Cirrus Logic CS4202 - Manual (Page 33)

CS4202
DS549PP2 33
4.15 S/PDIF Control Register (Index 3Ah)
V Validity. The V bit is mapped to the V bit (bit 28) of every sub-frame. If this bit is ‘clear’, the
signal is suitable for conversion or processing.
DRS Double Rate S/PDIF. The DRS bit is mapped to bit 27 of the channel status block. This bit
controls support for optional higher sample rate transmission. The CS4202 does not support
double rate S/PDIF transmission, therefore DRS is a read-only bit and always returns ‘0’.
SPSR[1:0] S/PDIF Sample Rate. The SPSR[1:0] bits are mapped to bits 24 and 25 of the channel status
block. These bits control the S/PDIF transmitter clock rate. The CS4202 only supports trans-
mission at the standard 48 kHz rate, therefore SPSR[1:0] are read-only bits and always
return ‘10’.
L Generation Status. The L bit is mapped to bit 15 of the channel status block. For category
codes 001xxxx, 0111xxx and 100xxxx, a value of ‘0’ indicates original material and a value of
‘1’ indicates a copy of original material. For all other category codes the definition of the L bit
is reversed.
CC[6:0] Category Code. The CC[6:0] bits are mapped to bits 8-14 of the channel status block.
PRE Data Pre-emphasis. The PRE bit is mapped to bit 3 of the channel status block. If the PRE bit
is ‘set’, 50/15 µs filter pre-emphasis is indicated. If the bit is ‘clear’, no pre-emphasis is indi-
cated.
COPY Copyright. The COPY bit is mapped to bit 2 of the channel status block. If the COPY bit is ‘set’
copyright is not asserted and copying is permitted.
/AUDIO Audio / Non-Audio. The /AUDIO bit is mapped to bit 1 of the channel status block. If the
/AUDIO bit is ‘clear’, the data transmitted over S/PDIF is assumed to be digital audio. If the
/AUDIO bit is ‘set’, non-audio data is assumed.
PRO Professional/Consumer. The PRO bit is mapped to bit 0 of the channel status block. If the
PRO bit is ‘clear’, consumer use of the audio control block is indicated. If the bit is ‘set’, pro-
fessional use is indicated.
Default 2000h
For a further discussion of the proper use of the channel status bits see application note AN22: Overview of Digital
Audio Interface Data Structures [3]
D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0
V DRS SPSR1 SPSR0 L CC6 CC5 CC4 CC3 CC2 CC1 CC0 PRE COPY /AUDIO PRO