AD1981B

Rev. C | Page 20 of 32

Table 26. Settings for Record Gain Register

Reg. 0x76

Control Bits Record Gain (1Channel)

Left-Channel Input Mixer D [11:8]

Right-Channel Input Mixer D [3:0]

MSPLT1

D15

Write

Readback

Function

D71

Write

Readback

Function

0

0

1111

1111

22.5 dB Gain

X

1111

1111

22.5 dB Gain

0

0

0000

0000

0 dB Gain

X

0000

0000

0 dB Gain

0

1

XXXX

XXXX

−∞ dB Gain,

Muted

X

XXXX

XXXX

−∞ dB Gain,

Muted

1

0

1111

1111

22.5 dB Gain

1

XXXX

XXXX

−∞ dB Gain,

Right Only

Muted

1

1

XXXX

XXXX

−∞ dB Gain,

Left Only

Muted

0

1111

1111

22.5 dB Gain

1

1

XXXX

XXXX

−∞ dB Gain,

Left Muted

1

XXXX

XXXX

−∞ dB Gain,

Right Muted

If MSPLT is not set, the RM bit has no effect.

X is a wild card and has no effect on the value.

GENERAL-PURPOSE REGISTER

Index 0x20

Reg No.

Name

D15

D14

D13

D12

D11

D10

D9

D8

D7

D6

D5

D4

D3

D2

D1

D0

Default

0x20

General-Purpose

X

X

X

X

X

X

MIX

MS

LPBK

X

X

X

X

X

X

X

0x0000

This register should be read before writing to generate a mask for only the bit(s) that need to be changed.

All registers are not shown, and bits containing an X are assumed to be reserved.

Table 27.

Bit

Mnemonic

Function

LPBK

Loopback Control

ADC/DAC Digital Loopback Mode.

0 = No Loopback (default).

1 = Loopback PCM Digital Data from ADC Output to DAC.

MS

MIC Select

Selects mono MIC input.

0 = Select MIC1.

1 = Select MIC2.

See the 2CMIC bit in Register 0x76 to enable stereo microphone recording.

MIX

Mono Output Select

Selects mono output audio source.

0 = Mixer Mono Output (reset default).

1 = MIC1 Channel.