cs4297 Cirrus Logic, Inc., cs4297 Datasheet - Page 17

• Manufacturer Part Number: cs4297
• Description: Crystalclear Soundfusion Audio Codec 97 Logic
• Manufacturer: Cirrus Logic, Inc.

DS242F5
Slot 2: AC’97 Register Write Data
Slot 2 indicates the Register Data of the current frame’s register write access.The 20 bits of this slot are
defined as:
WD15 - WD0 - Bits 19-4 contain the 16-bit value to be written to the register. Bits 3-0 are ignored, but
should always be ‘cleared’. If the access is a read, this slot is ignored. The data in Slot 2 will only be valid
when the Slot Valid bit 13 of Slot 0 (F2) corresponding to Slot 2 is ‘set’.
NOTE: For any write to an AC’97 Register, the write is defined to be an ‘atomic’ access. This means that
when the slot valid bit for Slot 1 is ‘set’, the slot valid bit for Slot 2 should always be ‘set’ during the same
audio frame. No write access may be split across 2 frames.
Slot 3: Left Channel PCM Playback Data
Slot 3 contains the left channel data. The 20 bits of this slot are defined as:
LP17 - LP0 - This is the 18-bit PCM playback 2’s compliment data for the left channel DAC in the
CS4297. The PCM playback data will be taken from the most significant 18 of the 20 bits in the slot. The
least significant 2 bits will be ignored. Any PCM data from the AC’97 Controller that is not at least 18-
bits should be left justified in Slot 3 and dithered or zero-padded in the unused bit positions.
Slot 4: Right Channel PCM Playback Data
Slot 4 contains the right channel data. The 20 bits of this slot are defined as:
RP17 - RP0 - This is the 18-bit PCM playback 2’s compliment data for the right channel DAC in the
CS4297. The PCM playback data will be taken from the most significant 18 of the 20 bits in the slot. The
least significant 2 bits will be ignored. Any PCM data from the AC’97 Controller that is not at least 18-
bits should be left justified in Slot 4 and dithered or zero-padded in the unused bit positions.
WD15 WD14 WD13 WD12 WD11 WD10 WD9 WD8 WD7 WD6 WD5 WD4 WD3 WD2 WD1 WD0
Bit 19 18
Bit 19 18
RP17 RP16 RP15 RP14 RP13 RP12 RP11 RP10 RP9 RP8 RP7 RP6 RP5 RP4 RP3 RP2 RP1 RP0
CS4297
CrystalClear™ SoundFusion™ Audio Codec ’97
Bit 19
LP17 LP16 LP15 LP14 LP13 LP12 LP11 LP10 LP9 LP8 LP7 LP6 LP5 LP4 LP3 LP2 LP1 LP0
F56
F76
F36
F57
F77
F37
18
F58
F78
17
17
F38
17
F59
F79
16
16
F39
16
F60
F80
15
15
F40
15
F61
F81
14
14
F41
14
F62
F82
13
13
F42
13
F63
F83
12
12
F43
12
F64
F84
11
11
F44
11
F65
F85
10
10
F45
10
F66
F86
9
9
F46
9
F67
F87
8
8
F47
8
F68
F88
7
7
F48
F69
F89
7
6
6
F49
F70
F90
6
5
5
F50
F71
F91
4
4
5
F72
F92
F51 F52 F53 F54 F55
3
3
4
F73
F93
3
2
2
Reserved
2
F74
F94
Reserved
Reserved
1
1
1
F75
F95
0
0
0
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