wm9704q Wolfson Microelectronics plc, wm9704q Datasheet - Page 29

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

Production Data
REVISION 2.1 REGISTERS (INDEX 28h T0 58h)
Table 19 Extended Audio ID Register
WOLFSON MICROELECTRONICS LTD
DATA BIT
CDAC
SDAC
AMAP
LDAC
VRM
VRA
DRA
ID1
ID0
FUNCTION
Variable rate audio support
Double rate audio support
Variable rate Mic ADC support
Centre DAC support
Surround DAC support
LFE DAC support
Slot to front DAC mapping support
Codec configuration – pin 45 value
Codec configuration – pin 46 value
These registers are specified as to use in Revision 2.1 of the AC’97 specification and have the
following functions on the WM9704Q:
REGISTER 28h – EXTENDED AUDIO ID
The Extended Audio ID register is a read only register that identifies which extended audio features
are supported (in addition to the original AC’97 features identified by reading the reset register at
index 00h). A non-zero value indicates the feature is supported. The indication of support for
6-channel surround sound changes depending on whether the WM9704Q is configured in mode 00
or otherwise.
REGISTER 2AH - EXTENDED AUDIO STATUS AND CONTROL REGISTER
The Extended Audio Status and Control Register is a read/write register that provides status and
control of the extended audio features.
Table 20 Extended Audio Status and Control Register
REGISTER 2Ch TO 32h – AUDIO SAMPLE RATE CONTROL REGISTERS
These registers are read/write registers that are written to, to select alternative sample rates for the
audio PCM converters. Default is the 48ks/s rate. Note that only Revision 2.1 recommended rates
are supported by the WM9704Q, selection of any other unsupported rates will cause the rate to
default to the nearest supported rate, and the supported rate value to be latched and so read back.
Register 2Ch is the front DAC rate register, but is also used for centre channel data rate.
I
2
S mode ONLY supports 48ks/s rates, NOT variable rates.
DATA BIT
MADC
CDAC
SDAC
LDAC
DRA
VRM
VRA
PRK
PRJ
PRL
PRI
FUNCTION
Enables variable rate audio mode
Enable double rate audio mode
Enables variable rate Mic ADC
Indicates centre DAC ready
Indicates surround DAC ready
Indicates LFE DAC ready
Indicates Mic ADC ready
Set to turn off centre DAC
Set to turn off surround DACs
Set to turn off LFE DACs
Set to turn off Mic ADC
Inverse of level at pin 45
Inverse of level at pin 46
ANY MODE BUT 10
0 (unless I
0 (unless I
0 (unless I
1
0
0
1
2
2
2
S = 1)
S = 1)
S = 1)
READ/WRITE
Read/write
Read/write
Read/write
Read/write
Read/write
Read/write
Read/write
Read
Read
Read
Read
1 when ID = 11 or I
1 when ID = 11 or I
Inverse of level at pin 45
Inverse of level at pin 46
WM9704Q SUPPORT
PD Rev 2.3 January 2001
MODE 10
Enable only
Enable only
Enable only
1
0
0
1
1
WM9704Q
Yes
Yes
Yes
Yes
No
No
No
No
2
2
S = 1
S = 1
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