Preliminary Technical Data
WM8766
DE-EMPHASIS MODE
Each stereo DAC channel has an individual de-emphasis control bit:
REGISTER ADDRESS
BIT
LABEL
DEEMPH
[1:0]
DEFAULT
DESCRIPTION
0001001
[8:6]
000
De-emphasis Channel Selection
Select:
DAC De-Emphahsis
Control
DEEMPH
[1:0]
000
DAC CHANNEL 1
DAC CHANNEL 2
DAC CHANNEL 3
Not DE-EMPHASIS
DE-EMPHASIS
Not DE-EMPHASIS
Not DE-EMPHASIS
DE-EMPHASIS
Not DE-EMPHASIS
Not DE-EMPHASIS
Not DE-EMPHASIS
Not DE-EMPHASIS
DE-EMPHASIS
001
010
Not DE-EMPHASIS
DE-EMPHASIS
011
DE-EMPHASIS
100
Not DE-EMPHASIS
DE-EMPHASIS
Not DE-EMPHASIS
Not DE-EMPHASIS
DE-EMPHASIS
101
DE-EMPHASIS
110
Not DE-EMPHASIS
DE-EMPHASIS
DE-EMPHASIS
111
DE-EMPHASIS
DE-EMPHASIS
Refer to Figure 27 for details of the De-Emphasis performance at different sample rates.
REGISTER ADDRESS
0000010
BIT
LABEL
DEFAULT
DESCRIPTION
DEMMP Select:
1
DEEMPALL
0
DAC DEMP
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
0000010
BIT
LABEL
DEFAULT
DESCRIPTION
Power Down all DAC’s Select:
0: All DAC’s enabled
2
PDWN
0
Powerdown Control
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
0001010
BIT
LABEL
DEFAULT
DESCRIPTION
DAC Disable
3:1 DACPD[2:0]
000
Powerdown Control
DACPD [2:0]
000
DAC CHANNEL 1
Active
DAC CHANNEL 2
DAC CHANNEL 3
Active
Active
Active
Active
001
DISABLE
Active
010
DISABLE
DISABLE
Active
Active
011
DISABLE
Active
Active
100
DISABLE
DISABLE
DISABLE
DISABLE
101
DISABLE
Active
Active
110
DISABLE
DISABLE
111
DISABLE
PTD Rev 2.3 February 2004
23
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WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
