AD1888 Datasheet, PDF (11/32 Pages) Analog Devices – AC 97 SoundMAX Codec

AD1888
Headphones Volume Register (Index 04h)
Reg
No. Name
D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 Default
04h Headphones HPM X
Volume
LHV5 LHV4 LHV3 LHV2 LHV1 LHV0 HPRM* X RHV5 RHV4 RHV3 RHV2 RHV1 RHV0 8000h
*For AC ’97 compatibility, Bit D7 is available only by setting the MSPLT bit, Register 76h. The MSPLT bit enables separate mute bits for the left and right
channels. If MSPLT is not set, Bit D7 has no effect.
Table I. Volume Settings for Master and Headphone
Reg. 76h
Control Bits
Master Volume (02h) and Headphone Volume (04h)
Left Channel Volume D[13:8]
MSPLT* D15 WRITE READBACK Function
Right Channel Volume D[5:0]
D7* WRITE READBACK Function
0
0 00 0000 00 0000
0 dB Gain
x 00 0000 00 0000
0 dB Gain
0
0 00 1111 00 1111
–22.5 dB Gain
x 00 1111 00 1111
–22.5 dB Gain
0
0 01 1111 01 1111
–46.5 dB Gain
x 01 1111 01 1111
–46.5 dB Gain
0
0 1x xxxx 01 1111
–46.5 dB Gain
x 1x xxxx 01 1111
–46.5 dB Gain
0
1 xx xxxx xx xxxx
–ϱ dB Gain, Muted
x xx xxxx xx xxxx
–ϱ dB Gain, Muted
1
0 1x xxxx 01 1111
–46.5 dB Gain
1 xx xxxx xx xxxx
–ϱ dB Gain, only
Right Muted
1
1 xx xxxx xx xxxx
–ϱ dB Gain, Left only Muted 0 xx xxxx xx xxxx
–46.5 dB Gain
1
1 xx xxxx xx xxxx
–ϱ dB Gain, Left Muted
1 xx xxxx xx xxxx
–ϱ dB Gain, Right
Muted
*For AC ’97 compatibility, Bit D7 is available only by setting the MSPLT bit, Register 76h. The MSPLT bit enables separate mute bits for the left and right
channels. If MSPLT is not set, Bit D7 has no effect.
x in the above table is “don’t care.”
Mono Volume Register (Index 06h)
Reg
No. Name
D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5* D4 D3 D2 D1 D0 Default
06h Mono Volume MVM X X X X X X X X X MV5 MV4 MV3 MV2 MV1 MV0 8000h
*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. All registers not shown and bits containing
an X are assumed to be reserved.
MV[5:0]
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.
REV. 0
Table II. Volume Settings for Mono
Control Bits D[4:0] for Mono (06h)
D15
WRITE
READBACK
0
0 0000
0
0 1111
0
1 1111
1
x xxxx
0 0000
0 1111
1 1111
x xxxx
x in the above table is a wild card and has no effect on the value.
Function
0 dB Gain
–22.5 dB Gain
–46.5 dB Gain
–ϱ dB Gain, Muted
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