AD1985 Analog Devices, AD1985 Datasheet - Page 24

• Manufacturer Part Number: AD1985
• Description: AC'97 2.3 Soundmax Codec W/jack Sensing
• Manufacturer: Analog Devices

AD1985
General Purpose Register (Index 0x20)
Reg Num
0x20
LPBK
MS
MIX
DRSS[1:0]
Name
General-Purpose
Loopback Control. This bit enables the digital internal loopback from the ADC to the Front DAC. This feature is
normally used for test and troubleshooting. See LBKS bit in Register 0x74 for changing the loopback path to use the
Surround or Center/LFE DACs.
MIC Select. Selects MIC input into the Record Selector input and also selects the input to the analog mixer.
Note:
The following chart shows which of the codec I/O pins is used for the microphone source from the various settings
of the microphone control bits.
OMS
0
0
0
0
1
1
1
1
Mono Output Select. Selects mono output audio source.
0 = Mixer output. Default.
1 = Selected MIC channel (selected channel is unaffected by 2CMIC setting).
MIX
0
1
1
1
1
Double Rate Slot Select. The DRSS bits specify the slots for the n + 1 sample outputs. PCM L (n + 1) and PCM R (n + 1)
data are by default provided in output slots 10 and 11.
00: PCM L, R n + 1 data is on slots 10, 11 (reset default).
01: PCM L, R n + 1 data is on slots 7, 8.
10: Reserved.
11: Reserved.
See the 2CMIC (Bit D7 Reg. 0x76) to enable simultaneous dual microphone recording.
See the OMS (Bit D9 Reg. 0x74) to enable output line sharing for the Microphone inputs.
2CMIC
0
0
1
1
0
0
1
1
OMS
X
0
0
1
1
D15 D14 D13 D12 D11
X
X
MS
0
1
0
1
0
1
0
1
MS
X
0
1
0
1
X
Left Channel
MIC 1 (mono)
MIC 2 (mono)
MIC 1 (stereo)
MIC 2 (stereo)
CENTER (mono)
LFE (mono)
CENTER (stereo)
LFE (stereo)
Mono Output
Mixer_mono (default)
MIC 1 (mono)
MIC 2 (mono)
CENTER (mono)
LFE (mono)
X
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DRSS1
D10
DRSS0
D9
MIX MS LPBK X
D8 D7
Right Channel
MIC 1 (mono)
MIC 2 (mono)
MIC 2 (stereo)
MIC 1 (stereo)
CENTER (mono)
LFE (mono)
LFE (stereo)
CENTER (stereo)
D6 D5 D4 D3 D2 D1 D0 Default
X
X
X
X
X
X
0x0000