wm9704m Wolfson Microelectronics plc, wm9704m Datasheet - Page 29

• Manufacturer Part Number: wm9704m
• Description: Amc97 Audio Modem Codec
• Manufacturer: Wolfson Microelectronics plc

Production Data
REV 2.1 REGISTERS (INDEX 28H T0 58H)
WOLFSON MICROELECTRONICS LTD
POWERDOWN CONTROL/STATUS REGISTER (INDEX 26H)
Note that in order to go into ultimate low power mode, PR5 is required to be set which turns
off the oscillator circuit. Asserting SYNC resets the PR5 bit and re-starts the oscillator in the
same was as the AC link is restarted.
Also when RESETB pin is asserted low, all PR bits are over-ridden and the entire device is
powered off to ultra low power state for as long as RESETB = low. On releasing RESETB,
the device is reset (all active) and powered up.
These registers are specified as to use in Rev 2.1 of the AC’97 specification and have the following
functions on the WM9704M:
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.
Table 18 Extended Audio Capability Register
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 19 Extended Audio Status and Control Register
DATA BIT
MADC
CDAC
SDAC
LDAC
DRA
VRM
VRA
PRK
PRJ
PRL
DATA BIT
PRI
CDAC
AMAP
SDAC
LDAC
VRM
VRA
DRA
ID1
ID0
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
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
READ/WRITE
Read/write
Read/write
Read/write
Read/write
Read/write
Read/write
Read/write
Read
Read
Read
Read
Inverse of level at pin 45
Inverse of level at pin 46
0 (unless I
0 (unless I
WM9704M SUPPORT
PD Rev 3.2 January 2001
VALUE
Enable only
Enable only
Enable only
1
0
0
0
1
2
2
WM9704M
Yes
Yes
Yes
Yes
S = 1)
S = 1)
No
No
No
No
29