CS4297A datasheet(18/52 Pages) CIRRUS

18 / 52 page

CS4297A

3.3

AC-Link Protocol Violation - Loss of

SYNC

The CS4297A is designed to handle SYNC proto-

col violations. The following are situations where

the SYNC protocol has been violated:

•

The SYNC signal is not sampled high for exact-

ly 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 CS4297A will ‘clear’ the Codec Ready bit in

the serial data input frame until two valid frames

are detected. During this detection period, the

CS4297A will ignore all register reads and writes

and will discontinue the transmission of PCM cap-

ture data. In addition, if the LOSM bit in the Misc.

Crystal Control Register (Index 60h) is ‘set’ (de-

fault), the CS4297A will mute all analog outputs. If

the LOSM bit is ‘clear’, the analog outputs will not

be muted.

CS4297A Datasheet(PDF) 18 Page - Cirrus Logic