AD1980_15 Datasheet, PDF (21/32 Pages) Analog Devices – AC 97 SoundMAX Codec

AD1980
CENTER/LFE Volume Control Register (Index 36h)
Reg
No. Name
D15 D14 D13* D12 D11 D10 D9 D8 D7 D6 D5* D4 D3 D2 D1 D0 Default
36h Center/LFE LM X
Volume
LFE5 LFE4 LFE3 LFE2 LFE1 LFE0 CM X CNT5 CNT4 CNT3 CNT2 CNT1 CNT0 8080h
All registers not shown and bits containing an X are assumed to be reserved.
Refer to Table VII for examples. This register controls the LFE output volume and mute bit. The volume registers contain five bit, generating
32 volume levels with 31 steps of 1.5 dB each. If MSPLT is not set, Bit D7 has no effect.
*Because AC ’97 defines 6-bit volume registers, to maintain compatibility, whenever the D5 or D13 bit is set to “1,” its respective lower five volume bits are automati-
cally set to “1” by the codec logic. On readback, all lower five bits will read “1”s whenever this bit is set to “1.”
Note that depending on the state of the AC97NC bit in register 76h, this register operates as follows:
For AC97NC = 0, the register controls the center and LFE output pin Attenuators. Range is 0 dB to –46.5 dB.
For AC97NC = 1, the register controls the center and LFE DAC Gain/Attenuators. Range is +12 dB to –34.5 dB.
CNT[5:0]
CM
LFE[5:0]
LM
Center Volume Control
Center Volume Mute. When this bit is set to “1,” the channel is muted.
LFE Volume Control
LFE Volume Mute. When this bit is set to “1,” the channel is muted.
D15/D7
0
0
0
0
1
Table VII. Settings for Center/LFE Register
Control Bits
CENTER and LFE Volume (36h)
CENTER D[5:0] and LFE D[13:8]
WRITE
READBACK
Function with AC97NC = 0
00 0000
00 1111
01 1111
1x xxxx
xx xxxx
00 0000
00 1111
01 1111
01 1111
xx xxxx
0 dB Gain
–22 dB Gain
–46.5 dB Gain
–46.5 dB Gain
Muted
Function with AC97NC = 1
12 dB Gain
–10.5 dB Gain
–34.5 dB Gain
Not Applicable
Muted
Surround Volume Control Register (Index 38h)
Reg
No. Name
D15
D14 D13* D12 D11 D10 D9 D8 D7
D6 D5* D4 D3 D2 D1 D0 Default
38h Surround MUTE_L X LSR5 LSR4 LSR3 LSR2 LSR1 LSR0 MUTE_R X RSR5 RSR4 RSR3 RSR2 RSR1 RSR0 8080h
Volume
*Refer to Table VIII for examples. This register controls the surround volume controls for both stereo channels and mute bits. 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 Bit is set to 1, its respective lower five volume bits are automatically set to “1” by the coded logic. On readback , all lower five bits will read “1s” whenever
these bits are set to “1.”
Note that depending on the state of the AC97NC bit in Register 0x76, this register operates as follows:
For AC97NC = 0, the register controls the surround output pin Attenuators. Range is 0 dB to –46.5 dB.
For AC97NC = 1, the register controls the surround DAC Gain/Attenuators. Range is +12 dB to –34.5 dB.
RSR[5:0]
MUTE_R
LSR[5:0]
MUTE_L
Right Surround Volume Control
Right Surround Volume Mute. When this bit is set to “1,” the right channel is muted.
Left Surround Volume Control
Left Surround Volume Mute. When this bit is set to “1,” the left channel is muted.
REV. 0
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