WM9707
Advanced Information
VENDOR SPECIFIC GAIN CONTROL REGISTERS – (INDEX 72h)
This register controls the gain and mute functions applied to the mixer path. This PGA is not
accommodated in the Intel specification, but is required in order to allow the option of simultaneous
recording of the mixer output and playback of DAC signals. The function is as per the other mixer
PGA’s. However, the default value of the register is not-muted. If it is not used it will be transparent to
the user.
VENDOR ID REGISTERS (INDEX 7Ch TO 7Eh)
This register is for specific vendor identification if so desired. The ID method is Microsoft’s Plug and
Play Vendor ID code. The first character of that ID is F7 to F0, the second character S7 to S0, and
the third T7 to T0. These three characters are ASCII encoded. The REV7 to REV0 field is for the
Vendor Revision number. In the WM9707 the vendor ID is set to WML3.
Wolfson is a registered Microsoft Plug and Play vendor.
VENDOR ID REGISTERS (INDEX 74h)
This register describes how data is mapped to the AC’97 DACs. Register 74h can be used to change
the incoming DAC data slots that are used by the on-board DACs. This allows software control of
multiple codecs.
SURROUND SOUND
DSS1, DSS0
PCM OUT LEFT
PCM OUT RIGHT
00
01
1X
3
7
6
4
8
9
Table 15 Vendor ID Registers - Reg 74 [1:0]
SURROUND SOUND
ASS1, ASS0
PCM IN LEFT
PCM IN RIGHT
00
01
1X
3
7
6
4
8
9
Table 16 Vendor ID Registers – Reg 74 [9:8]
This register describes how data is mapped onto the AC-link. Register 74h can be used to map ADC
data onto multiple AC-link slots under software control.
This allows the user to connect multiple codecs to a host controller using a single AC-link interface.
The volume control register is still 02h and the rate register is 2Ch. The ID pins have no effect on this
mapping.
WOLFSON MICROELECTRONICS LTD
AI Rev 2.2 January 2001
26
WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
