sta335bw STMicroelectronics, sta335bw Datasheet - Page 33

• Manufacturer Part Number: sta335bw
• Description: 2.1 Channels High Efficiency Digital Audio System
• Manufacturer: STMicroelectronics

STA335BW
5.7.5
Channel 3 / line output volume
The Volume structure of the STA335BW consists of individual volume registers for each
channel and a master volume register that provides an offset to each channels volume
setting. The individual channel volumes are adjustable in 0.5 dB steps from +48 dB to
-80 dB.
As an example if C3V = 0x00 or +48 dB and MV = 0x18 or –12 dB, then the total gain for
channel 3 = +36 dB.
The Master Mute when set to 1 mutes all channels at once, whereas the individual channel
mutes (CxM) mutes 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 commanding a value of all 1’s (255) to any channel
volume register or the master volume register. When volume offsets are provided via the
master volume register any channel that whose total volume is less than –80 dB is muted.
All changes in volume take place at zero-crossings when ZCE = 1 (configuration register F)
on a per channel basis as this creates the smoothest possible volume transitions. When
ZCE=0, volume updates occur immediately.
Table 15.
Table 16.
C3V7
D7
0
01001100 (0x4C)
11111110 (0xFE)
11111111 (0xFF)
01011111 (0x5F)
00000000 (0x00)
00000001 (0x01)
00000010 (0x02)
00000000 (0x00)
00000001 (0x01)
00000010 (0x02)
01100000 (0x60)
CxV(7..0)
MV(7..0)
Master volume offset as a function of MV(7..0)
Channel volume as a function of CxV(7..0)
…
…
…
C3V6
D6
1
C3V5
D5
1
C3V4
D4
0
Volume offset from channel value
C3V3
D3
0
Hard master mute
-127.5 dB
+47.5 dB
Volume
+0.5 dB
-0.5 dB
+48 dB
+47 dB
-38 dB
-1 dB
0 dB
0 dB
…
…
…
C3V2
D2
0
Register description
C3V1
D1
0
C3V0
D0
0
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