Preliminary Technical Data

WM8766

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PTD Rev 2.3 February 2004

23

DE-EMPHASIS MODE

Each stereo DAC channel has an individual de-emphasis control bit:

REGISTER ADDRESS

BIT

LABEL

DEFAULT

DESCRIPTION

0001001

DAC De-Emphahsis

Control

[8:6]

DEEMPH

[1:0]

000

De-emphasis Channel Selection

Select:

DEEMPH

[1:0]

DAC CHANNEL 1

DAC CHANNEL 2

DAC CHANNEL 3

000

Not DE-EMPHASIS

Not DE-EMPHASIS

Not DE-EMPHASIS

001

DE-EMPHASIS

Not DE-EMPHASIS

Not DE-EMPHASIS

010

Not DE-EMPHASIS

DE-EMPHASIS

Not DE-EMPHASIS

011

DE-EMPHASIS

DE-EMPHASIS

Not DE-EMPHASIS

100

Not DE-EMPHASIS

Not DE-EMPHASIS

DE-EMPHASIS

101

DE-EMPHASIS

Not DE-EMPHASIS

DE-EMPHASIS

110

Not DE-EMPHASIS

DE-EMPHASIS

DE-EMPHASIS

111

DE-EMPHASIS

DE-EMPHASIS

DE-EMPHASIS

Refer to Figure 27 for details of the De-Emphasis performance at different sample rates.

REGISTER ADDRESS

BIT

LABEL

DEFAULT

DESCRIPTION

0000010

DAC DEMP

1

DEEMPALL

0

DEMMP Select:

0 : Normal operation

1: De-emphasis all channels

POWERDOWN MODE AND DAC DISABLE

Setting the PDWN register bit immediately powers down the DAC’s on the WM8766, overriding the

DACD powerdown bits control bits. All trace of the previous input samples are 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 DAC’s enabled

1: All DAC’s disabled

The DACs may also be powered down individually by setting the DACPD disable bit. 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

DACPD[2:0]

000

DAC Disable

DACPD [2:0]

DAC CHANNEL 1

DAC CHANNEL 2

DAC CHANNEL 3

000

Active

Active

Active

001

DISABLE

Active

Active

010

Active

DISABLE

Active

011

DISABLE

DISABLE

Active

100

Active

Active

DISABLE

101

DISABLE

Active

DISABLE

110

Active

DISABLE

DISABLE

111

DISABLE

DISABLE

DISABLE