AD1985 データシートの表示（PDF） - Analog Devices

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AD1985

AC ’97 SoundMAX® Codec

Analog Devices 

AD1985

AUX In Volume Register (Index 0x16)

Reg Num Name

D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 Default

0x16

AUX In Volume AM X X LAV4 LAV3 LAV2 LAV1 LAV0 AVRM1 X X RAV4 RAV3 RAV2 RAV1 RAV0 0x8808

1 For AC ’97 compatibility, Bit D7 (AVRM) is available only by setting the MSPLT bit in Register 0x76. The MSPLT bit enables separate mute bits for the left and right

channels. See the Volume Settings for Line In, CD Volume, AUX, and PCM Out table.

RAV[4:0]

AVRM

LAV[4:0]

AM

Right AUX Volume. Allows setting the AUX right channel gain/attenuator to one of 32 levels. The LSB represents 1.5

dB, and the gain range is +12 dB to –34.5 dB. The default value is 0 dB, mute enabled.

Right Channel Mute: Once enabled by the MSPLT bit in Register 0x76, this bit mutes the right channel separately

from the AM bit. Otherwise, this bit will always read 0 and will have no effect when set to 1.

Left AUX Volume. Allows setting the AUX left channel gain/attenuator to one of 32 levels. The LSB represents

1.5 dB, and the gain range is +12 dB to –34.5 dB. The default value is 0 dB, mute enabled.

AUX Volume Mute. When this bit is set to 1, both the left and right channels are muted, unless the MSPLT bit in

Register 0x76 is set to 1, in which case, this mute bit will only affect the left channel.

PCM Out Volume (Index 0x18)

Reg Num Name

D15 D14 D13 D12 D11 D10 D9 D8 D7

D6 D5 D4 D3 D2 D1 D0 Default

0x18

PCM Out Vol OM X X LOV4 LOV3 LOV2 LOV1 LOV0 OMRM1 X X ROV4 ROV3 ROV2 ROV1 ROV0 0x8808

1 For AC ’97 compatibility, Bit D7 (OMRM) is available only by setting the MSPLT bit in Register 0x76. The MSPLT bit enables separate mute bits for the left and right

channels. See the Volume Settings for Line In, CD Volume, AUX, and PCM Out table.

Note that depending on the state of the AC97NC bit in Register 0x76, this register has the following additional functionality:

• For AC97NC = 0, the register also controls the surround, center, and LFE DAC gain/attenuators.

• For AC97NC = 1, the register controls the PCM out volume only.

ROV[4:0]

OMRM

LOV[4:0]

OM

Right PCM Out Volume. Allows setting the PCM right channel gain/attenuator to one of 32 levels. The LSB represents 1.5 dB, and

the gain range is +12 dB to –34.5 dB. The default value is 0 dB, mute enabled.

Right Channel Mute. Once enabled by the MSPLT bit in Register 0x76, this bit mutes the right channel separately from the OM

bit. Otherwise, this bit will always read 0 and will have no effect when set to 1.

Left PCM Out Volume. Allows setting the PCM left channel gain/attenuator to one of 32 levels. The LSB represents 1.5 dB, and

the gain range is +12 dB to –34.5 dB. The default value is 0 dB, mute enabled.

PCM Out Volume Mute. When this bit is set to 1, both the left and right channels are muted, unless the MSPLT bit in Register

0x76 is set to 1, in which case, this mute bit will only affect the left channel.

Rev. A | Page 21 of 48

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