TC9455,88F/N

2002-02-05

6

4.

Electronic volume controllers

The IC incorporates microphone input 1 (MIC1) and microphone input 2 (MIC2) volume and echo volume

controllers. The built-in volume controller operates in 16 steps. Using an external variable resistor, volume

can be controlled by the DC level or from the MCU using serial data.

4.1

Serial control timing

Figure 4 shows the serial control timing.

Figure 4

Serial control timing

Table 1 lists bits used to set the volume.

Table 1

Volume setting bits

M3, M2, M1, M0: Volume setting data

MODE

DA7

DA6

DA5

DA4

DA3

DA2

DA1

DA0

VOL1 setting

M3

M2

M1

M0

0

0

0

0

VOL2 setting

M3

M2

M1

M0

0

1

0

0

VOL3 setting

M3

M2



M1

M0

1



0

0

0

VOL1, 2, 3 setting

M3

M2

M1

M0

1

1

0

0