SigmaTel, Inc.
Data Sheet
STAC9721
. STAC9721/23 Powerdown/Powerup flow with analog still alive
Figure 12
PR0=1
PR1=1
PR4=1
ADCs off
PR0
Shut off
DACs off
PR1
Digital I/F
off PR4
Normal
Coda-link
PR1=0
PR0=0
&
Warm Reset
&
ADC=1
DAC=1
The above figure illustrates a state when all the mixers should work with the static volume settings that
are contained in their associated registers. This configuration can be used when playing a CD (or external
LINE_IN source) through STAC9721/23 to the speakers, while most of the system in low power mode.
The procedure for this follows the previous except that the analog mixer is never shut down.
30
04/07/00
04/07/00