WM8774 datasheet(22/42 Pages) WOLFSON

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WM8774

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PP Rev 1.0 June 2002

Each ADC channel also has an individual mute control bit, which mutes the input to the ADC. In

addition both channels may be muted by setting ADCMUTE.

BIT

LABEL

DEFAULT

DESCRIPTION

11001

ADC Mute

ADCMUTE

ADC MUTE Left and Right

0 : Normal Operation

1: mute ADC left and ADC right

11001

ADC Mute Left

MUTE

ADC Mute select

0 : Normal Operation

1: mute ADC left

11010

ADC Mute Right

MUTE

ADC Mute select

0 : Normal Operation

1: mute ADC right

The Record outputs may be enabled by setting RECEN, where RECEN enables the RECL and

RECR outputs.

BIT

LABEL

DEFAULT

DESCRIPTION

10100

REC Enable

RECEN

REC Output Enable

0 : REC output muted

1: REC output enabled

DE-EMPHASIS MODE

A digital De-emphasis filter may be applied to the DAC. The De-emphasis filter for each stereo

channel is enabled under the control of DEEMP.

BIT

LABEL

DEFAULT

DESCRIPTION

10101

DAC De-emphasis

Control

DEEMPH

De-emphasis mode select:

0 : Normal Mode

1: De-emphasis Mode

Refer to Figure 26, Figure 27, Figure 28, Figure 29, Figure 30 and Figure 31 for details of the De-

Emphasis modes at different sample rates.

POWERDOWN MODE AND ADC/DAC DISABLE

Setting the PDWN register bit immediately powers down the WM8774, including the references,

overriding all other powerdown 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. It is recommended that the 8-channel input mux and buffer, ADC, DAC and output

mixers and EVRs are powered down before setting PDWN.

BIT

LABEL

DEFAULT

DESCRIPTION

11000

Powerdown Control

PDWN

Power Down Mode Select:

0 : Normal Mode

1: Power Down Mode

The ADC and DACs may also be powered down by setting the ADCD and DACD disable bits. Setting

ADCD will disable the ADC and select a low power mode. The ADC digital filters will be reset and will

reinitialise when ADCD is reset. Setting DACD disable the DAC and select a low power mode.

Resetting DACD will reinitialise the digital filters.

BIT

LABEL

DEFAULT

DESCRIPTION

ADCD

ADC Disable:

0 : Normal Mode

1: Power Down Mode

11000

Powerdown Control

DACD

1111

DAC Disable:

0 : Normal Mode

1: Power Down Mode

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