CS4294SLASHCS4298 datasheet(31/66 Pages) CIRRUS

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CS4202

DS549PP2

4.13

Extended Audio Status/Control Register (Index 2Ah)

SPCV

S/PDIF Configuration Valid. This read-only bit indicates the status of the S/PDIF transmitter

subsystem, enabling the driver to determine if the currently programmed S/PDIF configura-

tion is supported. SPCV is always valid, independent of the S/PDIF enable bit status.

SPSA[1:0]

S/PDIF Slot Assignment. These bits control the mapping of output slots to the S/PDIF trans-

mitter. To satisfy AC ‘97 2.2 AMAP requirements, the default for these bits will depend on the

Codec ID as shown in Table 9 on page 30. See Table 8 on page 30 for all available Slot Map

settings.

SPDIF

Enable Sony/Philips Digital Interface. This bit enables S/PDIF data transmission on the

SPDIF_OUT pin. The SPDIF bit routes the left and right channel data from the AC ’97 con-

troller or from the ADC output to the S/PDIF transmitter block. The actual data routed to the

S/PDIF block are controlled through the configuration of the SPSA[1:0] bits and the ASPM bit

in the AC Mode Control Register (Index 5Eh).

VRA

Enable Variable Rate Audio. When ‘set’, the VRA bit allows access to the PCM Front DAC

Rate Register (Index 2Ch) and the PCM L/R ADC Rate Register (Index 32h). This bit must

be ‘set’ in order to use variable PCM playback or capture rates. The VRA bit also serves as

a powerdown for the DAC and ADC SRC blocks. Clearing VRA will reset the PCM Front DAC

Rate Register (Index 2Ch) and the PCM L/R ADC Rate Register (Index 32h) to their default

values. The SRC data path is flushed and the Slot Request bits for the currently active DAC

slots will be fixed at ‘0’.

Default

0410h

D15

D14

D13

D12

D11

D10

00000

SPCV

0000

SPSA1 SPSA0

SPDIF

VRA

CS4294/CS4298 데이터시트(PDF) 31 Page - Cirrus Logic