Production Data

WM8768

w

PD Rev 4.1 March 2005

29

POWERDOWN MODE AND DAC DISABLE

Setting the PDWN register bit immediately powers down the DACs on the WM8768, overriding the

DACD powerdown bits control bits. All trace of the previous input samples is removed, but all control

register settings are preserved. When PDWN is cleared the digital filters will be reinitialised

REGISTER ADDRESS

BIT

LABEL

DEFAULT

DESCRIPTION

0000010

Powerdown Control

2

PDWN

0

Power Down all DAC’s Select:

0: All DACs enabled

1: All DACs disabled

The DACs may also be powered down individually by setting the DACPD disable bits. Each Stereo

DAC channel has a separate disable DACPD[2:0]. Setting DACPD for a channel will disable the

DACs and select a low power mode.

REGISTER ADDRESS

BIT

LABEL

DEFAULT

DESCRIPTION

0001010

Powerdown Control

3:1

DACD[2:0]

000

DAC Disable

0001111

DAC4 Control

1

DACD4

0

DAC 4 Powerdown

{DACD4,DACD [2:0]}

DAC

CHANNEL 4

DAC

CHANNEL 3

DAC

CHANNEL 2

DAC

CHANNEL 1

0000

Active

Active

Active

Active

0001

Active

Active

Active

DISABLE

0010

Active

Active

DISABLE

Active

0011

Active

Active

DISABLE

DISABLE

0100

Active

DISABLE

Active

Active

0101

Active

DISABLE

Active

DISABLE

0110

Active

DISABLE

DISABLE

Active

0111

Active

DISABLE

DISABLE

DISABLE

1000

DISABLE

Active

Active

Active

1001

DISABLE

Active

Active

DISABLE

1010

DISABLE

Active

DISABLE

Active

1011

DISABLE

Active

DISABLE

DISABLE

1100

DISABLE

DISABLE

Active

Active

1101

DISABLE

DISABLE

Active

DISABLE

1110

DISABLE

DISABLE

DISABLE

Active

1111

DISABLE

DISABLE

DISABLE

DISABLE

Table 15 DAC Disable Control

MASTER POWERDOWN

Control bit PWRDNALL overrides the {DACD4,DACD[2:0]} bits and powers everything down

including the reference VMID. It is recommended that the DACs are powered down first before

setting this bit.

REGISTER ADDRESS

BIT

LABEL

DEFAULT

DESCRIPTION

0001010

Interface Control

4

PWRDNALL

0

Master Power down bit

0: Not powered down

1: Powered down