WM9704CFT/V Wolfson Microelectronics plc, WM9704CFT/V Datasheet - Page 26

• Manufacturer Part Number: WM9704CFT/V
• Description: AMC97 Audio and Modem Codec
• Manufacturer: Wolfson Microelectronics plc

WM9704M
WOLFSON MICROELECTRONICS LTD
Table 12 Mixer Gain Control Register Function
RECORD SELECT CONTROL REGISTER (INDEX 1AH)
Used to select the record source independently for right and left (see Table 13). The default value is
0000h, which corresponds to Mic in.
Table 13 Record Select Register Function
RECORD GAIN REGISTERS (INDEX 1CH AND 1EH)
1Ch is for the stereo input and 1Eh is for the optional special purpose correlated audio Mic channel.
Each step corresponds to 1.5dB. 22.5dB corresponds to 0F0Fh and 000Fh respectively. The MSB of
the register is the mute bit. When this bit is set to 1, the level for that channel(s) is set at -
The default value is 8000h, which corresponds to 0dB gain with mute on.
Table 14 Record Gain Register Function
GENERAL PURPOSE REGISTER (INDEX 20H)
This register is used to control several miscellaneous functions of the WM9704M.
Below is a summary of each bit and its function. Only the MIX, MS and LPBK bits are supported by
the WM9704M. The MS bit controls the Mic selector. The LPBK bit enables loopback of the ADC
output to the DAC input without involving the AC-link, allowing for full system performance
measurements. The function default value is 8000h, which is all off.
Table 15 General Purpose Register Function
SR2 TO SR0
MUTE
MUTE
0
0
0
1
0
0
1
RLBK
LPBK
LLBK
POP
MIX
MS
0
1
2
3
4
5
6
7
BIT
ST
3D
LD
1111
0000
xxxxx
GX4...GX0
GX3...GX0
00000
01000
11111
xxxxx
RIGHT RECORD SOURCE
Mic
CD in (R)
Video in (R)
Aux in (R)
Line in (R)
Stereo mix (R)
Mono mix
Phone
FUNCTION
PCM out path and mute, 0 = pre-3D, 1 = post-3D
Simulated stereo enhancement, on/off 1 = on
3D stereo enhancement on/off, 1 = on
Loudness (bass boost) on/off, 1 = on
Local loop back - for modem, line codec
Remote loop back - for modem, line codec
Mono output select 0 = Mix, 1 = Mic
Mic select 0 = Mic1, 1 = Mic2
ADC/DAC loopback mode
FUNCTION
+12dB gain
0dB gain
-34.5dB gain
-
FUNCTION
+22.5dB gain
0dB gain
-
dB gain
dB gain
SL2 TO SL0
0
1
2
3
4
5
6
7
LEFT RECORD SOURCE
Mic
CD in (L)
Video in (L)
Aux in (L)
Line in (L)
Stereo mix (L)
Mono mix
Phone
Yes, but fixed at ‘1’
PD Rev 3.2 January 2001
WM9704M
SUPPORT
Production Data
Yes
Yes
Yes
Yes
No
No
No
No
dB.
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