TLC320AD91 Datasheet, PDF (29/43 Pages) Texas Instruments – Stereo Audio Codec

Figure 2–8 illustrates one example procedure for a complete power down of the TLC320AD91C. From
normal operation, sequential writes to the General-Purpose register are performed to power down the
TLC320AD91C one section at a time. After all of the other sections have been shut down, a final write (of
PR4) can be executed to shut down the TLC320AD91C digital interface (AC-link). The device remains in
sleep mode with all registers holding their static values. To wake up the TLC320AD91C, the digital controller
sends a pulse on SYNC which issues a warm reset. This operation restarts the TLC320AD91C digital
interface (resets PR4 to zero). The TLC320AD91C can also be awakened with a cold reset. A cold reset
causes a loss of the register values since a cold reset sets the registers back to their default states. When
a section is powered back on, the Power Down register (index 26h) should be read to verify that the section
is ready (i.e., stable) before any operation that requires the section is attempted.
PR0 = 1
PR1 = 1
PR2 = 1
PR4 = 1
Normal
ADCs Off
PR0
DACs Off
PR1
Analog Off
PR2 or
PR3
Digital I/F
Off
PR4
Shut Off
AC-Link
PR0 = 0
and
ADC = 1
PR1 = 0
and
DAC = 1
Ready = 1
PR2 = 0
and
ANL = 1
Warm Reset
Default
Cold Reset
Figure 2–8. TLC320AD91C Power-Down/ Power-Up Flow Example
Figure 2–9 illustrates an example procedure where all of the mixers are operational with the static volume
settings contained in their associated registers. This procedure is used when a CD is played (or external
LINE source) through the TLC320AD91C to the speakers but most of the system is in low-power mode. This
procedure follows the previous procedure, except that the analog mixer is never shut down.
PR0 = 1
PR1 = 1
PR4 = 1
Normal
ADCs Off
PR0
DACs Off
PR1
Digital I/F
Off
PR4
Shut Off
AC-Link
PR0 = 0
and
ADC = 1
PR1 = 0
and
DAC = 1
Warm Reset
Figure 2–9. TLC320AD91C Power-Down/Power-Up Flow Example With Analog Still Alive
2–17