
REV. 0
–12–
AD1888
Phone_in Volume Register (Index 0Ch)
Reg
No. Name
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
Default
0Ch Phone_in Volume PHM X
X
X
X
X
X
X
X
X
X
PHV4
PHV3
PHV2
PHV1
PHV0
8008h
All registers not shown and bits containing an X are assumed to be reserved. Refer to Table III for examples.
PHV[4:0]
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.
PHM
Phone Mute. When this bit is set to 1, the Phone channel is muted.
MIC Volume Register (Index 0Eh)
Reg
No. Name
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
Default
0Eh MIC Volume
MCM
X
X
X
X
X
X
X
X
M20
X
MCV4
MCV3
MCV2
MCV1
MCV0
8008h
All registers not shown and bits containing an X are assumed to be reserved. Refer to Table III for examples.
MCV[4:0]
MIC Volume Gain. Allows setting the MIC Volume attenuator in 32 volume levels. The LSB represents 1.5 dB,
and the gain range is +12 dB to –34.5 dB. The default value is 0 dB, with mute enabled.
M20
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)
MCM
MIC Mute. When this bit is set to 1, the channel is muted.
Table III. Volume Settings for Phone and MIC
Control Bits D[4:0]
Phone (0Ch) and MIC (0Eh)
WRITE
D15
READBACK
Function
0
0
0
1
0 0000
0 1000
1 1111
x xxxx
0 0000
0 1000
1 1111
x xxxx
12 dB Gain
0 dB Gain
–34.5 dB Gain
– dB Gain, Muted
x in the above table is a wild card, and has no effect on the value.