Datasheet

Registers STA309A
36/67 Doc ID 13855 Rev 4
7.2.23 Channel 4 volume trim, mute, bypass (0x16)
7.2.24 Channel 5 volume trim, mute, bypass (0x17)
7.2.25 Channel 6 volume trim, mute, bypass (0x18)
7.2.26 Channel 7 volume trim, mute, bypass (0x19)
7.2.27 Channel 8 volume trim, mute, bypass (0x1A)
The volume structure of the STA309A consists of individual volume registers for each
channel and a master volume register that provides an offset to each channels volume
setting. There is also an additional offset for each channel called the channel volume trim.
The individual channel volumes are adjustable in 0.5 dB steps from +48 dB to -78 dB. As an
example if C5V = 0xXX or +XXX dB and MV = 0xXX or -XX dB, then the total gain for
channel 5 = XX dB. The channel volume trim is adjustable independently on each channel
from -10 dB to +10 dB in 1 dB steps. The master mute when set to 1 will mute all channels
at once, whereas the individual channel mutes (CnM) 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 8192 samples from the maximum volume setting at the internal processing rate
(~192 kHz). A "hard mute" can be obtained by commanding a value of 0xFF (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 -91 dB will
be muted. All changes in volume take place at zero-crossings when ZCE = 1 (configuration
register H) on a per channel basis as this creates the smoothest possible volume transitions.
When ZCE = 0, volume updates occur immediately. Each channel also contains an
individual channel volume bypass. If a particular channel has volume bypassed via the
CnVBP = 1 register then only the channel volume setting for that particular channel affects
D7 D6 D5 D4 D3 D2 D1 D0
C4M C4VBP Reserved C4VT4 C4VT3 C4VT2 C4VT1 C4VT0
00010000
D7 D6 D5 D4 D3 D2 D1 D0
C5M C5VBP Reserved C5VT4 C5VT3 C5VT2 C5VT1 C5VT0
00010000
D7 D6 D5 D4 D3 D2 D1 D0
C6M C6VBP Reserved C6VT4 C6VT3 C6VT2 C6VT1 C6VT0
00010000
D7 D6 D5 D4 D3 D2 D1 D0
C7M C7VBP Reserved C7VT4 C7VT3 C7VT2 C7VT1 C7VT0
00010000
D7 D6 D5 D4 D3 D2 D1 D0
C8M C8VBP Reserved C8VT4 C8VT3 C8VT2 C8VT1 C8VT0
00010000