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STA320

5.7.5 Master Volume Register

5.7.6 Channel 1 Volume

5.7.7 Channel 2 Volume

5.7.8 Channel 3 Volume

The Volume structure of the STA320 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 0.5dB steps from +48dB to -80 dB.

As an example if C3V = 00h or +48dB and MV = 18h or -12dB, then the total gain for channel 3 = +36dB.

The Master Mute when set to 1 will mute all channels at once, 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(~96kHz). A "hard mute"

can be obtained by commanding a value of all 1's(255) to any channel volume register or the master vol-

ume register. When volume offsets are provided via the master volume register any channel that whose

total volume is less than -80dB will be muted.

All changes in volume take place at zero-crossings when ZCE = 1(configuration register F) on a per chan-

nel basis as this creates the smoothest possible volume transitions. When ZCE=0, volume updates will

occur immediately.

Table 16. Master Volume Offset as a function of MV(7..0).

D7

D6

D5

D4

D3

D2

D1

D0

MV7MV6

MV5

MV4

MV3MV2

MV1MV0

111111

11

D7

D6

D5

D4

D3

D2

D1

D0

C1V7

C1V6

C1V5

C1V4

C1V3

C1V2

C1V1

C1V0

011000

00

D7

D6

D5

D4

D3

D2

D1

D0

C2V7

C2V6

C2V5

C2V4

C2V3

C2V2

C2V1

C2V0

011000

00

D7

D6

D5

D4

D3

D2

D1

D0

C3V7

C3V6

C3V5

C3V4

C3V3

C3V2

C3V1

C3V0

011000

00

MV(7..0)

Volume Offset from Channel Value

00000000(00h)

0dB

00000001(01h)

-0.5dB

00000010(02h)

-1dB

……

01001100(4Ch)

-38dB

……

11111110(FEh)

-127dB

11111111(FFh)

Hard Master Mute