WM8711 Wolfson Microelectronics Ltd., WM8711 Datasheet - Page 27

• Manufacturer Part Number: WM8711
• Description: Internet Audio DAC With Integrated Headphone Driver
• Manufacturer: Wolfson Microelectronics Ltd.

WM8711
POWER DOWN MODES
WOLFSON MICROELECTRONICS LTD
The WM8711 contains power conservation modes in which various circuit blocks may be safely
powered down in order to conserve power. This is software programmable as shown in the table
below.
Table 19 Power Conservation Modes Software Control
Note:
1.
The power down control can be used to either a) permanently disable functions when not required in
certain applications or b) to dynamically power up and down functions depending on the operating
mode, e.g.: during playback or record. Please follow the special instructions below if dynamic
implementations are being used.
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 Headphone Output. 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.
Table 20 Standby Mode
0000110
Power Down
Control
0
0
0
When writing to register 0000110 bits 1 and 2 should be set to 1.
REGISTER
ADDRESS
0
1
1
0
0
1
0
3
4
5
6
7
1
1
1
BIT
1
1
1
LINEINPD
DACPD
OUTPD
OSCPD
CLKOUTPD
POWEROFF
LABEL
1
1
1
DESCRIPTION
STANDBY, but with Crystal Oscillator OS and
CLKOUT available
STANDBY, but with Crystal Oscillator OS
available, CLKOUT not-available
STANDBY, Crystal oscillator and CLKOUT not-
available.
1
1
1
0
0
1
DEFAULT
Line Input Power Down
1 = Enable Power Down
0 = Disable Power Down
DAC Power Down
1 = Enable Power Down
0 = Disable Power Down
Line Output Power Down
1 = Enable Power Down
0 = Disable Power Down
Oscillator Power Down
1 = Enable Power Down
0 = Disable Power Down
CLKOUT Power Down
1 = Enable Power Down
0 = Disable Power Down
Power Off Device
1 = Device Power Off
0 = Device Power On
PP Rev 1.2 November 2000
DESCRIPTION
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