sta323wqs STMicroelectronics, sta323wqs Datasheet - Page 47

• Manufacturer Part Number: sta323wqs
• Description: 2.1-channel High-efficiency Digital Audio System With Qsound Qhd??
• Manufacturer: STMicroelectronics

STA323WQS
7.8.3
Channel 2 volume (address 0x09)
Channel 3 volume (address 0x0A)
Volume description
The volume structure of the STA323WQS consists of individual volume registers for each of
the three channels and a master volume register, and individual channel volume trim
registers. The channel volume settings are normally used to set the maximum allowable
digital gain and to hard-set gain differences between certain channels. These values are
normally set at the initialization of the IC and not changed. The individual channel volumes
are adjustable in 0.5 dB steps from +48 dB to -80 dB. The master volume control is normally
mapped to the master volume of the system. The values of these two settings are summed
to find the actual gain or volume value for any given channel.
When set to 1, the Master Mute will mute all channels, whereas the individual channel
mutes (CxM) will mute only that channel. Both the Master Mute and the Channel Mutes
provide a “soft mute” with the volume ramping down to mute in 4096 samples from the
maximum volume setting at the internal processing rate (~96 kHz). A “hard mute” can be
obtained by setting a value of all 1’s (FFh) in any channel volume register or the master
volume register. When volume offsets are provided, via the master volume register, any
channel whose total volume is less than –100dB is muted.
All changes in volume take place at zero-crossings when ZCE = 1 (configuration register E)
on a per channel basis as this creates the smoothest possible volume transitions. When
ZCE=0, volume updates occur immediately.
The STA323WQS also features a soft-volume update function. When SVE = 1 (in
configuration register E) the volume ramps between intermediate values when the value is
updated, This feature can be disabled by setting SVE = 0.
Each channel also contains an individual channel volume bypass. If a particular channel has
volume bypassed via the CxVBP = 1 register then only the channel volume setting for that
particular channel affects the volume setting, the master volume setting does not affect that
channel. Also, master soft-mute does not affect the channel if CxVBP = 1.
Each channel also contains a channel mute. If CxM = 1 a soft mute is performed on that
channel.
C2V7
C3V7
D7
D7
0
0
C2V6
C3V6
D6
D6
1
1
C2V5
C3V5
D5
D5
1
1
C2V4
C3V4
D4
D4
0
0
C2V3
C3V3
D3
D3
0
0
C2V2
C3V2
D2
D2
0
0
Register descriptions
C2V1
C3V1
D1
D1
0
0
C2V0
C3V0
D0
D0
0
0
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