
ADCREFP
Analogue Output
ADC reference buffer decoupling pin; 10uF external decoupling
38
VMID
Analogue Output
Midrail divider decoupling pin; 10uF external decoupling
39
AGND
Supply
Analogue ground
40
AVDD
Supply
Analogue positive supply
41
VOUT1L
Analogue Output
DAC channel 1 left output
42
VOUT1R
Analogue Output
DAC channel 1 right output
43
VOUT2L
Analogue Output
DAC channel 2 left output
44
VOUT2R
Analogue Output
DAC channel 2 right output
45
VREFP
Analogue Input
DAC and ADC positive reference
46
VREFN
Analogue Input
DAC and ADC ground reference
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PIN
NAME
TYPE
47
VOUT3L
Analogue Output
DAC channel 3 left output
DESCRIPTION
48
VOUT3R
Analogue Output
DAC channel 3 right output
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.
Y
HWMODE = 1
N
Y
SAIF_EN = 1
N
GPIOnOP
PIN NAME
HARDWARE
CONTROL MODE
FUNCTION
1
SECONDARY AUDIO
INTERFACE FUNCTION
2
S/PDIF INPUT &
INDEPENDENT
CLOCKING
3
GENERAL PURPOSE
OUTPUT FUNCTION
4
MFP1
PAIFTX_BCLK
n/a1
PAIFTX_BCLK2
GPO1
1
MFP2
ADCMCLK
n/a
ADCMCLK3
GPO2
MFP3
DR1
n/a1
SPDIFIN2
GPO3
MFP4
DR2
SAIF_DIN
SPDIFIN3
GPO4
MFP5
DR3
SAIF_DOUT
SPDIFIN4
GPO5
MFP6
DR4
SAIF_BCLK
GPO6
GPO6
MFP7
ALLPD
SAIF_LRCLK
GPO7
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 usage can be described as follows:
IF (ADC_CLKSEL = MCLK) AND (PAIFTXMS_CLKSEL = MCLK) THEN
MFP1 = GPO1;
ELSE
MFP1 = PAIFTX_BCLK ; (default)
Notes for MFP1:
ADC_CLKSEL selected in REG 8, default is ADC_MCLK.
PAIFTXMS_CLKSEL selects PLLACLK if PAIF sources SPDIF Rx, otherwise PAIFTXMS_CLKSEL selects ADC_CLK
(register 8)
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3.
MFP2 usage can be described as follows:
IF
(ADC_CLKSEL ≠ ADCMCLK)
AND
(TX_CLKSEL ≠ ADCMCLK)
(controlled by reg 8)
(controlled by reg 8)
AND
(SAIFMS_CLKSEL ≠ ADCMCLK) THEN
(controlled by reg 8)
MFP2 = GPO2;
ELSE
MFP2 = ADCMCLK;
PIN FUNCTION
TYPE
DESCRIPTION
PAIFTX_BCLK
Digital Input/Output
Primary Audio Interface Transmitter (PAIFTX) Bit Clock
ADCMCLK
Digital Input
Master ADC clock; 256fs, 384fs, 512fs ,786fs, 1024fs or 1152fs
SAIF_DIN
Digital Input
Secondary Audio Interface (SAIF) Receiver data input
SAIF_DOUT
Digital Output
Secondary Audio Interface (SAIF) Transmitter data output
SAIF_BCLK
Digital Input/Output
Secondary Audio Interface (SAIF) Bit Clock
SAIF_LRCLK
Digital Input/Output
Secondary Audio Interface (SAIF) Left/Right Word Clock
SPDIFIN2/3/4
Digital Input
S/PDIF Receiver Input
GPO1 - GPO7
Digital Output
General Purpose Output
DR1/2/3/4
Digital Input
Internal Digital Routing Configuration in Hardware Mode
ALLPD
Digital Input
Chip Powerdown in Hardware Mode
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.
MIN
MAX
Digital supply voltage
CONDITION
-0.3V
+3.63V
Analogue supply voltage
-0.3V
+7V
PLL supply voltage
-0.3V
+5.5V
Voltage range digital inputs (SCLK, CSB & SDIN only)
DGND -0.3V
+7V
Voltage range digital inputs
DGND -0.3V
DVDD + 0.3V
AGND -0.3V
PGND -0.3V
AVDD +0.3V
PVDD +0.3V
Voltage range analogue inputs
1
Master Clock Frequency
37MHz
Operating temperature range, TA
-40°C
Storage temperature prior to soldering
+85°C
30°C max / 85% RH max
Storage temperature after soldering
-65°C
+150°C
Pb Free Package body temperature (soldering 10 seconds)
+260°C
Package body temperature (soldering 2 minutes)
+183°C
Notes: 1. Analogue and digital grounds must always be within 0.3V of each other.
RECOMMENDED OPERATING CONDITIONS
PARAMETER
MAX
UNIT
Digital supply range
DVDD
2.7
3.6
V
Analogue supply range
AVDD
2.7
5.5
V
PLL supply range
PVDD
4.5
5.5
V
Ground
SYMBOL
TEST CONDITIONS
MIN
AGND, VREFN, DGND.
PGND
Difference DGND to
AGND/PGND
TYP
0
-0.3
0
V
+0.3
V
Note: Digital supply DVDD must never be more than 0.3V greater than AVDD.
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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
DAC Performance (Load = 10kΩ, 50pF) (+25˚C)
0dBFs Full scale output voltage
Signal to Noise Ratio (See
Terminology note 1,2,4)
SNR
1.0 x
VREFP/5
Vrms
103
dB
Unweighted,
@ fs = 48kHz
100
dB
A-Weighted
@ fs = 48kHz, AVDD =
3.3V
99
dB
A-Weighted
@ fs = 96kHz
101
dB
Unweighted,
@ fs = 96kHz
98
dB
A-Weighted
@ fs = 96kHz, AVDD =
3.3V
99
dB
A-Weighted
@ fs = 192kHz
101
dB
Unweighted,
@ fs = 192kHz
98
dB
A-Weighted
@ fs = 192kHz, AVDD
= 3.3V
99
dB
103
dB
A-Weighted
@ fs = 48kHz
95
Dynamic Range (See
Terminology note 2,4)
DNR
A-weighted, -60dB full
scale input
Total Harmonic Distortion
THD
1kHz, 0dB Full Scale @
fs = 48kHz
-90
1kHz, 0dB Full Scale @
fs = 96kHz
-87
dB
1kHz, 0dB Full Scale @
fs = 192kHz
-84
dB
100
dB
1kHz Input, 0dB gain
100
dB
2
mV
1kHz 100mVp-p
50
dB
20Hz to 20kHz
100mVp-p
45
dB
1.0 x
VREFP/5
Vrms
Input resistance
6
kΩ
Input capacitance
10
pF
100
dB
Unweighted,
@ fs = 48kHz
97
dB
A-Weighted
@ fs = 48kHz, AVDD =
3.3V
97
dB
95
DAC Channel separation
Mute Attenuation
Output Offset Error
Power Supply Rejection Ratio
(See note 4)
PSRR
-85
dB
ADC Performance (+25˚C)
Full Scale Input Signal Level (for
ADC 0dB Input)
Signal to Noise Ratio (See
Terminology note 1,2,4)
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SNR
A-Weighted
@ fs = 48kHz
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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
Total Harmonic Distortion
Dynamic Range
THD
DNR
ADC Channel Separation
TEST CONDITIONS
MIN
TYP
MAX
UNIT
A-Weighted
@ fs = 96kHz
97
dB
Unweighted,
@ fs = 96kHz
94
dB
A-Weighted
@ fs = 96kHz, AVDD =
3.3V
94
dB
A-Weighted
@ fs = 192kHz
97
dB
Unweighted,
@ fs = 192kHz
94
dB
A-Weighted
@ fs = 192kHz, AVDD
= 3.3V
94
dB
1kHz, -1dB Full Scale
@ fs = 48kHz
-87
1kHz, -1dB Full Scale
@ fs = 96kHz
-86
dB
1kHz, -1dB Full Scale
@ fs = 192kHz
-85
dB
-60dB FS
90
-80
dB
100
1kHz Input
97
dB
Channel Level Matching (See
Terminology note 4)
1KHz Signal
0.1
dB
Channel Phase Deviation
1kHz Signal
0.0001
Degree
HPF On
HPF Off
0
100
LSB
LSB
Offset Error
Digital Logic Levels (CMOS Levels)
Input LOW level
VIL
Input HIGH level
VIH
0.3 x DVDD
0.7 x DVDD
Input leakage current
-1
Input capacitance
±0.2
+1
5
Output LOW
VOL
IOL=1mA
Output HIGH
VOH
IOH= -1mA
V
V
µA
pF
0.1 x DVDD
0.9 x DVDD
V
V
Analogue Reference Levels
Reference voltage
VVMID
Potential divider resistance
RVMID
VREFP/2 –
50mV
VREFP/2
VREFP/2 +
50mV
V
VREFP to VMID and
VMID to VREFN
VMIDSEL = 1
14
kΩ
VREFP to VMID and
VMID to VREFN
VMIDSEL = 0
44
kΩ
50
ps
S/PDIF Transceiver Performance
Jitter on recovered clock
S/PDIF Input Levels CMOS MODE
Input LOW level
VIL
Input HIGH level
VIH
Input capacitance
0.3 X DVDD
0.7 X DVDD
V
V
1.25
Input Frequency
pF
36
MHz
S/PDIF Input Levels Comparator MODE
Input capacitance
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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
Input resistance
TYP
MAX
UNIT
25
MHz
0.5 X DVDD
mV
23
kΩ
Input frequency
Input Amplitude
200
PLL
Period Jitter
80
ps(rms)
XTAL
Input XTI LOW level
VXIL
0
Input XTI HIGH level
VXIH
853
Input XTI capacitance
CXJ
3.32
4.491
pF
IXleak
28.92
38.96
mA
Input XTI leakage
557
mV
mV
Output XTO LOW
VXOL
15pF load capacitors
86
278
mV
Output XTO HIGH
VXOH
15pF load capacitors
1.458
1.942
V
Supply Current
Analogue supply current
AVDD, VREFP = 5V
45
mA
Analogue supply current
AVDD, VREFP = 3.3V
30
mA
25
mA
500
µA
Digital supply current
DVDD = 3.3V
Power Down
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
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.
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MASTER CLOCK TIMING
t MCLKL
ADCMCLK/
MCLK
t MCLKH
t MCLKY
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
11
ns
ADCMCLK and MCLK System clock
pulse width low
tMCLKL
11
ns
ADCMCLK and MCLK System clock
cycle time
tMCLKY
28
ns
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/
SAIF_LRCLK propagation
delay from PAIFTX_BCLK/
PAIFRX_BCLK/
SAIF_BCLK falling edge
tDL
0
10
ns
DOUT/SAIF_DOUT
propagation delay from
PAIFTX_BCLK/
SAIF_BCLK falling edge
tDDA
0
10
ns
DIN1/2/3/4/SAIF_DIN setup
time to
PAIFRX_BCLK/SAIF_BCLK
rising edge
tDST
10
ns
DIN1/2/3/4/SAIF_DIN hold
time from
PAIFRX_BCLK/SAIF_BCLK
rising edge
tDHT
10
ns
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/
PAIFRX_BCLK/SAIF_BCLK cycle
time
tBCY
50
ns
PAIFTX_BCLK/
PAIFRX_BCLK/SAIF_BCLK pulse
width high
tBCH
20
ns
PAIFTX_BCLK/
PAIFRX_BCLK/SAIF_BCLK pulse
width low
tBCL
20
ns
PAIFTX_LRCLK/
PAIFRX_LRCLK/SAIF_BCLK set-up
time to PAIFTX_BCLK/
PAIFRX_BCLK/SAIF_BCLK rising
edge
tLRSU
10
ns
PAIFTX_LRCLK/
PAIFRX_LRCLK/
SAIF_LRCLK hold time from
PAIFTX_BCLK/
PAIFRX_BCLK/SAIF_BCLK rising
edge
tLRH
10
ns
DIN1/2/3/4/SAIF_DIN set-up time to
PAIFRX_BCLK/
SAIF_BCLK rising edge
tDS
10
ns
DIN1/2/3/4/SAIF_DIN hold time
from PAIFRX_BCLK/SAIF_BCLK
rising edge
tDH
10
ns
DOUT/SAIF_DOUT propagation
delay from
PAIFTX_BCLK/SAIF_BCLK falling
edge
tDD
0
10
ns
Table 5 Digital Audio Data Timing – Slave Mode
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CONTROL INTERFACE TIMING – 3-WIRE MODE
t CSS
tCSM
t CSH
CSB
t SCY
t CSU
t SCS
SCLK
LSB
SDIN
t DSU
t DHO
LSB
SDO
t DL
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
SYMBOL
MIN
SCLK rising edge to CSB rising edge
PARAMETER
tSCS
60
ns
SCLK pulse cycle time
tSCY
80
ns
SCLK duty cycle
TYP
40/60
SDIN to SCLK set-up time
tDSU
20
SDIN hold time from SCLK rising edge
tDHO
20
MAX
UNIT
60/40
ns
ns
ns
SDO propagation delay from SCLK falling
edge
tDL
CSB pulse width high
tCSH
20
ns
SCLK to CSB low (required for read cycle)
set-up time
tCSU
20
ns
CSB min (write cycle only)
tCSM
0.5* tSCY
ns
CSB rising/falling to SCLK rising
tCSS
20
ns
tps
2
SCLK glitch suppression
5
ns
8
ns
Table 6 3-wire SPI Compatible Control Interface Input Timing Information
CONTROL INTERFACE TIMING – 2-WIRE MODE
t
t
t
3
5
3
SDIN
t
t
t
6
2
4
t
8
SCLK
t
1
t
9
t
7
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
SCLK Low Pulse-Width
t1
1.3
526
kHz
us
SCLK High Pulse-Width
t2
600
ns
Hold Time (Start Condition)
t3
600
ns
Setup Time (Start Condition)
t4
600
ns
Data Setup Time
t5
100
SDIN, SCLK Rise Time
t6
300
SDIN, SCLK Fall Time
t7
300
Setup Time (Stop Condition)
t8
Program Register Input Information
SCLK Frequency
0
Data Hold Time
t9
SCLK glitch suppression
tps
ns
600
0
ns
ns
ns
900
ns
5
ns
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
76.
Software control is implemented with a 3-wire (3-wire write, 4-wire read, SPI compatible) or 2-wire (2wire 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
0
Software Control
SWMODE
1
Hardware Control
0
2-wire control
1
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
REGISTER WRITE
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. The CSB can be low for the duration of the write cycle or it can be a short CSB
pulse at the end of the write cycle.
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
Not all registers can be read. Only the device ID (registers R0, R1 and R2) and the status registers
can be read. These status registers are labelled as “read only” in the Register Map section.
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.
Each time a read operation is performed after any write operation, the first read result may contain
corrupt data. To ensure correct operation, the first read result should be ignored and a second read
operation carried out. Subsequent register reads are unaffected until further register writes are
performed
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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
REGISTER ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
R52
READBACK
34h
2:0
READMUX
[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
3
CONTREAD
0
Continuous Read Enable.
0 = Continuous read-back mode
disabled
1 = Continuous read-back mode
enabled
4
READEN
0
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.
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Figure 8 3-Wire SPI Compatible Control Interface Non-Continuous Readback
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 2WIRE MODE
ADDRESS (X=R/W BIT)
X=0
X= 1
Low or Unconnected
0011010x
0x34
0x35
High
0011011x
0x36
0x37
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
R9
5
PAIFRX
MS
0
PAIF Rx Master/Slave Mode Select:
0 = Slave Mode
1 = Master Mode
5
PAIFTX
MS
0
PAIF Tx Master/Slave Mode Select:
0 = Slave Mode
1 = Master Mode
5
SAIFMS
0
SAIF Master/Slave Mode Select:
0 = Slave Mode
1 = Master Mode
R10
R11
DESCRIPTION
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
(LRCLK)
MCLK CLOCK FREQUENCY (MHZ)
128fs
192fs
256fs
384fs
512fs
768fs
1152fs
RATE =000
RATE =001
RATE =010
RATE =011
RATE =100
RATE =101
RATE =110
32kHz
4.096
6.144
8.192
12.288
16.384
24.576
36.864
44.1kHz
5.6448
8.467
11.2896
16.9344
22.5792
33.8688
Unavailable
24.576
36.864
Unavailable
48kHz
6.144
9.216
12.288
18.432
88.2kHz
11.2896
16.9344
22.5792
33.8688
Unavailable Unavailable Unavailable
36.864
Unavailable Unavailable Unavailable
96kHz
12.288
18.432
24.576
176.4kHz
22.5792
33.8688
Unavailable
Unavailable Unavailable Unavailable Unavailable
192kHz
24.576
36.864
Unavailable
Unavailable Unavailable Unavailable Unavailable
Table 13 Master Mode MCLK / LRCLK Frequency Selection
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
R9
PAIF 1
09h
2:0
PAIFRX_RATE
[2:0]
010
R10
PAIF 2
0Ah
2:0
PAIFTX_RATE
[2:0]
010
R11
SAIF 1
0Bh
2:0
SAIF_RATE
[2:0]
010
DESCRIPTION
Master Mode MCLK/LRCLK
Ratio:
000 = 128fs
001 = 192fs
010 = 256fs
011 = 384fs
100 = 512fs
101 = 768fs
110 = 1152fs
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
R10
PAIF 2
0Ah
4:3
PAIFTX_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.
R11
SAIF 1
0Bh
4:3
SAIF_BCLKSEL
[1:0]
00
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
2
I S 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
R12
PAIF 3
0Ch
1:0
PAIFRXFMT
[1:0]
10
PAIF Receiver Audio Data Format
Select
11: DSP Format
2
10: I S 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
1:0
PAIFTXFMT
[1:0]
10
PAIF Transmitter Audio Data Format
Select
11: DSP Format
2
10: I S 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
R13
PAIF 4
0Dh
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REGISTER
ADDRESS
R14
SAIF 2
0Eh
BIT
LABEL
DEFAULT
DESCRIPTION
5
PAIFTXBCP
0
PAIF Receiver BCLK polarity
0 = BCLK not inverted
1 = BCLK inverted
1:0
SAIFFMT
[1:0]
10
SAIF Audio Data Format Select
11: DSP Format
10: I2S Format
01: Left justified
00: Right justified
3:2
SAIFWL
[1:0]
10
SAIF Audio Data Word Length
11: 32 bits (see Note 1,2)
10: 24 bits
01: 20 bits
00: 16 bits
4
SAIFLRP
0
In LJ/RJ/I S modes
0 = LRCLK not inverted
1 = LRCLK inverted
In DSP Format:
0 = DSP Mode A
1 = DSP Mode B
5
SAIFBCP
0
SAIF BCLK polarity
0 = BCLK not inverted
1 = BCLK inverted
6
SAIF_EN
0
SAIF Enable
0 = SAIF disabled
1 = SAIF enabled
2
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.
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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
DEFAULT
R15
DAC CONTROL 1
0Fh
1:0
DAC1SEL
[1:0]
00
3:2
DAC2SEL
[1:0]
01
5:4
DAC3SEL
[1:0]
10
7:6
DAC4SEL
[1:0]
11
DESCRIPTION
DAC digital input select
00 = DAC takes data from
01 = DAC takes data from
10 = DAC takes data from
11 = DAC takes data from
DIN1
DIN2
DIN3
DIN4
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
R12
PAIF 3
0Ch
6
DACOSR
0
DESCRIPTION
DAC Oversampling Rate Control
0= 128x oversampling
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
R16
DAC CONTROL 2
10h
3:0
PL[3:0]
1001
DESCRIPTION
PL[3:0]
Left O/P
Right O/P
0000
Mute
Mute
0001
Left
Mute
0010
Right
Mute
0011
(L+R)/2
Mute
0100
Mute
Left
0101
Left
Left
0110
Right
Left
0111
(L+R)/2
Left
1000
Mute
Right
1001
Left
Right
1010
Right
Right
1011
(L+R)/2
Right
1100
Mute
(L+R)/2
1101
Left
(L+R)/2
1110
Right
(L+R)/2
1111
(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
R16
DAC CONTROL 2
10h
6:4
DZFM[2:0]
000
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
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
R20
DIGITAL
ATTENUATION
DACL 1
14h
7:0
LDA1[7:0]
11111111
(0dB)
8
UPDATE
Not latched
R21
DIGITAL
ATTENUATION
DACR 1
15h
7:0
RDA1[6:0]
11111111
(0dB)
8
UPDATE
Not latched
R22
DIGITAL
ATTENUATION
DACL 2
16h
7:0
LDA2[7:0]
11111111
(0dB)
8
UPDATE
Not latched
R23
DIGITAL
ATTENUATION
DACR 2
17h
7:0
RDA2[7:0]
11111111
(0dB)
8
UPDATE
Not latched
R24
DIGITAL
ATTENUATION
DACL3
18h
7:0
LDA3[7:0]
11111111
(0dB)
8
UPDATE
Not latched
R25
DIGITAL
ATTENUATION
DACR3
19h
7:0
RDA3[7:0]
11111111
(0dB)
8
UPDATE
Not latched
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DESCRIPTION
Digital Attenuation control for DAC1 Left Channel (DACL1) in 0.5dB
steps. See Table 23
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
Digital Attenuation control for DAC1 Right Channel (DACR1) in
0.5dB steps. See Table 23
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.
Digital Attenuation control for DAC2 Left Channel (DACL2) in 0.5dB
steps. See Table 23
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.
Digital Attenuation control for DAC2 Right Channel (DACR2) in
0.5dB steps. See Table 23
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.
Digital Attenuation control for DAC3 Left Channel (DACL3) in 0.5dB
steps. See Table 23
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.
Digital Attenuation control for DAC3 Right Channel (DACR3) in
0.5dB steps. See Table 23
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.
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REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
R26
DIGITAL
ATTENUATION
DACL4
1Ah
7:0
RDA4[7:0]
11111111
(0dB)
8
UPDATE
Not latched
R27
DIGITAL
ATTENUATION
DACR4
1Bh
7:0
MASTDA[7:0]
11111111
(0dB)
8
UPDATE
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.
R28
MASTER
DIGITAL
ATTENUATION
1Ch
7:0
MASTDA[7:0]
11111111
(0dB)
Digital Attenuation control for all DAC channels in 0.5dB steps. See
Table 23
8
UPDATE
Not latched
Digital Attenuation control for DAC4 Left Channel (DACL4) in 0.5dB
steps. See Table 23.
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.
Digital Attenuation control for DAC4 Right Channel (DACR4) in
0.5dB steps. See Table 23
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.
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)
-0.5dB
FF(hex)
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
R19
DAC CONTROL 5
13h
BIT
6
LABEL
DACATC
DEFAULT
0
DESCRIPTION
Attenuator Control
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
R19
DAC CONTROL 5
13h
5
DZCEN
0
DESCRIPTION
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. A soft-mute allows the user to control the analog output of the DAC such that the output
waveform is looks like that shown in Figure 24.
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)
PL(3:0)
DACPD(3:0)
MUTEALL
DZFM (2:0)
MUTE
(register)
Decode
DAC_SRC[1:0] = 00
PCM_N or
AUDIO_N = 1
MPDENB
MUTE
(pin)
DZFM
Selector
Channel 1
Softmute
Channel 2
Softmute
Channel 3
Softmute
zflag1
DAC1 i/p
DAC2 i/p
DAC3 i/p
1024
Zeros
Detect
zflag2
zflag3
Channel 4
Softmute
zflag4
DAC4 i/p
DAC_SRC[1:0] = 00
UNLOCK = 1
Channel 1
Analogue
Mute
Channel 2
Analogue
Mute
Channel 3
Analogue
Mute
Channel 4
Analogue
Mute
IZD
Decode
(register)
Volume
LDAx/RDAx
(Digital volume)
Figure 23 Mute Circuit Diagram
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REGISTER ADDRESS
BIT
LABEL
DEFAULT
R19
DAC CONTROL 5
13h
3:0
DMUTE[3:0]
0000
DESCRIPTION
4
MUTEALL
0
DAC channel master soft mute.
Mutes all DAC channels:
0 = disable soft-mute on all
DACs.
1 = enable soft-mute on all
DACs.
7
MPDENB
0
MUTE pin decode enable:
0 = MUTE activates soft-mute
on DAC selected by DZFM
1 = MUTE activates softmute
on all DACs
DAC channel soft mute
enables:
DMUTE[0] = 1, enable softmute on DAC1.
DMUTE[1] = 1, enable softmute on DAC2.
DMUTE[2] = 1, enable softmute on DAC3.
DMUTE[3] = 1, enable softmute on DAC4.
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
0.004
0.005
0.006
Time(s)
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.
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All other means of muting the DAC channels will cause a much more abrupt muting of the output.
This abrupt muting is referred to as an analog mute and it will switch the analog outputs immediately
to VMID.
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 deemphasis filter for DAC 3 and DEEMP[3] enables the de-emphasis filter for DAC 4.
REGISTER ADDRESS
BIT
LABEL
DEFAULT
R17
DAC CONTROL 3
11h
3:0
DEEMP[3:0]
0000
4
DEEMPALL
0
DESCRIPTION
De-emphasis mode select:
DEEMP[0] = 1, enable Deemphasis on DAC1.
DEEMP[1] = 1, enable Deemphasis on DAC2.
DEEMP[2] = 1, enable Deemphasis on DAC3.
DEEMP[3] = 1, enable Deemphasis on DAC4.
0 = De-emphasis controlled by
DEEMP[3:0]
1 = De-emphasis enabled on all
DACs
Table 27 De-emphasis Register
Refer to, Figure 47, Figure 48, Figure 49 and Figure 50 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
R18
DAC CONTROL 4
12h
7:0
PHASE
[7:0]
11111111
DESCRIPTION
Controls phase of DAC outputs
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
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
R29
ADC CONTROL 1
1Dh
BIT
4
LABEL
ADCHPD
DEFAULT
0
DESCRIPTION
ADC high-pass filter disable
0 = high-pass filter enabled
1 = high-pass filter disabled
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
R29
ADC CONTROL 1
1Dh
3
ADCOSR
0
DESCRIPTION
ADC oversample rate select
0 = 128/64x oversampling
1 = 64/32x oversampling
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
AMUTER
0
ADC Mute select
0 : Normal Operation
1: mute ADC right
2
AMUTEALL
0
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
8:7
PAIFTX_SRC
[1:0]
01
Primary Audio Interface Tx Source:
00 = S/PDIF received data.
01 = ADC digital output data.
10 = SAIF Rx data
R14
8:7
SAIFTX_SRC
[1:0]
00
Secondary Audio Interface Tx Source:
00 = S/PDIF received data.
01 = ADC digital output data.
11 = PAIF Rx data
R30
1:0
TXSRC
[1:0]
00
S/PDIF Transmitter Data Source.
00 = S/PDIF received data(‘thrupath’)
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 similar flexible clock
configuration capability. The user can chose which clock drives each of the main functional blocks. In
general the choice of clock is between MCLK, ADCMCLK, PLLACLK and PLLBCLK, with some
restrictions dependant upon the digital routing configuration. An example of the restrictions is if the
S/PDIF receiver is routed to DAC1, then the appropriate clock for DAC1 is autoconfigured. Not all 4
clocks are available to all main function blocks. For the purposes of description, Table 33 defines the
signal names and descriptions used in the following sections.
SIGNAL NAME
DESCRIPTION
MCLK
System Master Clock pin
ADCMCLK
ADC Masetr clock input pin (MFP2)
PLLACLK
Output of PLLA (following any programmed division)
PLLBCLK
Output of PLLB (following any programmed division)
DAC_CLK
The internal clock driving all DAC functional blocks
DAC_CLK_SEL
User programmed register select bits to select DAC_CLK (Reg8, bits 1:0)
DAC_CLK_SEL_I
Internally generated multiplexer select bits to select DAC_CLK – generated based on
DAC_CLK_SEL register bits and digital routing configuration.
The internal clock driving the ADC functional block
ADC_CLK
ADC_CLK_SEL
Internally generated multiplexer select bits to select ADC_CLK – generated based on
ADC_CLK_SEL register bits and digital routing configuration.
User programmed register select bits to select ADC_CLK (Reg8, bits 3:2)
TX_CLK
The internal clock driving the S/PDIF Tx functional block
TX_CLKSEL_I
Internally generated multiplexer select bits to select TX_CLK – generated based on
TX_CLKSEL register bits and digital routing configuration.
User programmed register select bits (Reg8, bits 5:4) to select TX_CLK
ADC_CLK_SEL_I
TX_CLKSEL
PAIFRXMS_CLKSEL
PAIFRXMS_CLKSEL_I
PAIFTXMS_CLKSEL
PAIFTXMS_CLKSEL_I
SAIF_CLKSEL
SAIF_CLKSEL_I
User programmed register select bits (Reg9, bits 7:6) to select PAIF Rx interface input
clock when the PAIF Rx is configured in master mode. In master mode, the PAIF Rx
generates a BCLK and an LRCLK from the selected clock source. When in Slave
mode the PAIF Rx uses the input pins PAIFRX_BCLK and PAIFRX_LRCLK
Internally generated multiplexer select bits to select PAIF Rx clock source – generated
based on PAIFRXMS_CLKSEL register bits and digital routing configuration.
User programmed register select bits (Reg??, bits ??) to select PAIF Tx interface input
clock when the PAIF Tx is configured in master mode. In master mode, the PAIF Tx
generates a BCLK and an LRCLK from the selected clock source. When in Slave
mode the PAIF Tx uses the input pins PAIFTX_BCLK (MFP1) and PAIFTX_LRCLK
Internally generated multiplexer select bits to select PAIF Rx clock source – generated
based on PAIFRXMS_CLKSEL register bits and digital routing configuration.
User programmed register select bits (Reg11, bits 7:6) to select SAIF (Tx and Rx)
interface input clock when the SAIF is configured in master mode. In master mode,
the SAIF generates a BCLK and an LRCLK from the selected clock source. When in
Slave mode the SAIF uses the input pins SAIF_BCLK (MFP6) and SAIF_LRCLK
(MFP7).
Internally generated multiplexer select bits to select SAIF clock source – generated
based on SAIF_CLKSEL register bits and digital routing configuration.
Table 33 Definition of Signal Names for Purpose of Description
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It is possible to override any autoconfiguration of clocks, allowing the user to manually select an
available clock for a particular interface using the appropriate CLKSEL register bits. The
autoconfiguration can be overridden using the CLKSEL_MAN bit (Reg6, bit 6). Great care must to
used when overriding autoconfigured clocking.This is described in Manual Clock Selection section.
The sample rate at which the DAC, ADC and S/PDIF interfaces operate is configurable. The rate of
operation is determined by the available LRCLK at the interface and how the interface is configured –
master or slave mode. The available options are described in the sections which follow.
The PAIF and SAIF generate a BLCK and LRCLK if in master mode. In slave mode they use the
clocks from input pins.
DAC INTERFACE
The DACs are driven from an internal clock called the DAC_CLK. The DAC_CLKSEL bits (reg8, bits
1:0) select a clock to drive the DAC and the possible sources of DAC_CLK are MCLK, PLLACLK or
PLLBCLK. The digital routing can override the programmed DAC_CLKSEL register bits. For
example, if DAC1 is sourcing the S/PDIF Receiver, then PLLACLK is automatically selected as the
DAC_CLK. Figure 26 illustrates the DAC clock selection and the DAC Rate selection (see next
section).
Figure 26 DAC Clock and DAC Rate Selection
DAC RATE SELECTION
The sampling rate at which a DAC operates is determined by the DAC rate module, which is part of
the DAC. The DAC rate module divides down the DAC_CLK and calculates the rate at which the
DAC operates based on the DAC_CLK and the DAC_RATE_SEL (refer to Figure 26). The
DAC_RATE_SEL is generated based on the digital routing setup, and selects between
128/192/256/384/512/768/1152fs.Table 34 describes which clock is used to calculate the DAC rate.
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DAC Data Source
Clock used for DAC
rate Generator (fs)
Comments
DAC1 =PAIFRX
PAIFRX_LRCLK
DAC sample rate based on PAIF Rx
DAC1=SAIFRX
SAIFRX_LRCLK
DAC sample rate based on SAIF Rx
DAC1=S/PDIFRX
SFRM_CLK or
PAIFRX_LRCLK
RX2DAC_MODE bit selects between the
SFRM_CLK (default) and the
PAIFRX_LRCLK.
SFRM_CLK
Set RX2DAC_MODE=0
PAIFRX_LRCLK
Need to synchronise the DACs to use the a
common LRCLK.Set RX2DAC_MODE=1
and S/PDIF Rx sampling rate must be
synchronous to PAIF_LRCLK
(DAC2/3/4 also used)
DAC1=S/PDIFRX
(DAC2/3/4 NOT used)
DAC1=S/PDIFRX
DAC 2/3/4 = PAIFRX
Table 34 DAC Sample Rate Selection
If DACs 2,3 and 4 source the PAIFRX, while DAC 1 sources the S/PDIFRx then to synchronize all
DACs together, the DAC rate generator needs to use a common LRCLK. In this case, the
PAIFRX_LRCLK should be used. This is done by setting register bit RX2DAC_MODE=1, allowing the
PAIF_LRCLK to be used to generate the sampling rate. In this case, the S/PDIF sampling rate must
be synchronised with PAIF_LRCLK. In addition, when using the S/PDIF receiver, the PLLACLK and
PLLBCLK are not available to the DACs, and the DAC_CLK applied to the DACs must be at a
standard audio rate.
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
R8
CLKSEL
08h
1:0
DAC_CLKSEL
00
DAC clock source
00 = MCLK pin
01 = PLLACLK
10 = PLLBCLK
11 = MCLK pin
R15
DAC
Control 1
0Fh
8
RX2DAC_MODE
0
DAC oversampling rate and power down
control (only valid when DAC_SRC = 00,
DAC1 data sourced from S/PDIF receiver)
0 = SFRM_CLK determines
oversampling rate, DACs 2/3/4
powered down
1 = PAIFRX_LRCLK determines
oversampling rate, DACs 2/3/4 source
PAIF Receiver
Table 35 DAC Clock Control
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ADC INTERFACE
The ADC_CLKSEL register selects the ADC_CLK clock source from ADCMCLK, PLLACLK,
PLLBCLK, or MCLK.
If the S/PDIF receiver is enabled, PLLACLK and PLLBCLK are invalid for ADC operation, so the
choice is limited to ADCMCLK (default) or MCLK. Figure 27 illustrates this.
ADCMCLK (MFP2)
00
01
10
11
PLLACLK
PLLBCLK
MCLK
ADC_CLK
ADC_CLKSEL(R8[3:2])
If the S/PDIF Rx is disabled then
ADC_CLKSEL controls the
ADC_CLK clock selection
Tie
0
11
11
1
ADC
ADC_CLKSEL_I
Tie
00
00,01,11
SPDIFRX_EN
If the S/PDIF Rx is enabled, then ADC_CLK is
forced to ADCMCLK (when ADC_CLKSEL =
00,01 or 10) or ADC_CLK is forced to MCLK pin
(when ADC_CLKSEL=11)
PAIFTX_LRCLK
SAIF_LRCLK (MFP7)
ADC_RATE (R29[7:5])
ADC Rate
Select
ADC_RATE_SEL
Figure 27 ADC Clock and ADC Rate Selection
The sample rate at which the ADC operates is determined by the ADC Rate module. which is part of
the ADC. The ADC rate module divides down the ADC_CLK and calculates the rate at which the
ADC operates based on the ADC_CLK, the ADC_RATE and the digital routing setup. These 3 things
combine to generate the ADC_RATE_SEL. Table 36 summerises the sample rate selection based
on what sources the ADC output.
ADC Data Destination
Clock used for ADC
rate Generator (fs)
Comments
PAIFTX =ADC
PAIFTX_LRCLK
ADC sample rate based on PAIF Tx
SAIFTX =ADC
SAIF_LRCLK
Assumes that PAIF sources another
interface then ADC sample rate based on
SAIF Tx
S/PDIFTX =ADC
ADC_RATE
ADC sample rate determined by the
ADC_RATE register bits R29,bits 7:5
Table 36 ADC Rate Selection
The ADC_CLK clock source can be independent from the DACs and PLLs, however for optimum
performance t is recommended that clock sources on the WM8581 are synchronous. If this condition
is not met performance may be degraded.
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REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
R8
CLKSEL
08h
3:2
ADC_CLKSEL
00
ADC clock source
00 = ADCMCLK pin
01 = PLLACLK
10 = PLLBCLK
11 = MCLK pin
R29
ADC
Control 1
1Dh
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
Table 37 ADC Clock Control
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S/PDIF INTERFACES
The TX_CLKSEL register selects S/PDIF Transmitter clock, TX_CLK, from ADCMCLK, PLLACLK,
PLLBCLK, or MCLK. Figure 28 illustrates how the clock is selected.
The S/PDIF Receiver only uses PLLACLK, but both PLLACLK and PLLBCLK are unavailable in user
mode when the S/PDIF receiver is active. If the digital routing is configured such that the S/PDIF
Transmitter is sourcing the S/PDIF Receiver, then PLLACLK is automatically selected.
Figure 28 S/PDIF TX Clock and Rate Selection
The rate at which the S/PDIF Transmitter operates is determined by the S/PDIF transmitter rate
module which is part of the S/PDIF Tx interface. The transmitter rate module calculates the rate
based on the digital routing setup. Table 38 summerises the sample rate selection based on the
S/PDIFTx interface source data.
S/PDIF Tx Data Source
Clock used for S/PDIF
rate Generator (fs)
Comments
S/PDIF Tx = S/PDIF RX
SFRM_CLK
S/PDIF Tx sample rate based on S/PDIF Rx
S/PDIF Tx = PAIF RX
PAIFRX_LRCLK
S/PDIF Tx sample rate based on PAIF Rx
S/PDIF Tx = SAIF RX
SAIFRX_LRCLK
S/PDIF Tx sample rate based on SAIF Rx
S/PDIF Tx = ADC
PAIFTX_LRCLK or the
ADC_RATE
PAIFTX_LRCLK if PAIFTX also sources the
ADC. ADC_RATE register otherwise.
Table 38 S/PDIF Tx Rate Selection
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REGISTER
ADDRESS
BIT
LABEL
DEFAULT
R8
CLKSEL
08h
5:4
TX_CLKSEL
01
DESCRIPTION
S/PDIF Transmitter clock source
00 = ADCMCLK pin
01 = PLLACLK
10 = PLLBCLK
11 = MCLK pin
Table 39 S/PDIF Transmitter Clock Control
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). Register
R9, bit 5 selects master or slave mode.
In Slave mode, the BCLK and LRCLK driving the PAIF Rx interface are the PAIFRX_BCLK and the
PAIFRX_LRCLK pins.
In master mode the BCLK and LRCLK driving the PAIF Rx are generated by the Master Mode Clock
Gen module. The control of this module is described on page 22. The clock supplied to this module
is selected by the PAIFRXMS_CLKSEL register bits. These bits select either MCLK, PLLACLK, or
PLLBCLK unless the S/PDIF Rx interface is enabled in which case the PAIF Rx clock is forced to use
the MCLK pin since the PLLA and PLLB are not available in this mode.
Figure 29 PAIF Rx Interface Clock Configuration
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
R9
PAIF 1
09h
7:6
PAIFRXMS_
CLKSEL
00
DESCRIPTION
PAIF Receiver Master Mode clock
source
00 = MCLK pin
01 = PLLACLK
10 = PLLBCLK
11 = MCLK pin
Table 40 PAIF Rx Master Mode Clock Control
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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).
Register R10, bit 5 selects master or slave mode.
In Slave mode, the BCLK driving the PAIF Tx interface is either the PAIFTX_BCLK pin (default) or
the PAIFRX_BCLK pin (if ADC is using MCLK pin). The LRCLK driving the PAIF Tx interface is the
PAIFRX_LRCLK
In master mode the BCLK and LRCLK driving the PAIF Tx interface are generated by the Master
Mode Clock Gen module. The control of this module is described on page 22.
The clock supplied to the Master Mode Clock Gen module can be ADCMCLK, PLLACLK, PLLBCLK,
or MCLK. Selection is automatic and is based on the digital routing configuration. Figure 30 illustrates
the clock configuration and Table 41 gives some examples of clock routing based on digital routing
configuration.
Figure 30 PAIF Tx Interface Clock Configuration
Digital Routing
Comments
Configuration
Clock used by PAIF Tx
Master Mode Clock
Generator
PAIF Tx = S/PDIF RX
PLLACLK
Recommend to operate PAIF Tx in master
mode
PAIF Tx = SAIF RX
Same as ADC_CLK
PAIF Tx selects the same as ADC_CLK_I
Table 41 PAIF Tx Clock Configuration Examples
Secondary Audio Interfaces (SAIF Rx & SAIF TX)
The SAIF Transmit and Receive interfaces 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). Register R11, bit 5 selects master or slave mode.
In Slave mode, the BCLK driving the SAIF interface is the SAIF_BCLK pin and the LRCLK driving the
SAIF interface is the SAIF_LRCLK pin
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In master mode the BCLK and LRCLK driving the SAIF interface are generated by the Master Mode
Clock Gen module. The control of this module is described on page 22.
The clock supplied to the Master Mode Clock Gen module can be ADCMCLK, PLLACLK, PLLBCLK,
or MCLK. Selection is automatic and is based on the digital routing configuration. Figure 31 illustrates
the clock configuration and Table 42 SAIF Clock Configuration Examplesgives some examples of
clock routing based on digital routing configuration.
If the digital routing is 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, then the PLLACLK and PLLBCLK are invalid for SAIF operation, so
the choice forced to MCLK (default) or ADCMCLK.
Figure 31 SAIF Interface Clock Configuration
Digital Routing
Comments
Configuration
Clock used by SAIF
Master Mode Clock
Generator
SAIF Tx = S/PDIF RX
PLLACLK
Recommend to operate SAIF in master
mode
SAIF Tx = PAIF RX
MCLK
Set SAIFMS_CLKSEL = 11
Table 42 SAIF Clock Configuration Examples
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
R11
SAIF 1
0Bh
7:6
SAIFMS_
CLKSEL
11
DESCRIPTION
SAIF Master Mode clock source
00 = ADCMCLK pin
01 = PLLACLK
10 = PLLBCLK
11 = MCLK pin
Table 43 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. Figure 32 to Figure 37 illustrate this over-ride
capability.
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
R8
CLKSEL
08h
6
CLKSEL_MAN
0
DESCRIPTION
Clock selection auto-configuration
override
0 = auto-configuration enabled,
clock configuration follows
restrictions described in page 39
to page 50.
1 = auto-configuration disabled,
clock configuration follows
relevant CLKSEL bits in R8 to
R11.
Table 44 Manual Clock Selection
Figure 32 Manual Clock Over-ride of DAC Clock
Figure 33 Manual Clock Over-ride of ADC Clock
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Figure 34 Manual Clock Over-ride of S/PDIF Tx Clock
Figure 35 Manual Clock Over-ride of PAIF Tx
Figure 36 Manual Clock Over-ride of PAIF Rx
Figure 37 Manual Clock Over-ride of SAIF
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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 38.
Figure 38 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 55.
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 45.
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 45 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 46.
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
R51
PWRDN 2
33h
1
PLLAPD
1
2
PLLBPD
1
DESCRIPTION
PLL Power Down Control
0 = Power Up PLL
1 = Power Down PLL
Table 46 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 51) 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 47 and Table 49 for details of the registers available for configuration in this mode.
Refer to the S/PDIF Receive Mode Clocking section on page 58 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 postscale divider values and can hence fully control the generated clock frequencies.
Refer to Table 47 and Table 49 for details of the registers available for configuration in this mode.
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
R0
PLLA 1/
DEVID1
00h
8:0
PLLA_K[8:0]
100100001
R1
PLLA 2/
DEVID2
01h
8:0
PLLA_K[17:9]
101111110
R2
PLLA 3/
DEVREV
02h
3:0
PLLA_K[21:18]
1101
DESCRIPTION
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.
Reading from these registers will
return the device ID.
R0 returns 10000001 = 81h
R1 returns 10000101 = 85h
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.
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R4
PLLB 1
04h
8:0
PLLB_K[8:0]
100100001
R5
PLLB 2
05h
8:0
PLLB_K[17:9]
101111110
R6
PLLB 3
3:0
PLLB_K[21:18]
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.
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.
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REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
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 47 User Mode PLL_K and PLL_N Multiplier Control
Parameter
PRESCALE_A
PRESCALE_B
PLLA_N
PLLA_K
PLLB_N
PLLB_K
FREQMODE_A
FREQMODE_B
POSTSCALE_A
POSTSCALE_B
PLL User Mode
Manual
Manual
Manual
Manual
Manual
Manual
Manual
Manual
Manual
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
256fs/128fs PLLACLK Select
Not Used
Table 48 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
47). 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 49 for details.
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REGISTER
ADDRESS
BIT
LABEL
DEFAULT
R3
PLLA 4
03h
0
PRESCALE_A
0
R7
PLLB 4
07h
0
PRESCALE_B
0
R3
PLLA 4
03h
4:3
FREQMODE_A
[1:0]
10
R7
PLLB 4
07h
4:3
FREQMODE_B
[1:0]
10
R3
PLLA 4
03h
1
POSTSCALE_A
0
R7
PLLB 4
07h
1
POSTSCALE_B
0
DESCRIPTION
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.
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
50.
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 51.
PLL User Mode
Used in conjunction with the
FREQMODE_x bits. Refer to Table
50.
Table 49 Pre and Post PLL Clock Divider Control
FREQMODE_x[1:0]
f2 TO PLLxCLK DIVISION FACTOR
POSTSCALE_x
0
1
00
÷2
÷4
01
÷4
÷8
10
÷8
÷16
11
÷12
÷24
Table 50 PLL User Mode Clock Divider Configuration
POSTSCALE_A
PLLACLK FREQUENCY
0
256fs
1
128fs
Table 51 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.
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.
1.
•
POSTSCALE_B = 0
•
FREQMODE_B [1:0] = 10b
•
f2 = 98.304MHz
Calculate R Value
Using the relationship: R = (f2 ÷ f1), the value of R can be calculated.
2.
•
R = (f2 ÷ f1)
•
R = (98.304 ÷ 12)
•
R = 8.192
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.
3.
Calculate PLL_K Value
22
The PLLB_K value is simply the integer value of (2
22
(R-PLLB_N)).
•
PLLB_K = integer part of (2
•
PLLB_K = integer part of 805306.368
•
PLLB_K = 805306 (decimal) / C49BA (hex)
x (8.192 – 8))
A number of example configurations are shown in Table 52. Many other configurations are possible;
Table 52 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
CLK
(MHz)
PRESCALE
_x
F1
(MHz)
F2
(MHz)
R
PLLx_N
(Hex)
PLLx_K
(Hex)
FREQ
MODE_x
[1:0]
POSTSCALE_x
PLLxCLK
(MHz)
12
0
12
98.304
8.192
8
C49BA
00
1
24.576
12
0
12
98.304
8.192
8
C49BA
01
0
24.576
12
0
12
98.304
8.192
8
C49BA
01
1
12.288
12
0
12
98.304
8.192
8
C49BA
10
0
12.288
12
0
12
98.304
8.192
8
C49BA
10
1
6.144
12
0
12
98.304
8.192
8
C49BA
11
0
8.192
12
0
12
98.304
8.192
8
C49BA
11
1
4.096
24
1
12
90.3168
7.5264
7
21B089
00
1
22.5792
24
1
12
90.3168
7.5264
7
21B089
01
0
22.5792
24
1
12
90.3168
7.5264
7
21B089
01
1
11.2896
24
1
12
90.3168
7.5264
7
21B089
10
0
11.2896
24
1
12
90.3168
7.5264
7
21B089
10
1
5.6448
24
1
12
90.3168
7.5264
7
21B089
11
0
7.5264
24
1
12
90.3168
7.5264
7
21B089
11
1
3.7632
27
1
13.5
98.304
7.2818
7
1208A5
00
1
24.576
27
1
13.5
98.304
7.2818
7
1208A5
01
1
12.288
27
1
13.5
90.3168
6.6901
6
2C2B24
00
1
22.5792
27
1
13.5
90.3168
6.6901
6
2C2B24
01
1
11.2896
Table 52 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 53.
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
8:7
CLKOUTSRC
11
CLKOUT pin source
00 = No Output (tristate)
01 = Output – Source PLLACLK
10 = Output – Source PLLBCLK
11 = Output – Source OSCCLK
Table 53 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 54 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
PRESCALE_X
S/PDIF RECEIVER
SAMPLE RATE(S) (kHz)
F1
(MHz)
F2
(MHz)
R
PLLB_N
(Hex)
PLLB_K
(Hex)
COMMENT
(MHz)
11.2896
0
32 / 44.1 / 48 / 88.2 / 96
8
16A3B3
Set N, K
12
0
32 / 44.1 / 48 / 88.2 / 96
11.2896 94.3104 8.3537
12
94.3104 7.8592
7
36FD21
Default Setting
12.288
0
32 / 44.1 / 48 / 88.2 / 96
12.288
94.3104 7.675
7
2B3333
Set K
19.2
1
32 / 44.1 / 48 / 88.2 / 96
9.6
94.3104 9.824
9
346C6A
Set Prescales, N, K
24
1
32 / 44.1 / 48 / 88.2 / 96
12
94.3104 7.8592
7
36FD21
Set Prescales
27
1
32 / 44.1 / 48 / 88.2 / 96
13.5
94.3104 6.986
6
3F19E5
Set Prescales, N, K
Table 54 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:
w
1.
Disable the PLLA and PLLB by seting the PLLAPD and PLLBPD bits
2.
Write appropriate calculated values (relative to
PRESCALE_A, PRESCALE_B, PLLB_N and PLLB_K.
3.
Enable S/PDIF receiver by clearing the SPDIFRXPD and SPDIFPD bits.
4.
Enable PLLA and PLLB by clearing the PLLAPD and PLLBPD bits.
oscillator
frequency)
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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 internal MCLK is
maintained at 256fs relative to the S/PDIF received sample rate. In hardware mode, the internal
MCLK is not available at the MCLK pin (the pin defaults to an input)
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.
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 subframes. Each sub-frame is made up of:
•
Preamble – a synchronization pattern used to identify the start of a 192-frame block or subframe
•
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 192frame S/PDIF Block. For Consumer mode only the first 40-frames are used to make up the Channel
and User blocks. Figure 39 illustrates the S/PDIF format.
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Frame
1
Subframe 1
0
34
Sync
preamble
Frame
192
.........
Subframe 2
78
27 28
Aux
Audio Sample Word
V
31
U
C
P
32 bit
Word
Figure 39 S/PDIF Format
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
R30
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
2
OVWCHAN
0
Overwrite Channel Status
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.
3
REAL_
THROUGH
0
S/PDIF Through Mode Control
0 = SPDIFOP pin sources output of S/PDIF Transmitter
1 = SPDIFOP pins sources output of S/PDIF IN Mux
4
TXVAL_
OVWR
0
S/PDIF Transmitter Validity Overwrite Mode
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
TXVAL_SF0
0
Overwrite Mode S/PDIF Transmitter Validity SubFrame 0
0 = transmit validity = 0
1 = transmit validity = 1
6
TXVAL_SF1
0
Overwrite Mode S/PDIF Transmitter Validity SubFrame 1
0 = transmit validity = 0
1 = transmit validity = 1
SPDTXCHAN 0
1Eh
R51
PWRDN 2
33h
4
SPDIFTXD
1
DESCRIPTION
S/PDIF Transmitter powerdown
0 = S/PDIF Transmitter enabled
1 = S/PDIF Transmitter disabled
Table 55 S/PDIF Transmitter Control
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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
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 subframe 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 56 to Table
60). 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
R31
0
CON/PRO
0
0
0 = Consumer Mode
1 = Professional Mode (not supported by
WM8581)
1
AUDIO_N
1
0
0 = S/PDIF transmitted data is audio PCM.
1 = S/PDIF transmitted data is not audio
PCM.
2
CPY_N
2
0
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 preemphasis.
001 = Data from Audio interface has preemphasis.
010 = Reserved (Audio interface has preemphasis).
011 = Reserved (Audio interface has preemphasis).
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.
SPDTXCHAN 1
1Fh
DESCRIPTION
Table 56 S/PDIF Transmitter Channel Status Bit Control 1
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REGISTER
ADDRESS
BIT
LABEL
CHANNEL
STATUS
BIT
DEFAULT
R32
7:0
CATCODE
[7:0]
15:8
00000000
SPDTXCHAN 2
20h
DESCRIPTION
Category Code. Refer to S/PDIF
specification IEC60958-3 for details.
00h indicates “general” mode.
Table 57 S/PDIF Transmitter Channel Status Bit Control 2
REGISTER
ADDRESS
BIT
LABEL
CHANNEL
STATUS
BIT
DEFAULT
DESCRIPTION
R33
3:0
SRCNUM
[3:0]
19:16
0000
Source Number. No definitions are attached
to data.
5:4
CHNUM1[1:0]
21:20
00
SPDTXCHAN 3
21h
7:6
CHNUM2[1:0]
00
23:22
Channel Number for Subframe 1
CHNUM1
Function
00
Do not use channel number
01
Send to Left Channel
10
Send to Right Channel
11
Do not use channel number
Channel Number for Subframe 2
CHNUM2
Function
00
Do not use channel number
01
Send to Left Channel
10
Send to Right Channel
11
Do not use channel number
Table 58 S/PDIF Transmitter Channel Status Bit Control 3
REGISTER
ADDRESS
BIT
LABEL
CHANNEL
STATUS
BIT
DEFAULT
R34
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.
SPDTXCHAN 4
22h
DESCRIPTION
Table 59 S/PDIF Transmitter Channel Status Bit Control 4
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REGISTER
ADDRESS
BIT
LABEL
CHANNEL
STATUS
BIT
DEFAULT
R35
0
MAXWL
32
1
3:1
TXWL[2:0]
35:33
101
SPDTXCHAN 5
23h
DESCRIPTION
Maximum Audio sample word length
0 = 20 bits
1 = 24 bits
Audio Sample Word Length.
000 = Word Length Not Indicated
TXWL[2:0]
MAXWL==1
MAXWL==0
001
20 bits
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 60 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
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)
WL_MASK
0
S/PDIF Receiver Word Length Truncation Mask
0 = disabled, data word is truncated as described in
Table 66.
1 = enabled, data word is not truncated.
6
R39
GPO2
27h
3:0
GPO3OP[3:0]
0010
7:4
GPO4OP[3:0]
0011
R40
GPO3
28h
3:0
GPO5OP[3:0]
0100
R51
PWRDN 2
33h
5
SPDIFRXD
1
DESCRIPTION
GPO pin Configuration Select.
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).
For GPO defaults, see Table 71.
S/PDIF Receiver powerdown
0 = S/PDIF Receiver enabled
1 = S/PDIF Receiver disabled
Table 61 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 71 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 S/PDIFRx interface always receives 24 bits of data in bits 4 to 27 of the SPDIF payload. The
audio sample can be either 20 bits if AUX bits not used or up to 24bits if AUX bits used (refer to
Figure 39). So the audio sample can be 20,21,22,23 or 24 bit. The source (wherever the S/PDIF data
is coming from) of the S/PDIF data stream must set the MAXWL and RXWL within the status bits to
indicate the size of the audio sample. This is then recovered by the S/PDIF Rx interface. The S/PDIF
Rx interface ALWAYS receives 24 bits, but if the actual length of the audio data sample (indicated by
MAXWL and RXWL) is less than 24 bits, then the user has the option to truncate these 24 bits to the
actual size. These truncated bits are then sent to either the SPDIF Tx or the AIF. Truncation may
allow users to process data faster. If the user does not want this truncation to happen then they must
mask the truncation using the WL_MASK. In this case all 24 bits of data received are transferred.
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The audio data sample can be transferred to either the AIF or the SPDIF Tx.
When the audio data sample is transferred to the AIF, and if the AIF is operating in a mode which has
less data bits, then the WM8581 will reduce the audio data sample to the length of the AIF. For
example, if the AIF is operating in 16 bit mode, but the SPDIF Rx receives an audio data sample
length of 21 bits, then the WM8581 will reduce the 21 bits to 16 bits by removing the LSBs. This
cannot be masked. If the AIF is operating in 24 bit mode, then the full 21 bits are transferred on the
AIF, with the LSBs set to 000.
When the audio data sample is transferred to the SPDIF TX, then the full audio data sample (24 bits)
is written to the SPDIF Tx. Unless it has been truncated using the WL-MASK bits
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.
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
R44
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.
1
AUDIO_N
1
-
Linear PCM Identification
0 = Data word represents audio PCM
samples.
1 = Data word does not represent audio
PCM samples.
2
CPY_N
2
-
0 = Copyright is asserted for this data.
1 = Copyright is not asserted for this data.
3
DEEMPH
3
-
0 = Recovered S/PDIF data has no preemphasis.
1 = Recovered S/PDIF data has preemphasis.
5:4
Reserved
5:4
-
Reserved for additional de-emphasis modes.
7:6
CHSTMODE
[1:0]
7:6
-
00 = Only valid mode for consumer
applications.
SPDRXCHAN 1
2Ch
(read-only)
DESCRIPTION
Table 62 S/PDIF Receiver Channel Status Register 1
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REGISTER
ADDRESS
BIT
LABEL
CHANNEL
STATUS
BIT
DEFAULT
DESCRIPTION
R45
7:0
CATCODE
[7:0]
15:8
-
Category Code.
Refer to S/PDIF specification IEC60958-3 for
details.
00h indicates “general” mode.
SPDRXCHAN 2
2Dh
(read-only)
Table 63 S/PDIF Receiver Channel Status Register 2
REGISTER
ADDRESS
BIT
LABEL
CHANNEL
STATUS
BIT
DEFAULT
DESCRIPTION
R46
3:0
SRCNUM
[3:0]
19:16
-
S/PDIF source number.
Refer to S/PDIF specification IEC60958-3 for
details.
5:4
CHNUM1[1:0]
21:20
-
Channel number for sub-frame 1.
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
7:6
CHNUM2[1:0]
23:22
SPDRXCHAN 3
2Eh
(read-only)
Channel number for sub-frame 2.
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 64 S/PDIF Receiver Channel Status Register 3
REGISTER
ADDRESS
BIT
LABEL
CHANNEL
STATUS
BIT
DEFAULT
DESCRIPTION
R47
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
01 = Level I
10 = Level III
11 = Interface frame rate not matched to
sampling frequency.
SPDRXCHAN 4
2Fh
(read-only)
Table 65 S/PDIF Receiver Channel Status Register 4
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REGISTER
ADDRESS
BIT
LABEL
CHANNEL
STATUS
BIT
DEFAULT
R48
0
MAXWL
32
-
Maximum Audio sample word length
0 = 20 bits
1 = 24 bits
3:1
RXWL[2:0]
35:33
-
Audio Sample Word Length.
000: Word Length Not Indicated
SPDRXCHAN 5
30h
(read-only)
DESCRIPTION
RXWL[2:0]
MAXWL==1
MAXWL==0
001
20 bits
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 66 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
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.
S/PDIF Status
Register, GPO
pins, SWMODE pin
(when in hardware
mode)
INVALID
Indicates that recovered S/PDIF data is marked as invalid.
0 = Data marked as valid
1 = Data marked as invalid
Interrupt Status
Register
Indicates that recovered S/PDIF frame has parity errors or bi-phase
encoding errors, or that sub-frames were recovered out of
sequence
0 = No data errors or bi-phase encoding errors detected and subframe sequence correct
1 = Data errors or bi-phase encoding errors detected or subframe
sequence incorrect (missing preamble)
Interrupt Status
Register
TRANS_ERR
AUDIO_N
Recovered Channel Status bit-1.
0 = Data word represents audio PCM samples.
1 = Data word does not represent audio PCM samples.
Channel Status
Register, S/PDIF
Status Register
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.
CPY_N
Recovered Channel Status bit-2 (active low)
0 = Copyright is asserted for this data.
1 = Copyright is not asserted for this data.
Channel Status
Register, S/PDIF
Status Register,
GPO pins
Recovered Channel Status bit-3
0 = Recovered S/PDIF data has no pre-emphasis.
1 = Recovered S/PDIF data has pre-emphasis
Channel Status
Register, S/PDIF
Status Register,
GPO pins
DEEMPH
REC_FREQ[1:0]
INT_N
Indicates recovered S/PDIF sample rate.
00 = Invalid
01 = 96kHz / 88.2kHz
10 = 48kHz / 44.1kHz
11 = 32kHz
Interrupt signal (see section Interrupt Generation)
S/PDIF Status
Register
S/PDIF Status
Register
GPO pins
V
Recovered validity-bit for current sub-frame
GPO pins
U
Recovered user-bit for current sub-frame
GPO pins
C
Recovered channel-bit for current sub-frame
GPO pins
P
Recovered parity-bit for current sub-frame
GPO pins
Indicates current sub-frame:
1 = Sub-frame A
0 = Sub-frame B
GPO pins
SFRM_CLK
192BLK
Indicates start of 192 frame-block. High for duration of frame-0.
GPO pins
CSUD
Indicates that the 192 frame-block of channel status data has
updated.
GPO pins
ZFLAG
Indicates ‘zero-detection’ in DACs. See page 45 for more details
NON_AUDIO
Logical OR of PCM_N and AUDIO_N
MUTE pin, GPO
pins
GPO pins, SDO pin
(when in hardware
mode)
Table 67 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
R43
INTSTAT
2Bh
(read-only)
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
1
INT_INVALID
-
INVALID flag interrupt signal
0 = INT_N not caused by INVALID flag
1 = INT_N caused by INVALID flag
2
INT_CSUD
-
CSUD flag interrupt signal
0 = INT_N not caused by CSUD flag
1 = INT_N caused by CSUD flag
3
INT_TRANS
-
TRANS_ERR flag interrupt signal
0 = INT_N not caused by TRANS_ERR flag
1 = INT_N caused by TRANS_ERR flag
_ERR
DESCRIPTION
4
UPD_NON_AUDIO
-
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
5
UPD_CPY_N
-
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
6
UPD_DEEMPH
-
DEEMPH update signal
0 = INT_N not caused by update to DEEMPH flag
1 = INT_N caused by update to DEEMPH flag
7
UPD_REC_FREQ
-
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 68 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 69 The SPDSTAT
register will update if the received Rx S/PDIF data stream changes their values.
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REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
R49
SPDSTAT
31h
(read-only)
0
AUDIO_N
-
Recovered Channel Status bit-1.
0 = Data word represents audio PCM samples.
1 = Data word does not represent audio PCM samples.
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
CPY_N
-
Recovered Channel Status bit-2 (active low).
0 = Copyright is asserted for this data.
1 = Copyright is not asserted for this data.
3
DEEMPH
-
Recovered Channel Status bit-3
0 = Recovered S/PDIF data has no pre-emphasis.
1 = Recovered S/PDIF data has pre-emphasis
5:4
REC_FREQ
[1:0]
--
Indicates recovered S/PDIF clock frequency:
00 = Invalid
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 69 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 70 Interrupt Mask Control Register
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ERROR HANDLING IN SOFTWARE MODE
When the TRANS_ERR flag is asserted, it indicates that the recovered Rx S/PDIF sub-frame is
corrupted. This corruption can due to a BI-Phase error, a parity error or a pre-amble error.When the
INVALID flag is asserted, it indicates that the recovered Rx S/PDIF sub-frame has been marked as
being invalid by the source of the S/PDIF data. Both TRANS_ERR and INVALID indicate an error.
The S/PDIF receiver has two modes of handling for these errors, manual and automatic. The
mechanism for each flag is similar. The mechanisms are described below.
MANUAL ERROR HANDLING
This manual handling of errored Rx S/PDIF data can be used when an application processor is being
interrupted via the INT_N signal. Appropriate action should be taken by the application processor to
handle the error condition
If the TRANS_ERR and INVALID error flags are not masked using the MASK register, the recovered
S/PDIF Rx data is passed to the digital audio interface and DAC1 or to the S/PDIF transmitter
irrespective of the state of the flag and the data content of the recovered stream.(Also refer to note 1
below). In this case, the application processor will be interrupted via the INT_N signal.
AUTOMATIC ERROR HANDLING
This automatic handling of errored Rx S/PDIF data can be used when an application processor is not
being interrupted via the INT_N signal leaving the WM8581 to handle the error condition.
If the TRANS_ERR and INVALID error flags are masked using the MASK register, the WM8581
output data from the S/PDIF Rx interface depends on the setting of FILLMODE. If FILLMODE=1, then
the incoming data (which is errored) is overwritten with 0’s. If FILLMODE=0, then the last valid data
sample is repeatedly output.
For the INVALID flag, the automatic error handling can be disabled if ALWAYSVALID =1. If
ALWAYSVALID is set, then the recovered Rx S/PDIF data, which is marked as invalid, will be
allowed to pass to the digital audio interface or to the S/PDIF transmitter. The data will not be
modified in any way.
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
0 = INVALID flag automatic error handling enabled.
1 = INVALID flag automatic error handling disabled.
R39
GP02
27h
Table 65 S/PDIF Receiver Automatic Error Handling Configuration Registers
NON-AUDIO DETECTION
The SPDIF payload can contain PCM data for audio or non-audio applications. In the case where the
payload contains the 96 bit synchronization code defined in IEC61937 then this indicates that the
payload contains data which is not suitable for direct playback through an audio CODEC. This 96 bit
code is defined as 4*16bits of ‘0’+Pa (16bits)+Pb (16bits)..
If the SPDIFRx interface decodes this sync code then it sets the PCM_N bit.
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When the PCM_N =1, then it indicates non-audio data. When the PCM_N =0, then it indicates that
the SPDIF payload does not contain the synch code..
Another status bit, AUDIO_N status is recovered from the Channel Status block.It is bit 1 of the
channel status. When AUDIO_N =0, then it indicates that the SPDIF payload contains audio PCM
encoded data. This is also referred to as linear PCM data.When the AUDIO_N= 1, then it indicates
that the SPDIF payload does not contain audio PCM data.
NON_AUDIO data is indicated by a logical OR of the AUDIO_N and PCM_N flags.
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 soft mute 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.
S/PDIF INPUT/ GPO PIN CONFIGURATION
The WM8581 has seven pins which can be configured as GPOs using the registers shown in Table
71. 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 61.
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
R38
GPO1
26h
3:0
7:4
GPO1OP[3:0]
0000
GPO2OP[3:0]
0001
3:0
GPO3OP[3:0]
0010
7:4
GPO4OP[3:0]
0011
R40
GPO3
28h
3:0
GPO5OP[3:0]
0100
7:4
GPO6OP[3:0]
0101
R41
GPO4
29h
3:0
GPO7OP[3:0]
0110
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 (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
R39
GPO2
27h
Table 71 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.
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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.
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
4:2
DACPD[2:0]
111
DAC powerdowns
0 = DAC enabled
1 = DAC disabled
DACPD[0] = DAC1
DACPD[1] = DAC2
DACPD[2] = DAC3
6
ALLDACPD
1
Overrides DACPD[3:0]
0 = DACs under control of
DACPD[3:0]
1= All DACs are disabled.
0
OSCPD
0
OSC output powerdown
0 = OSC output enabled
1 = OSC output disabled
A CMOS input can be applied to
the OSC input when powered
down.
1
PLLAPD
1
0 = PLLA enabled
1 = PLLA disabled
2
PLLBPD
1
0 = PLLB enabled
1 = PLLB disabled
3
SPDIFPD
1
S/PDIF Clock Recovery
PowerDown
0 = S/PDIF enabled
1 = S/PDIF disabled
4
SPDIFTXD
1
S/PDIF Transmitter powerdown
0 = S/PDIF Transmitter enabled
1 = S/PDIF Transmitter disabled
5
SPDIFRXD
1
S/PDIF Receiver powerdown
0 = S/PDIF Receiver enabled
1 = S/PDIF Receiver disabled
R51
PWRDN 2
33h
Table 72 Powerdown Registers
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INTERNAL POWER ON RESET CIRCUIT
Figure 40 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 40 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 41 Typical Power up Sequence where DVDD is Powered before AVDD
Figure 42 Typical Power up Sequence where AVDD is Powered before DVDD
SYMBOL
MIN
TYP
MAX
UNIT
Vpora
0.5
0.7
1.0
V
Vporr
0.5
0.7
1.1
V
Vpora_off
1.0
1.4
2.0
V
Vpord_off
0.6
0.8
1.0
V
Table 73 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 41 and Figure 42 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 41 shows DVDD powering up before AVDD. Figure 42 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
R29
ADC CONTROL 1
1Dh
8
VMIDSEL
1
DESCRIPTION
VMID Impedance Selection
0 = High impedance, power
saving
1 = Low impedance, fast poweron
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
0
SWMODE
1
0
Software Control Hardware Control
2-wire control
1
3-wire control
Table 74 Hardware/Software Mode Setup
DIGITAL ROUTING CONTROL
See page 22 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 75 and Table 76.
PIN
0
1
DR1
DAC_SRC=S/PDIF receiver
DAC_SRC=PAIF receiver
DR2
PAIFTX_SRC=S/PDIF
receiver
PAIFTX_SRC=ADC output
Table 75 DR1 / DR2 Operation
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DR4
DR3
S/PDIF TRANSMITTER
DATA SOURCE
0
0
S/PDIF received data
0
1
ADC digital output data
1
0
Not available.
1
1
PAIF receiver data
Table 76 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.
PIN
FLAG
DESCRIPTION
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 77 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 78 below shows the options available.
CSB
SCLK
FORMAT & WORD LENGTH
0
0
24-bit right justified
0
1
20-bit right justified
1
0
24-bit left justified
1
1
24-bit I2S
Table 78 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 34 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
Floating
Normal Operation
Mute DAC channels
MUTE is an output to indicate when Zero Detection occurs on all DACs
(ZFLAG).
H = detected, L = not detected.
Table 79 MUTE Pin Control Options
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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 section Master and Slave Modes for more information on master mode operation.
SDIN
AUDIO INTERFACE (TX)
0
Slave
1
Master
Table 80 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
Powerup
1
Powerdown
Table 81 Hardware Mode Powerdown Control
HARDWARE CONTROL CLOCK ROUTING
In hardware mode the user has no access to the internal clock routing . In this mode the automatic
clock routing provides maximum functionality. In harware mode the OSCCLK must be 12MHz. no
other OSCCLK frequencies are supported.
MASTER MODE
If the S/PDIF Rx interface is enabled, then an internal MCLK is generated at 256fs. This internal
clock will act as a source clock for ADC, DACs and PAIF. The PAIF will output the PAIFTX_BCLK
and the PAIF_LRCLK. The MCLK is not available as an output (MCLK pin defaults to an input). The
SAIF is not available in hardware mode.
If the S/PDIF is disabled and the ADC is used as the source for the DACs or PAIF, then an MCLK
clock must be provided via the ADCMCLK input pin.
If the PAIF sources the ADC and the DACs source the S/PDIF, then the PAIF will operate from an
MCLK generated from the ADCMCLK input clock and the DACs will operate from an internal MCLK
(256fs) generated from S/PDIF interface.
SLAVE MODE
If the S/PDIF Rx interface is enabled, then an internal MCLK is generated at 256fs. This internal
clock will act as a source clock for ADC, DACs and PAIF. The user is required to supply input clocks
to the PAIFTX_BCLK and the PAIF_LRCLK.
If the PAIF or DACs source the S/PDIF Rx interface then the PAIFTX_BCLK and the PAIF_LRCLK
input clocks must be synchronous to clock driving the S/PDIF interface. If these clocks cannot be
guaranteed synchronous then this mode of operation is not recommended.
If the PAIF sources the ADC data, then the user must supply input clocks to ADCCLK,
PAIFTX_BCLK and the PAIF_LRCLK pins.
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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’. Not all registers can be read. Only the
device ID (registers R0, R1 and R2) and the status registers can be read. These status registers are labelled as “read only”
REGISTER
NAME
ADDRESS
B8
B7
B6
B5
B4
B3
R0
PLLA 1/DEVID1
00
PLLA_K[8:0]
R1
PLLA 2/DEVID2
01
PLLA_K[17:9]
R2
PLLA 3/DEVREV
02
0
R3
PLLA 4
03
0
R4
PLLB 1
04
PLLB_K[8:0]
R5
PLLB 2
05
PLLB_K[17:9]
R6
PLLB 3
06
R7
PLLB 4
07
R8
CLKSEL
08
0
0
0
0
FREQMODE_B[1:0]
09
0
PAIF 2
0A
0
R11
SAIF 1
0B
0
R12
PAIF 3
0C
DAC_SRC[1:0]
R13
PAIF 4
0D
PAIFTX_SRC[1:0]
R14
SAIF 2
0E
SAIFTX_SRC[1:0]
R15
DAC CONTROL 1
0F
RX2DAC_MODE
R16
DAC CONTROL 2
10
0
IZD
R17
DAC CONTROL 3
11
0
0
0
0
DEEMPALL
R18
DAC CONTROL 4
12
0
R19
DAC CONTROL 5
13
0
MPDENB
DACATC
DZCEN
MUTEALL
14
UPDATE
LDA1[7:0]
15
UPDATE
RDA1[7:0]
16
UPDATE
LDA2[7:0]
17
UPDATE
RDA2[7:0]
18
UPDATE
LDA3[7:0]
19
UPDATE
RDA3[7:0]
1A
UPDATE
LDA4[7:0]
1B
UPDATE
RDA4[7:0]
1C
UPDATE
MASTDA[7:0]
1D
VMIDSEL
R20
1
001111101
POSTSCALE_B PRESCALE_B
ADC_CLKSEL[1:0]
PAIF 1
DIGITAL ATTENUTATION
POSTSCALE_A PRESCALE_A
000010100
101111110
R9
DAC_CLKSEL[1:0]
110010100
000010000
PAIFRXMS
PAIFRX_BCLKSEL[1:0]
PAIFRX_RATE[2:0]
000000010
PAIFTXMS
PAIFTX_BCLKSEL[1:0]
PAIFTX_RATE[2:0]
000000010
SAIFMS
SAIF_BCLKSEL[1:0]
SAIF_RATE[2:0]
PAIFRXMS_CLKSEL[1:0]
0
001111101
PLLB_K[21:18]
R10
0
1
100100001
TX_CLKSEL[1:0]
_MAN
DEFAULT
101111110
FREQMODE_A[1:0]
MCLKOUTSRC[1:0]
CLKSEL
B0
PLLA_K[21:18]
PLLB_N[3:0]
CLKOUTSRC[1:0]
B1
100100001
PLLA_N[3:0]
0
0
B2
SAIFMS_CLKSEL[1:0]
011000010
PAIFRXBCP
PAIFRXLRP
PAIFRXWL[1:0]
PAIFRXFMT[1:0]
0
PAIFTXBCP
PAIFTXLRP
PAIFTXWL[1:0]
PAIFTXFMT[1:0]
010001010
SAIF_EN
SAIFBCP
SAIFLRP
SAIFWL[1:0]
SAIFFMT[1:0]
000001010
DAC1SEL[1:0]
011100100
DACOSR
DAC4SEL[1:0]
DAC3SEL[1:0]
DAC2SEL[1:0]
DZFM[2:0]
110001010
PL[3:0]
000001001
DEEMP[3:0]
000000000
PHASE[7:0]
011111111
DMUTE[3:0]
000000000
011111111
DACL 1
R21
DIGITAL ATTENUTATION
011111111
DACR 1
R22
DIGITAL ATTENUTATION
011111111
DACL 2
R23
DIGITAL ATTENUTATION
011111111
DACR 2
R24
DIGITAL ATTENUTATION
011111111
DACL 3
R25
DIGITAL ATTENUTATION
011111111
DACR 3
R26
DIGITAL ATTENUTATION
011111111
DACR 4
R27
DIGITAL ATTENUTATION
011111111
DACR 4
R28
MASTER DIGITAL
011111111
ATTENUTATION
R29
R30
R31
R32
R33
R34
ADC CONTROL 1
SPDTXCHAN 0
SPDTXCHAN 1
SPDTXCHAN 2
SPDTXCHAN 3
SPDTXCHAN 4
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1E
0
ADCRATE[2:0]
0
ADCHPD ADCOSR AMUTEALL AMUTER
TXVAL_
TXVAL_
TXVAL_
REAL_
SF1
SF0
OVWR
THROUGH
CHSTMODE[1:0]
DEEMPH[2:0]
AMUTEL
OVWCHAN
TXSRC[1:0]
CPY_N
AUDIO_N CON/PRO
101000000
000000010
1F
0
20
0
21
0
CHNUM2[1:0]
CHNUM1[1:0]
SRCNUM[3:0]
000000000
22
0
0
CLKACU[1:0]
FREQ[3:0]
000110001
CATCODE[7:0]
0
000000000
000000000
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WM8581
Production Data
R35
SPDTXCHAN 5
23
0
ORGSAMP[3:0]
R36
SPDMODE
24
0
R37
INTMASK
25
R38
GPO1
26
FILLMODE
GPO2OP[3:0]
R39
GPO2
27
ALWAYSVALID
GPO4OP[3:0]
GPO30P[3:0]
000110010
R40
GPO3
28
0
GPO6OP[3:0]
GPO5OP[3:0]
001010100
0
WL_MASK
1
TXWL[2:0]
1
1
RXINSEL[1:0]
MAXWL
000001011
SPDIFIN1MODE
000111001
MASK[8:0]
000000000
GPO1OP[3:0]
000010000
R41
GPO4
29
0
0
1
1
1
R42
Reserved
2A
0
1
0
0
1
R43
INTSTAT
2B
Error Flag Interupt Status Register
Read-only
R44
SPDRXCHAN 1
2C
Channel Status Register 1
Read-only
R45
SPDRXCHAN 2
2D
Channel Status Register 2
Read-only
R46
SPDRXCHAN 3
2E
Channel Status Register 3
Read-only
R47
SPDRXCHAN 4
2F
Channel Status Register 4
Read-only
R48
SPDRXCHAN 5
30
Channel Status Register 5
Read-only
R49
SPDSTAT
31
S/PDIF Status Register
Read-only
R50
PWRDN 1
32
0
0
ALLDACPD
R51
PWRDN 2
33
0
0
0
R52
READBACK
34
0
0
0
R53
RESET
35
GPO70P[3:0]
1
0
DACPD[3:0]
SPDIFRXD SPDIFTXD SPDIFPD
0
READEN
CONTREAD
PLLBPD
001110110
0
0
010011000
ADCPD
PWDN
001111110
PLLAPD
OSCPD
000111110
READMUX[2:0]
000000000
RESET
n/a
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).
Value K is one 22-digit binary number spread over registers R0,
R1 and R2 as shown.
R1
PLLA 2/
DEVID2
01h
8:0
PLLA_K[17:9]
101111110
R2
PLLA 3/
DEVREV
02h
3:0
PLLA_K[21:18]
1101
Reading from these registers will return the device ID.
R0 returns 10000001 = 81h
R1 returns 10000101 = 85h
Device ID readback is not possible in continuous readback mode
(CONTREAD=1).
7:4
PLLA_N[3:0]
0111
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)
Note: PRESCALE_A must be set to the same value as
PRESCALE_B in PLL S/PDIF receiver mode.
1
POSTSCALE_A
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 51.
PLL User Mode
Used in conjunction with the FREQMODE_x bits. Refer to Table
50.
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.
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PD, Rev 4.7, March 2009
80
WM8581
Production Data
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
50.
R4
PLLB 1
04h
8:0
PLLB_K[8:0]
100100001
R5
PLLB 2
05h
8:0
PLLB_K[17:9]
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.
R6
PLLB 3
06h
R7
PLLB 4
07h
R8
CLKSEL
08h
3:0
PLLB_K[21:18]
1101
7:4
PLLB_N[3:0]
0111
0
PRESCALE_B
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.
1
POSTSCALE_B
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 51.
PLL User Mode
Used in conjunction with the FREQMODE_x bits. Refer to Table
50.
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
50.
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
8:7
CLKOUTSRC
11
CLKOUT pin source
00 = No Output (tristate)
01 = Output – Source PLLACLK
10 = Output – Source PLLBCLK
11 = Output – Source OSCCLK
1:0
DAC_CLKSEL
00
DAC clock source
00 = MCLK pin
01 = PLLACLK
10 = PLLBCLK
11 = MCLK pin
w
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.
PD, Rev 4.7, March 2009
81
WM8581
REGISTER
ADDRESS
R9
PAIF 1
09h
Production Data
BIT
LABEL
DEFAULT
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
1 = auto-configuration disabled, clock configuration follows
relevant CLKSEL bits in R8 to R11.
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
00
Master Mode BCLK Rate
00 = 64 BCLKs per LRCLK
01 = 32 BCLKs per LRCLK
10 = 16 BCLKs per LRCLK
11 = BCLK = System Clock
4:3 PAIFRX_BCLKSEL
[1:0]
R10
PAIF 2
0Ah
DESCRIPTION
5
PAIFRXMS
0
PAIF Receiver Master/Slave Mode Select
0 = Slave Mode
1 = Master Mode
7:6
PAIFRXMS_
CLKSEL
00
PAIF Receiver Master Mode clock source
00 = MCLK pin
01 = PLLACLK
10 = PLLBCLK
11 = MCLK pin
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
00
Master Mode BCLKRate
00 = 64 BCLKs per LRCLK
01 = 32 BCLKs per LRCLK
10 = 16 BCLKs per LRCLK
11 = BCLK = System Clock
0
PAIF Transmitter Master/Slave Mode Select:
0 = Slave Mode
1 = Master Mode
4:3 PAIFTX_BCLKSEL
[1:0]
5
PAIFTXMS
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WM8581
Production Data
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
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
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)
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
6
DACOSR
0
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
R12
PAIF 3
0Ch
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DESCRIPTION
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83
WM8581
Production Data
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
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/I S 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
1:0
SAIFFMT
[1:0]
10
SAIF Audio Data Format Select
11: DSP Format
10: I2S Format
01: Left justified
00: Right justified
3:2
SAIFWL
[1:0]
10
SAIF Audio Data Word Length
11: 32 bits (see Note)
10: 24 bits
01: 20 bits
00: 16 bits
4
SAIFLRP
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
SAIFBCP
0
SAIF BCLK polarity
0 = BCLK not inverted
1 = BCLK inverted
6
SAIF_EN
0
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
1:0
DAC1SEL
[1:0]
00
3:2
DAC2SEL
[1:0]
01
DAC digital input select
00 = DAC takes data from DIN1
01 = DAC takes data from DIN2
10 = DAC takes data from DIN3
R14
SAIF 2
0Eh
R15
DAC
CONTROL
1
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DESCRIPTION
2
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84
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Production Data
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
0Fh
5:4
DAC3SEL
[1:0]
10
7:6
DAC4SEL
[1:0]
11
8
RX2DAC_MODE
0
3:0
PL[3:0]
1001
R16
DAC
CONTROL
2
10h
R17
DAC
CONTROL
3
11h
6:4
DZFM[2:0]
000
7
IZD
0
3:0
DEEMP[3:0]
0000
4
DEEMPALL
0
w
DESCRIPTION
11 = DAC takes data from DIN4
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
PL[3:0]
Left O/P
0000
Mute
Right O/P
Mute
0001
Left
Mute
0010
Right
Mute
0011
(L+R)/2
Mute
0100
Mute
Left
0101
Left
Left
0110
Right
Left
0111
(L+R)/2
Left
1000
Mute
Right
1001
Left
Right
1010
Right
Right
1011
(L+R)/2
Right
1100
Mute
(L+R)/2
1101
Left
(L+R)/2
1110
Right
(L+R)/2
1111
(L+R)/2
(L+R)/2
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
110 –- ZFLAG = 0
111 –- ZFLAG = 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
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
0 = De-emphasis controlled by DEEMP[3:0]
1 = De-emphasis enabled on all DACs
PD, Rev 4.7, March 2009
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Production Data
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
R18
DAC
CONTROL
4
12h
7:0
PHASE [7:0]
11111111
R19
DAC
CONTROL
5
13h
3:0
DMUTE[3:0]
0000
4
MUTEALL
0
DAC channel master soft mute. Mutes all DAC channels
0 = disable soft-mute on all DACs
1 = enable soft-mute on all DACs
5
DZCEN
0
DAC Digital Volume Zero Cross Enable
0 = Zero Cross detect disabled
1 = Zero Cross detect enabled
6
DACATC
0
Attenuator Control
0 = All DACs use attenuations as programmed.
1 = Right channel DACs use corresponding left DAC attenuations
7
MPDENB
0
MUTE pin decode enable
0 = MUTE activates soft-mute on DAC selected by DZFM
1 = MUTE activates softmute on all DACs
7:0
LDA1[7:0]
11111111
(0dB)
Digital Attenuation control for DAC1 Left Channel (DACL1) in
0.5dB steps. See Table 23
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
7:0
RDA1[7:0]
11111111
(0dB)
Digital Attenuation control for DAC1 Right Channel (DACR1) in
0.5dB steps. See Table 23
8
UPDATE
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
7:0
LDA2[7:0]
11111111
(0dB)
Digital Attenuation control for DAC2 Left Channel (DACL2) in
0.5dB steps. See Table 23
8
UPDATE
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
7:0
RDA2[7:0]
11111111
(0dB)
Digital Attenuation control for DAC2 Right Channel (DACR2) in
0.5dB steps. See Table 23
8
UPDATE
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
7:0
LDA3[7:0]
11111111
(0dB)
Digital Attenuation control for DAC3 Left Channel (DACL3) in
0.5dB steps. See Table 23
8
UPDATE
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
R20
DIGITAL
ATTENUATION
DACL 1
14h
R21
DIGITAL
ATTENUATION
DACR 1
15h
R22
DIGITAL
ATTENUATION
DACL 2
16h
R23
DIGITAL
ATTENUATION
DACR 2
17h
R24
DIGITAL
ATTENUATION
DACL 3
18h
w
DESCRIPTION
Controls phase of DAC outputs
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
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
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Production Data
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
R25
7:0
RDA3[7:0]
11111111
(0dB)
Digital Attenuation control for DAC3 Right Channel (DACR3) in
0.5dB steps. See Table 23
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
7:0
LDA4[7:0]
11111111
(0dB)
Digital Attenuation control for DAC4 Left Channel (DACL4) in
0.5dB steps. See Table 23
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
7:0
RDA4[7:0]
11111111
(0dB)
Digital Attenuation control for DAC4 Right Channel (DACR4) in
0.5dB steps. See Table 23
8
UPDATE
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
7:0
MASTDA[7:0]
11111111
(0dB)
Digital Attenuation control for all DAC channels in 0.5dB steps.
See Table 23
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
0
AMUTEL
0
ADC Mute select
0 : Normal Operation
1: mute ADC left
1
AMUTER
0
ADC Mute select
0 : Normal Operation
1: mute ADC right
2
AMUTEALL
0
ADC Mute select
0 : Normal Operation
1: mute both ADC channels
3
ADCOSR
0
ADC oversample rate select
0 = 128/64 x oversampling
1 = 64/32 x oversampling
4
ADCHPD
0
ADC high-pass filter disable:
0 = high-pass filter enabled
1 = high-pass filter disabled
7:5
ADCRATE[2:0]
010
DIGITAL
ATTENUATION
DACR 3
19h
R26
DIGITAL
ATTENUATION
DACL 4
1Ah
R27
DIGITAL
ATTENUATION
DACR 4
1Bh
R28
MASTER
DIGITAL
ATTENUATION
1Ch
R29
ADC
CONTROL
1
1Dh
DESCRIPTION
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
R30
8
VMIDSEL
1
VMID Impedance Selection
0 = High impedance, power saving
1 = Low impedance, fast power-on
1:0
TXSRC[1:0]
10
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
SPDTXCHAN 0
1Eh
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REGISTER
ADDRESS
R31
Production Data
BIT
LABEL
DEFAULT
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.
3
REAL_
THROUGH
0
S/PDIF Through Mode Control
0 = SPDIFOP pin sources output of S/PDIF Transmitter
1 = SPDIFOP pins sources output of S/PDIF IN Mux
4
TXVAL_OVWR
0
S/PDIF Transmitter Validity Overwrite Mode
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
TXVAL_SF0
0
Overwrite Mode S/PDIF Transmitter Validity Sub-Frame 0
0 = transmit validity = 0
1 = transmit validity = 1
6
TXVAL_SF1
0
Overwrite Mode S/PDIF Transmitter Validity Sub-Frame 1
0 = transmit validity = 0
1 = transmit validity = 1
0
CON/PRO
0
0 = Consumer Mode
1 = Professional Mode (not supported by WM8581)
1
AUDIO_N
0
0 = S/PDIF transmitted data is audio PCM.
1 = S/PDIF transmitted data is not audio PCM.
2
CPY_N
0
0 = Transmitted data has copyright asserted.
1 = Transmitted data has no copyright assertion.
5:3
DEEMPH[2:0]
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]
00
00 = Only valid mode for consumer applications.
7:0
CATCODE
[7:0]
00000000
3:0
SRCNUM
[3:0]
0000
5:4
CHNUM1[1:0]
00
SPDTXCHAN 1
1Fh
R32
SPDTXCHAN 2
DESCRIPTION
Category Code. Refer to S/PDIF specification for details.
00h indicates “general” mode
20h
R33
SPDTXCHAN 3
21h
7:6
R34
3:0
CHNUM2[1:0]
FREQ[3:0]
SPDTXCHAN 4
w
00
0001
Source Number. No definitions are attached to data.
Channel Number for Subframe 1
CHNUM1
Channel Status Bits[21:20]
00
0000 = Do not use channel number
01
0001 = Send to Left Channel
10
0010 = Send to Right Channel
11
0000 = Do not use channel number
Channel Number for Subframe 2
CHNUM2
Channel Status Bits[23:22]
00
0000 = Do not use channel number
01
0001 = Send to Left Channel
10
0010 = Send to Right Channel
11
0000 = Do not use channel number
Sampling Frequency. See S/PDIF specification for details.
0001 = Sampling Frequency not indicated.
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REGISTER
ADDRESS
BIT
LABEL
DEFAULT
22h
5:4
CLKACU[1:0]
11
Clock Accuracy of Generated clock.
00 = Level II
01 = Level I
10 = Level III
11 = Interface frame rate not matched to sampling frequency.
R35
0
MAXWL
1
Maximum Audio sample word length
0 = 20 bits
1 = 24 bits
3:1
TXWL[2:0]
101
SPDTXCHAN 5
23h
DESCRIPTION
Audio Sample Word Length.
000 = Word Length Not Indicated
TXWL[2:0]
MAXWL==1
MAXWL==
0
001
20 bits
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
R36
SPDMODE
24h
7:4
ORGSAMP
[3:0]
0000
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 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
0
R37
INTMASK
25h
8:0
MASK[8:0]
000000000
R38
3:0
GPO1OP[3:0]
0000
w
Original Sampling Frequency. See S/PDIF specification for details.
0000 = original sampling frequency not indicated
S/PDIF Receiver Word Length Truncation Mask
0 = disabled, data word is truncated as described in Table 66.
1 = enabled, data word is not truncated.
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
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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.
3:0
GPO3OP[3:0]
0010
7:4
GPO4OP[3:0]
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
R39
GPO2
27h
R40
GPO3
28h
3:0
GPO5OP[3:0]
0100
7:4
GPO6OP[3:0]
0101
w
Automatic Error Handling Configuration for INVALID Flag
0 = INVALID flag automatic error handling enabled.
1 = INVALID flag automatic error handling disabled.
0000 = INT_N
0001 = V
0010 = U
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REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
R41
GPO4
29h
3:0
GPO7OP[3:0]
0110
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
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
1
INT_INVALID
-
INVALID flag interrupt signal
0 = INT_N not caused by INVALID flag
1 = INT_N caused by INVALID flag
2
INT_CSUD
-
CSUD flag interrupt signal
0 = INT_N not caused by CSUD flag
1 = INT_N caused by CSUD flag
3
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
4
UPD_NON_AUDIO
-
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
5
UPD_CPY_N
-
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
6
UPD_DEEMPH
-
DEEMPH update signal
0 = INT_N not caused by update to DEEMPH flag
1 = INT_N caused by update to DEEMPH flag
7
UPD_REC_FREQ
-
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
CON/PRO
-
0 = Consumer Mode
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.
2
CPY_N
-
0 = Copyright is asserted for this data.
1 = Copyright is not asserted for this data.
3
DEEMPH
-
0 = Recovered S/PDIF data has no pre-emphasis.
1 = Recovered S/PDIF data has pre-emphasis.
5:4
Reserved
-
Reserved for additional de-emphasis modes.
7:6
CHSTMODE
[1:0]
-
00 = Only valid mode for consumer applications.
R44
SPDRXCHAN 1
2C
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REGISTER
ADDRESS
BIT
LABEL
DEFAULT
R45
7:0
CATCODE
[7:0]
-
Category Code. Refer to S/PDIF specification for details.
00h indicates “general” mode.
3:0
SRCNUM
[3:0]
-
Indicates number of S/PDIF source.
5:4
CHNUM1[1:0]
-
Channel number for sub-frame 1.
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
7:6
CHNUM2[1:0]
3:0
FREQ[3:0]
-
Sampling Frequency. See S/PDIF specification for details.
0001 = Sampling Frequency not indicated.
2Fh
5:4
CLKACU[1:0]
-
Clock Accuracy of received clock.
00 = Level II
01 = Level I
10 = Level III
11 = Interface frame rate not matched to sampling frequency.
R48
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
SPDRXCHAN 2
DESCRIPTION
2Dh
R46
SPDRXCHAN 3
2Eh
R47
Channel number for sub-frame 2.
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
SPDRXCHAN 4
SPDRXCHAN 5
30h
RXWL[2:0]
MAXWL==1
MAXWL==
0
001
20 bits
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.
R49
SPDSTAT
31h
7:4
ORGSAMP
[3:0]
-
Original Sampling Frequency. See S/PDIF specification for details.
0000 = original sampling frequency not indicated
0
AUDIO_N
-
Recovered Channel Status bit-1.
0 = Data word represents audio PCM samples.
1 = Data word does not represent audio PCM samples.
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
CPY_N
-
Recovered Channel Status bit-2.
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.
3
DEEMPH
-
Recovered Channel Status bit-3
0 = Recovered S/PDIF data has no pre-emphasis.
1 = Recovered S/PDIF data has pre-emphasis
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REGISTER
ADDRESS
R50
PWRDN 1
32h
R51
PWRDN 2
33h
R52
READBACK
34h
BIT
LABEL
DEFAULT
5:4
REC_FREQ
[1:0]
-
Indicates recovered S/PDIF clock frequency:
00 = Invalid
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.
0
PWDN
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
1
ADCPD
1
ADC powerdown:
0 = ADC enabled
1 = ADC disabled
5:2
DACPD[3:0]
1111
6
ALLDACPD
1
Overrides DACPD[3:0]
0 = DACs under control of DACPD[3:0]
1= All DACs are disabled.
0
OSCPD
0
OSC power down
0 = OSC enabled
1 = OSC disabled
1
PLLAPD
1
0 = PLLA enabled
1 = PLLA disabled
2
PLLBPD
1
0 = PLLB enable
1 = PLLB disable
3
SPDIFPD
1
S/PDIF Clock Recovery PowerDown
0 = S/PDIF enabled
1 = S/PDIF disabled
4
SPDIFTXD
1
S/PDIF Transmitter powerdown
0 = S/PDIF Transmitter enabled
1 = S/PDIF Transmitter disabled
5
SPDIFRXD
1
S/PDIF Receiver powerdown
0 = S/PDIF Receiver enabled
1 = S/PDIF Receiver disabled
2:0
READMUX
[2:0]
000
3
CONTREAD
0
w
DESCRIPTION
DAC powerdowns (0 = DAC enabled, 1 = DAC disabled)
DACPD[0] = DAC1
DACPD[1] = DAC2
DACPD[2] = DAC3
DACPD[3] = DAC4
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.
0 = Continuous read-back mode disabled
1 = Continuous read-back mode enabled
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REGISTER
ADDRESS
R53
RESET
35h
Production Data
BIT
LABEL
DEFAULT
4
READEN
0
8:0
RESET
n/a
w
DESCRIPTION
Read-back mode enable.
0 = read-back mode disabled
1 = read-back mode enabled
Writing to this register will apply a reset to the device registers.
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DIGITAL FILTER CHARACTERISTICS
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
ADC Filter
±0.01 dB
Passband
0
0.4535fs
-6dB
0.5fs
±0.01
Passband ripple
Stopband
dB
0.5465fs
Stopband Attenuation
f > 0.5465fs
-65
dB
DAC Filter
±0.05 dB
Passband
0.444fs
-3dB
0.487fs
±0.05
Passband ripple
Stopband
dB
0.555fs
Stopband Attenuation
f > 0.555fs
-60
dB
Table 82 Digital Filter Characteristics
DAC FILTER RESPONSES
0.2
0
0.15
-20
-40
Response (dB)
Response (dB)
0.1
-60
0.05
0
-0.05
-80
-0.1
-100
-0.15
-120
-0.2
0
0.5
1
1.5
Frequency (Fs)
2
2.5
3
Figure 43 DAC Digital Filter Frequency Response
– 44.1, 48 and 96KHz
0
0.05
0.1
0.15
0.2
0.25
0.3
Frequency (Fs)
0.35
0.4
0.45
0.5
Figure 44 DAC Digital Filter Ripple –44.1, 48 and 96kHz
0.2
0
0
-0.2
Response (dB)
Response (dB)
-20
-40
-0.4
-0.6
-60
-0.8
-80
-1
0
0.2
0.4
0.6
Frequency (Fs)
0.8
Figure 45 DAC Digital Filter Frequency Response
– 192KHz
w
1
0
0.05
0.1
0.15
0.2
0.25
0.3
Frequency (Fs)
0.35
0.4
0.45
0.5
Figure 46 DAC Digital Filter Ripple – 192kHz
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DIGITAL DE-EMPHASIS CHARACTERISTICS
0
0.4
0.3
-2
Response (dB)
Response (dB)
0.2
-4
-6
0.1
0
-0.1
-0.2
-8
-0.3
-10
-0.4
0
5
10
Frequency (kHz)
15
20
0
Figure 47 De-Emphasis Frequency Response (44.1KHz)
5
10
Frequency (kHz)
15
20
Figure 48 De-Emphasis Error (44.1KHz)
0
1
0.8
-2
0.6
Response (dB)
Response (dB)
0.4
-4
-6
0.2
0
-0.2
-0.4
-8
-0.6
-0.8
-10
-1
0
5
10
15
Frequency (kHz)
20
0
Figure 49 De-Emphasis Frequency Response (48kHz)
5
10
15
Frequency (kHz)
20
Figure 50 De-Emphasis Error (48kHz)
ADC FILTER RESPONSES
0.02
0
0.015
0.01
Response (dB)
Response (dB)
-20
-40
0.005
0
-0.005
-60
-0.01
-0.015
-80
-0.02
0
0.5
1
1.5
Frequency (Fs)
2
2.5
Figure 51 ADC Digital Filter Frequency Response
w
3
0
0.05
0.1
0.15
0.2
0.25
0.3
Frequency (Fs)
0.35
0.4
0.45
0.5
Figure 52 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.
H(z) =
1 - z-1
1 - 0.9995z-1
Response (dB)
0
-5
-10
-15
0
0.0005
0.001
Frequency (Fs)
0.0015
0.002
Figure 53 ADC Highpass Filter Response
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APPLICATIONS INFORMATION
RECOMMENDED EXTERNAL COMPONENTS
Figure 54 Recommended–External Components – Hardware
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WM8581
Figure 55 Recommended–External Components – Software
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PACKAGE DIMENSIONS
FT: 48 PIN TQFP (7 x 7 x 1.0 mm)
b
DM004.C
e
36
25
37
24
E1
48
E
13
1
12
Θ
D1
c
D
L
A A2
A1
-Cccc C
Symbols
A
A1
A2
b
c
D
D1
E
E1
e
L
Θ
ccc
REF:
SEATING PLANE
Dimensions
(mm)
MIN
NOM
MAX
--------1.20
0.05
----0.15
0.95
1.00
1.05
0.17
0.22
0.27
0.09
----0.20
9.00 BSC
7.00 BSC
9.00 BSC
7.00 BSC
0.50 BSC
0.45
0.60
0.75
o
o
o
3.5
7
0
Tolerances of Form and Position
0.08
JEDEC.95, MS-026
NOTES:
A. ALL LINEAR DIMENSIONS ARE IN MILLIMETERS.
B. THIS DRAWING IS SUBJECT TO CHANGE WITHOUT NOTICE.
C. BODY DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSION, NOT TO EXCEED 0.25MM.
D. MEETS JEDEC.95 MS-026, VARIATION = ABC. REFER TO THIS SPECIFICATION FOR FURTHER DETAILS.
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WM8581
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.
The product described in this datasheet incorporates clocking technology that has been licensed from Sonopsis Ltd. which is
protected by patents including EP1611684B1 and US7495515. Additional patent applications are pending.
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 :: [email protected]
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