Cirrus Logic CS43L21 - Manual (Page 44)

44 DS723F1
CS43L21
This function will freeze the previous settings of, and allow modifications to be made to all control port reg-
isters without the changes taking effect until the FREEZE is disabled. To have multiple changes in the con-
trol port registers take effect simultaneously, enable the FREEZE bit, make all register changes, then
disable the FREEZE bit.
Notes:
1. This bit should only be used to synchronize run-time controls, such as volume and mute, during
normal operation. Using this bit before the relevant circuitry begins normal operation could cause the
change to take effect immediately, ignoring the FREEZE bit.
DAC De-Emphasis Control (DEEMPH)
Default: 0
0 - No De-Emphasis
1 - De-Emphasis Enabled
Function:
Note: The DATA_SEL[1:0] bits in reg09h must be set to ‘01’b to enable function control.
Enables the digital filter to apply the standard 15
s/50s digital de-emphasis filter response for a sample
rate of 44.1 kHz.
Analog Output Auto MUTE (AMUTE)
Default: 0
0 - Auto Mute Disabled
1 - Auto Mute Enabled
Function:
Enables (or disables) Automatic Mute of the analog outputs after 8192 “0” samples on each digital input
channel.
DAC Soft Ramp and Zero Cross Control (DAC_SZC[1:0])
Default = 10
00 - Immediate Change
01 - Zero Cross
10 - Soft Ramp
11 - Soft Ramp on Zero Crossings
Function:
Note: The DATA_SEL[1:0] bits in reg09h must be set to ‘01’b to enable function control
Immediate Change
When Immediate Change is selected all volume-level changes will take effect immediately in one step.
Zero Cross
This setting dictates that signal-level changes, either by gain changes, attenuation changes or muting, will
occur on a signal zero crossing to minimize audible artifacts. The requested level change will occur after a
timeout period between 1024 and 2048 sample periods (21.3 ms to 42.7 ms at 48 kHz sample rate) if the
signal does not encounter a zero crossing. The zero cross function is independently monitored and imple-
mented for each channel. Note: The LIM_SRDIS bit is ignored.