WM8776
Production Data
ADC MUTE
Each ADC channel also has an individual mute control bit, which mutes the input to the ADC PGA.
By setting the LRBOTH bit (reg22, bit 8) both channels can be muted simultaneously.
REGISTER ADDRESS
R21 (15h)
BIT
LABEL
DEFAULT
DESCRIPTION
ADC Mute select
7
MUTELA
0
0010101
0 : Normal Operation
1: mute ADC left
ADC Mute Left
R21 (15h)
6
MUTERA
0
ADC Mute select
0001111
0 : Normal Operation
1: mute ADC right
ADC Mute Right
DE-EMPHASIS MODE
The De-emphasis filter for the DAC is enabled under the control of DEEMP.
REGISTER ADDRESS
R9 (09h)
BIT
LABEL
DEFAULT
DESCRIPTION
De-emphasis mode select:
0 : Normal Mode
0
DEEMPH
0
0001001
DAC De-emphasis
Control
1: De-emphasis Mode
Refer to Figure 35, Figure 36, Figure 37, Figure 38, Figure 39 and Figure 40 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 WM8776, including the references,
overriding all other powerdown 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 re-initialised.
It is recommended that the 5-channel input mux and buffer, ADC and DAC are powered down before
setting PDWN.
REGISTER ADDRESS
R13 (0Dh)
BIT
LABEL
DEFAULT
DESCRIPTION
Power Down Mode Select:
0 : Normal Mode
0
PDWN
0
0001101
Powerdown Control
1: Power Down Mode
The ADC, DAC and HEADPHONE PGA’S 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. The DAC has a separate disable
DACD. Setting DACD will disable the DAC, mixer and output PGAs. Resetting DACD will reinitialise
the digital filters.
REGISTER ADDRESS
R13 (0Dh)
BIT
LABEL
DEFAULT
DESCRIPTION
ADC Powerdown:
1
ADCPD
0
0001101
0 : Normal Mode
1: Power Down Mode
DAC Powerdown:
Powerdown Control
2
3
DACPD
HPPD
0
1
0 : Normal Mode
1: Power Down Mode
Headphone output/PGA Power
down :
0 : HP out enabled
1 : HP out disabled
The analogue audio inputs and outputs can also be individually powered down by setting the relevant
bits in the powerdown register.
PD Rev 4.0 April 2005
28
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WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
