CS4297 Datasheet, PDF (18/46 Pages) Cirrus Logic – CrystalClear SoundFusion Audio Codec 97

CS4297
CrystalClear™ SoundFusion™ Audio Codec ’97
AC-Link Audio Input Frame
An AC-Link serial data input frame uses the
SYNC, BIT_CLK, and SDATA_IN signals are
used. In the serial data input frame, data is passed
on the SDATA_IN pin FROM the CS4297 TO the
AC’97 Controller. The data format for the input
frame is very similar to the output frame. Synchro-
nization of the CS4297 to the AC’97 Controller is
performed in the same manner. Please refer to Fig-
ure 3 for the serial port timing waveform.
Slot 0: Serial Data Input Slot Tag Bits
The first slot, Slot 0, is a 16-bit slot which contains information about the validity of data for the remaining
12 slots. The 16 bits of this slot are defined as:
F0 F1 F2 F3 F4 F5 F6 F7 F8 F9 F10 F11 F12 F13 F14 F15
Bit 15 14 13 12 11 10
9
8
7
6
5
4
3
2
1
0
Codec Slot 1 Slot 2 Slot 3 Slot 4
Ready Valid Valid Valid Valid
Not Used
Codec Ready - Bit 15 indicates the readiness of the CS4297’s AC-Link and the AC’97 Control and Status
Registers. Immediately after a Cold Reset this bit will be returned to the AC’97 Controller ‘cleared’. Once
the CS4297’s clocks and voltages are stable, this bit will be set. Until the Codec Ready bit is ‘set’, no AC-
Link transactions should be attempted by the AC’97 Controller.
NOTE: This Codec Ready bit does not indicate readiness of the DACs, ADCs, Vref, or any other analog
function. Those must be checked in the Powerdown/Status Register by the AC’97 Controller. Any accesses
to the CS4297 while this bit is ‘cleared’ will be ignored.
Slot 1 Valid - Bit 14 indicates the validity of data in the serial data input Slot 1. If this bit is ‘set’, Slot 1
contains valid data. If this bit is ‘cleared’, Slot 1 should be ignored by the AC’97 Controller.
Slot 2 Valid - Bit 13 indicates the validity of data in the serial data input Slot 2. If this bit is ‘set’, Slot 2
contains valid data. If this bit is ‘cleared’, Slot 2 should be ignored by the AC’97 Controller.
Slot 3 Valid - Bit 12 indicates the validity of data in the serial data input Slot 3. If this bit is ‘set’, Slot 3
contains valid data. If this bit is ‘cleared’, Slot 3 should be ignored by the AC’97 Controller.
Slot 4 Valid - Bit 11 indicates the validity of data in the serial data input Slot 4. If this bit is ‘set’, Slot 4
contains valid data. If this bit is ‘cleared’, Slot 4 should be ignored by the AC’97 Controller.
Slot 0 bits 10 through 0 represent unimplemented data slots in the CS4297 and should be ignored by the
AC’97 Controller.
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DS242F5