Production Data
WM8711BL
DACPD: Powers down the DAC and DAC Digital Filters. If this is done dynamically then audible pops
will result unless the following guidelines are followed. In order to prevent pops, the DAC should first
be soft-muted (DACMU), the output should then be de-selected from the line and headphone output
(DACSEL), then the DAC powered down (DACPD). This is of use when the device enters Pause or
Stop modes. During DACPD the digital audio interface is remains active.
OUTPD: Powers down the Line and Headphone Outputs. If this is done dynamically then audible
pops may result unless the DAC is first soft-muted (DACMU). This is of use when the device enters
Record, Pause or Stop modes.
The device can be put into a standby mode (STANDBY) by powering down all the audio circuitry
under software control as shown in Table 20.
DESCRIPTION
STANDBY, but with Crystal Oscillator OS and CLKOUT
available
0
0
0
0
1
1
0
0
1
1
1
1
1
1
1
STANDBY, but with Crystal Oscillator OS available,
CLKOUT not-available
STANDBY, Crystal oscillator and CLKOUT not-available.
Table 20 Standby Mode
In STANDBY mode the Control Interface, a small portion of the digital and areas of the analogue
circuitry remain active. The active analogue includes the analogue VMID reference so that the
analogue line outputs and headphone outputs remain biased to VMID. This reduces any audible
effects caused by DC glitches when entering or leaving STANDBY mode.
The device can be powered off by writing to the POWEROFF bit of the Power Down register. In
POWEROFF mode the Control Interface and a small portion of the digital remain active. The
analogue VMID reference is disabled. Refer to Table 21.
DESCRIPTION
POWEROFF, but with Crystal Oscillator OS and
CLKOUT available
1
1
1
0
1
1
0
0
1
X
X
X
1
1
1
POWEROFF, but with Crystal Oscillator OS
available, CLKOUT not-available
POWEROFF, Crystal oscillator and CLKOUT
not-available.
Table 21 Poweroff Mode
PD, Rev 4.1, April 2007
33
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WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
