WM8777
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REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
Received Channel status bit 1
(51h)
0
AUDIO_N
S/PDIF Status
Register
(read-only)
0 = Data word represents audio PCM samples.
1 = Data word does not represent audio PCM samples.
1
2
PCM_N
CPY_N
Detects non-audio data from a 96-bit sync code, as
defined in IEC-61937.
0 = Sync code not detected.
1 = Sync code detected – received data is not audio
PCM.
Recovered S/PDIF 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.
4:3
SPDIF_MODE
S/PDIF frequency mode.
00: Mode not supported
01: 88-96KHz
10: 44-48KHz
11: 32KHz
Table 46 S/PDIF Rx Status Register
Should the incoming S/PDIF sub-frame contain a PARITY error or a BIP error, it is assumed the sub-
frame has become corrupted. These errors would normally be flagged, but if the error bits have been
masked, the WM8777 will instead overwrite the recovered frame (i.e. both sub-frames) with either
all-zeros or the last data sample (depending on how FILLMODE has been set). When the flags are
unmasked and an error is detected, the data is allowed to pass, albeit still corrupted.
Similarly, if VALIDITY is detected as 1, it is assumed the data within the S/PDIF frame is invalid. If
VALIDITY is masked, then data is overwritten depending on FILLMODE, else VALIDITY is flagged
and the (invalid) data is allowed to pass. (Note1: ALWAYSVALID must be set to 0, else the
recovered VALIDITY bit will be ignored). (Note 2: For the S/PDIF Receiver to S/PDIF transmitter
path, only masked VALIDITY errors will cause data to be overwritten – PARITY and BIP errors have
no effect).
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
(49h)
7:0
MASK[7:0]
0000000
When a lag is masked, it does not update the Error
Register or contribute to the interrupt pulse. 0 =
unmask, 1 = mask.
S/PDIF
Receiver
Error Mask
MASK[0] = mask control for UNLOCK
MASK[1] = mask control for VALIDITY
MASK[2] = mask control for PARITYERR
MASK[3] = mask control for BIP
MASK[4] = mask control for AUDIO_N
MASK[5] = mask control for PCM_N
MASK[6] = mask control for CPY_N
MASK[7] = mask control for SPDIF_MODE
(40h)
6
7
FILLMODE
Determines what SPDIF_RX should do if the validity bit
indicates invalid data:
0
0
S/PDIF
Receiver
Input Selector
0 = Data from SPDIF_RX remains static at last valid
sample.
1 = Data from SPDIF_RX is output as all zeros.
Used to override the recovered validity bit.
0 = Use validity bit.
ALWAYSVALID
1 = Ignore validity bit.
Table 47 S/PDIF Rx Error Mask Register
PP Rev 1.94 November 2004
54
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WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
