wm9704q Wolfson Microelectronics plc, wm9704q Datasheet - Page 26

• Manufacturer Part Number: wm9704q
• Description: 4-channel Surround Sound Codec
• Manufacturer: Wolfson Microelectronics plc

WM9704Q
WOLFSON MICROELECTRONICS LTD
RECORD SELECT CONTROL REGISTER (INDEX 1Ah)
Used to select the record source independently for right and left (see Table 14). The default value is
0000h, which corresponds to Mic in.
Table 14 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 15 Record Gain Register Function
GENERAL PURPOSE REGISTER (INDEX 20h)
This register is used to control several miscellaneous functions of the WM9704Q.
Below is a summary of each bit and its function. Only the MIX, MS and LPBK bits are supported by
the WM9704Q. 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 16 General Purpose Register Function
3D CONTROL REGISTER (INDEX 22h)
This register is used to control the centre and/or depth of the 3D stereo enhancement function built
into of the AC ‘97 component. Only the depth bits DP0 to 3 have effect in the WM9704Q.
SR2 TO SR0
MUTE
0
0
1
RLBK
LPBK
LLBK
POP
DP3…DP0
MIX
MS
BIT
ST
3D
LD
0
1
2
3
4
5
6
7
15
0
1
8
-
-
GX3...GX0
xxxxx
1111
0000
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
RIGHT RECORD SOURCE
Stereo mix (R)
Video in (R)
Line in (R)
Aux in (R)
Mono mix
CD in (R)
Phone
Mic
FUNCTION
+22.5dB gain
0dB gain
-
Typical value
dB gain
DEPTH
100%
0%
SL2 TO SL0
0
1
2
3
4
5
6
7
LEFT RECORD SOURCE
Stereo mix (L)
Video in (L)
PD Rev 2.3 January 2001
Yes, but fixed at 1
Line in (L)
Mono mix
Aux in (L)
CD in (L)
Phone
Mic
WM9704Q
SUPPORT
Production Data
Yes
Yes
Yes
Yes
No
No
No
No
dB.
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