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WM8581
w
PP Rev 1.0 March 2006
65
ALWAYSVALID must be set to 0, else the INVALID flag will be ignored. For the S/PDIF Receiver to
S/PDIF transmitter path, only masked INVALID flags will cause data to be overwritten – TRANS_ERR
flags have no effect.
REGISTER
ADDRESS
BIT LABEL DEFAULT
DESCRIPTION
R38
GPO1
26h
8
FILLMODE
0
Determines what S/PDIF Receiver should do with
corrupted or invalid data:
0 = Data from S/PDIF Receiver remains static at last
valid sample.
1 = Data from S/PDIF Receiver is output as all zeros.
R39
GPO2
27h
8
ALWAYSVALID
0
Used to ignore the INVALID flag. See Table 64.
0 = Use INVALID flag.
1 = Ignore INVALID flag.
Table 63 S/PDIF Receiver Error Handling Registers
MASK
ALWAYSVALID
DATA OVERWRITE
INTB ASSERT
0 0
No
Yes
0 1
No
No
1 0
Yes
No
1 1
No
No
Table 64 Data Overwrite / INTB Assert Criteria
NON-AUDIO DETECTION
Non-Audio data is indicated by the AUDIO_N and PCM_N flags. AUDIO_N is recovered from the
Channel Status block. PCM_N is set on detection of the 96-bit IEC-61937 non-audio data sync code,
embedded in the data section of the S/PDIF frame. If DAC1 is sourcing the S/PDIF Receiver and
either the AUDIO_N or PCM_N flags are asserted, DAC1 is automatically muted using the softmute
feature. As described above, any change of AUDIO_N or PCM_N status will cause an INTB 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 65. The
GPO pins can be used to output status data decoded by the S/PDIF receiver. These same pins may be used
as S/PDIF inputs as described in Table 53.
REGISTER
ADDRESS
BIT LABEL DEFAULT
DESCRIPTION
3:0 GPO1OP[3:0]
0000
R38
GPO1
26h
7:4 GPO2OP[3:0]
0001
3:0 GPO3OP[3:0]
0010
R39
GPO2
27h
7:4 GPO4OP[3:0]
0011
3:0 GPO5OP[3:0]
0100
R40
GPO3
28h
7:4 GPO6OP[3:0]
0101
0000 = INTB
0001 = V
0010 = U
0011 = C
0100 = P
0101 = SFRM_CLK
0110 = 192BLK
0111 = UNLOCK
1000 = CSUD