AD1981BL Analog Devices, AD1981BL Datasheet - Page 12

• Manufacturer Part Number: AD1981BL
• Description: Low Voltage AC'97 Soundmax Codec
• Manufacturer: Analog Devices

AD1981BL
All registers not shown and bits containing an X are assumed to be reserved.
Refer to Table II for examples. 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 will read 1s whenever this bit is set to 1.
MV[4:0]
MVM
All registers not shown and bits containing an X are assumed to be reserved. Refer to Table III for examples.
PHV[4:0]
PHM
All registers not shown and bits containing an X are assumed to be reserved. Refer to Table III for examples.
All registers not shown and bits containing an X are assumed to be reserved. Refer to Table III for examples.
MCV[4:0]
M20
MCM
Reg
No. Name
06h
Reg
No. Name
0Ch Phone Volume
Reg
No. Name
0Eh MIC Volume
Mono Volume MVM
Mono Volume Control. The least significant bit represents 1.5 dB. This register controls the output from 0 dB to a
maximum attenuation of 46.5 dB.
Mono Volume Mute. When this bit is set to 1, the channel is muted.
Phone Volume. 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.
Phone Mute. When this bit is set to 1, the phone channel is muted.
MIC Volume Gain. 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.
MIC Gain Boost. This bit allows setting additional MIC gain to increase the microphone sensitivity. The nominal
gain boost by default is 20 dB; however, Bits D0 and D1 (MBG[1:0]) on the miscellaneous control bits register
(76h) allow changing the gain boost to 10 dB or 30 dB if necessary.
0 = Disabled; Gain = 0 dB
1 = Enabled; Default Gain = 20 dB (see Register 76h, Bits D0, D1)
MIC Mute. When this bit is set to 1, the MIC channel is muted.
D15
D15
PHM
D15
MCM X
D14 D13
X
D14 D13
X
D14 D13
D15
0
0
0
1
x in the above table is a wild card and has no effect on the value.
X
X
X
D12
X
D12
X
D12
X
Control Bits D[4:0] for Mono (06h)
WRITE
0000
0 1111
1 1111
x xxxx
D11
X
D11
X
D11
X
Phone Volume Register (Index 0Ch)
Table II. Volume Settings for Mono
Mono Volume Register (Index 06h)
MIC Volume Register (Index 0Eh)
D10
X
D10
X
D10
X
D9
X
D9
X
D9
X
READBACK
0 0000
0 1111
1 1111
x xxxx
–12–
D8
X
D8
X
D8
X
D7
X
D7
X
D7
X
D6
M20
X
X
D6
D6
D5
X
D5
X
D5
X
Function
0 dB Gain
–22.5 dB Gain
–46.5 dB Gain
– dB Gain, Muted
D4
MCV4
D4
MV4
D4
PHV4 PHV3 PHV2 PHV1 PHV0 8008h
D3
MCV3 MCV2
D3
MV3
D3
D2
D2
MV2
D2
D1
MCV1 MCV0 8008h
D1
MV1
D1
D0
D0
MV0
D0
Default
8000h
Default
Default
REV. 0