WM9703

Production Data

WOLFSON MICROELECTRONICS LTD

PD Rev 3.4 January 2001

26

DATA BIT

FUNCTION

ANY MODE

VRA

Variable rate audio support

1

DRA

Double rate audio support

0

VRM

Variable rate Mic ADC support

0

CDAC

Centre DAC support

0

SDAC

Surround DAC support

0

LDAC

LFE DAC support

0

AMAP

Slot to front DAC mapping support

1

ID1

Codec configuration – pin 45 value

Inverse of level at pin 45

ID0

Codec configuration – pin 46 value

Inverse of level at pin 46

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.

DATA BIT

FUNCTION

READ/WRITE

WM9703 SUPPORT

VRA

Enables variable rate audio mode

Read/write

Yes

DRA

Enable double rate audio mode

Read/write

No

VRM

Enables variable rate Mic ADC

Read/write

No

CDAC

Indicates centre DAC ready

Read

Yes

SDAC

Indicates surround DAC ready

Read

Yes

LDAC

Indicates LFE DAC ready

Read

Yes

MADC

Indicates Mic ADC ready

Read

No

PRI

Set to turn off centre DAC

Read/write

Enable only

PRJ

Set to turn off surround DACs

Read/write

Enable only

PRK

Set to turn off LFE DACs

Read/write

Enable only

PRL

Set to turn off Mic ADC

Read/write

No

Table 19 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 WM9703, 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.

REGISTERS 36h AND 38h – 6 CHANNEL VOLUME CONTROL

These read/write registers control the output volume of the optional four PCM channels. (not

supported by the WM9703)

VENDOR RESERVED REGISTERS (INDEX 5Ah AND 7Ah)

These registers are vendor specific. Do not write to these registers unless the Vendor ID register has

been checked first to ensure that the driver knows the source of the AC ‘97 component.

VENDOR SPECIFIC GAIN CONTROL REGISTERS – (INDEX 70h TO 74h)

Not used in the WM9703.

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 REVISION7 to REVISION0 field

is for the Vendor Revision number. In the WM9703 the vendor ID is set to WML3.

Wolfson is a registered Microsoft Plug and Play vendor.