STA335BW
Register description
5.7.5
Channel 3 / line output volume
D7
D6
D5
D4
D3
D2
D1
D0
C3V7
0
C3V6
1
C3V5
1
C3V4
0
C3V3
0
C3V2
0
C3V1
0
C3V0
0
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. Master volume offset as a function of MV(7..0)
MV(7..0)
Volume offset from channel value
00000000 (0x00)
00000001 (0x01)
00000010 (0x02)
…
0 dB
-0.5 dB
-1 dB
…
01001100 (0x4C)
…
-38 dB
…
11111110 (0xFE)
11111111 (0xFF)
-127.5 dB
Hard master mute
Table 16. Channel volume as a function of CxV(7..0)
CxV(7..0)
Volume
00000000 (0x00)
00000001 (0x01)
00000010 (0x02)
…
+48 dB
+47.5 dB
+47 dB
…
01011111 (0x5F)
01100000 (0x60)
+0.5 dB
0 dB
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STMICROELECTRONICS [ ST ]
