ADSP-1981BL AD [Analog Devices], ADSP-1981BL Datasheet - Page 15

• Manufacturer Part Number: ADSP-1981BL
• Description: AC 97 SoundMAX Codec
• Manufacturer: AD [Analog Devices]

MONO VOLUME REGISTER
Index 0x06
This register controls the mono output volume and mute bit. The volume register contains five bits, generating 32 volume levels with
31 steps of 1.5 dB each. Because AC ’97 defines 6-bit volume registers, to maintain compatibility, whenever the D5 bit is set to 1, their
respective lower five volume bits are automatically set to 1 by the codec logic. On readback, all lower five bits read 1s whenever this bit is
set to 1. Refer to Table 14 for examples.
Reg No.
0x06
All registers are not shown, and bits containing an X are assumed to be reserved.
Table 13.
Bit
MV [4:0]
MVM
Table 14. Volume Settings for Mono
D15
0
0
0
1
An X is a wild card, and has no effect on the value.
PHONE VOLUME REGISTER
Index 0x0C
Reg No.
0x0C
All registers are not shown, and bits containing an X are assumed to be reserved. Refer to Table 17 for examples.
Table 15.
Bit
PHV [4:0]
PHM
All registers are not shown, and bits containing an X are assumed to be reserved. Refer to Table 17 for examples.
Name
Phone Volume
Name
Mono Volume
Write
0 0000
0 1111
1 1111
X XXXX
Mnemonic
Mono Volume Control
Mono Volume Mute
Mnemonic
Phone Volume
Phone Mute
D15
PHM
D15
MVM
D14
X
D14
X
Control Bits D [4:0] for Mono (0x06)
Function
The least significant bit represents 1.5 dB. This register controls the output from 0 dB to a maximum
attenuation of 46.5 dB.
When this bit is set to 1, the channel is muted.
D13
X
D13
X
Function
Allows setting the phone volume attenuator in 32 volume levels with 31 steps of 1.5 dB each. The
LSB represents 1.5 dB, and the gain range is +12 dB to −34.5 dB. The default value is 0 dB, with the
mute bit enabled.
When this bit is set to 1, the phone channel is muted.
D12
X
D12
X
D11
X
D11
X
Readback
0 0000
0 1111
1 1111
X XXXX
D10
X
Rev. A | Page 15 of 32
D10
X
D9
X
D9
X
D8
X
D8
X
D7
X
D7
X
D6
X
D6
X
D5
X
D5
X
D4
PHV4
Function
0 dB Gain
−22.5 dB Gain
−46.5 dB Gain
−∞ dB Gain, Muted
D4
MV4
D3
PHV3
D3
MV3
D2
PHV2
D2
MV2
PHV1
D1
D1
MV1
AD1981BL
D0
PHV0
D0
MV0
0x8000
Default
Default
0x8008