WM9708

Advanced Information

WOLFSON MICROELECTRONICS LTD

AI Rev 2.0 April 2001

20

MUTE

MX4...MX0

FUNCTION

0

0 0000

0dB attenuation

0

0 0001

1.5dB attenuation

0

1 1111

46.5dB attenuation

1

x xxxx

Table 4 Volume Register Function

MASTER TONE CONTROL REGISTERS (INDEX 08h)

Optional register for support of tone controls (bass and treble). The WM9708 does not support bass

and treble and writing to this register will have no effect, reading will result in all zeros.

PC BEEP REGISTER (INDEX 0Ah)

This controls the level for the PC-beep input. Each step corresponds to approximately 3dB of

attenuation. The MSB of the register is the mute bit. When this bit is set to 1 the level for that channel

is set at -

WM9708 defaults to the PC-beep path being muted, except during reset when the path is open, so

an external speaker should be provided within the PC to alert the user to power on self-test

problems.

MUTE

PV3...PV0

FUNCTION

0

0000

0dB attenuation

0

1111

45dB attenuation

1

xxxx

Table 5 PC-beep Register Function

ANALOGUE MIXER INPUT GAIN REGISTERS (INDEX 0Ch - 18h AND 72h)

This controls the gain/attenuation for each of the analogue inputs and mixer PGA. Each step

corresponds to approximately 1.5dB. The MSB of the register is the mute bit. When this bit is set to 1

the level for that channel is set at -

REGISTER 0Eh (MIC VOLUME REGISTER)

This has an extra bit that is for a 20dB boost. When bit 6 is set to 1 the 20dB boost is on. The default

value is 8008h, which corresponds to 0dB gain with mute on.

The default value for the mono registers is 8008h, which corresponds to 0dB gain with mute on. The

default value for stereo registers is 8808h, which corresponds to 0dB gain with mute on.

MUTE

GX4...GX0

FUNCTION

0

00000

+12dB gain

0

01000

0dB gain

0

11111

-34.5dB gain

1

xxxxx

-

Table 6 Mixer Gain Control Register Function

RECORD SELECT CONTROL REGISTER (INDEX 1Ah)

Used to select the record source independently for right and left (see Table 7). The default value is

0000h, which corresponds to Mic in.