CS4294 datasheet(16/42 Pages) CIRRUS

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CS4294

DS326PP4

5.5.3 AC ’97 Register Reset

The third reset mode provides a register reset to the

CS4294. This is available only when the CS4294’s

AC-link is active and the Codec Ready bit is set.

The audio and extended codec subsections may be

reset independently. Any write to Reset (Index 00h)

write to Extended Codec Stat/Ctrl (Index 3Eh) reg-

ister will reset the Extended Codec subsection. See

the respective register descriptions for additional

information.

5.6

AC-Link Protocol Violation - Loss of

SYNC

The CS4294 is designed to handle SYNC protocol

violations. The following are situations where the

SYNC protocol has been violated:

• The SYNC signal is not sampled high for

exactly 16 BIT_CLK clock cycles at the

start of an audio frame.

• The SYNC signal is not sampled high on

the 256th BIT_CLK clock period after

the previous SYNC assertion.

• The SYNC signal goes active high before

the 256th BIT_CLK clock period after

the previous SYNC assertion.

Upon loss of synchronization with the Controller,

the Codec will mute all analog outputs and clear the

Codec Ready bit in the serial data input frame until

two valid frames are detected. During this detection

period, the Codec will ignore all register reads and

writes and will discontinue the transmission of

PCM capture data.

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