AD1981BJST-REEL 데이터 시트보기 (PDF) - Analog Devices
부품명
상세내역
일치하는 목록
AD1981BJST-REEL Datasheet PDF : 28 Pages
| |||
AD1981B
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 Headphone HPM X X LHV LHV LHV LHV LHV RM* X X RHV RHV RHV RHV RHV 8000h
Volume
4
3
2
1
0
4
3
2
1
0
*For AC ’97 compatibility, Bit D7 (RM) 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, RM bit has no effect. All registers not shown and bits containing an X are assumed to be reserved.
Refer to Table I for examples. This register controls the headphone volume controls for both stereo channels and mute bit. Each
volume subregister 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 or D13 bits are set to 1, their respective lower five volume bits are automati-
cally set to 1 by the codec logic. On readback, all lower five bits will read 1s whenever these bits are set to 1.
RHV [4:0]
RM
LHV [4:0]
HPM
Right Headphone 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.
Right Channel Mute. Once enabled by the MSPLT bit in Register 76h, this bit mutes the right channel separately
from the HPM bit. Otherwise, this bit will always read 0 and will have no effect when set to 1.
Left Headphone 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.
Headphones Volume Mute. When this bit is set to 1, both the left and right channels are muted, unless the
MSPLT bit in Register 76h is set to 1, in which case this mute bit will affect only the left channel.
Table I. Volume Settings for Master and Headphone
Reg. 76h
Control Bits
Master Volume (02h) and Headphone Volume (04h)
MSPLT*
Left Channel Volume D[13:8]
Right Channel Volume D[5:0]
D15 WRITE READBACK Function
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, Right
Only 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 (RM) 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, RM bit has no effect.
X in the above table is a wild card and has no effect on the value.
REV. B
–11–
Share Link: 