Audio Codec (AC)
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351
[6]
ALC_NOISE_GAIN_HD
R/W
1'b0
ALC hold gain when noise gate mode
1'b0: Don’t hold gain in noise gate mode (depending on
noise gate threshold to do noise gate's AGC)
1'b1: Hold gain in noise gate mode
[10:7]
ALC_NOISE_GATE_EXP
R/W
4'h4
ALC noise_gate boost control
4'b0000: 0dB
4'b0001: 3dB
4'b0010: 6dB
...
4'b1111: 45dB (3dB/step)
[11]
ALC_NOISE_GATE_EN
R/W
1'b0
ALC noise_gate mode control
1'b0: Disable noise_gate mode
1'b1: Enable noise_gate mode
[12]
ALC_NOISE_GATE_DROP_EN
R/W
1'b0
ALC noise_gate drop mode control
1'b0: Disable noise_gate_drop mode
1'b1: Enable noise_gate_drop mode
[14:13]
ALC_NOISE_GATE_RATIO_SEL R/W
2'b01
ALC DRC expansion ratio select control, when noise gate is
enabled
2'b00: 1:1
2'b01: 2:1
2'b10: 4:1
2'b11: 8:1
[15]
RSVD
N/A
1’b0
Reserved
17.6.2.19
0x20
Address
Bit
Name
Access
Reset Description
0x20
[1:0]
ALC_NOISE_RANGE
R/W
2'h1
Noise gate threshold margin control in ALC
2'b00: +-0dB
2'b01: +-1.5dB
2'b10: +-3.0dB
2'b11: +-4.5dB
[9:2]
ALC_OFF_GAIN
R/W
8'hFF
ALC digital volume gain when alc_ctr_en=1'b0
8'hff: 0dB
8'hfe: -0.375dB
8'hfd: -0.75dB
...
8'h00: -95.625dB (-0.375dB/step)
[12:10]
ALC_RATE_SEL
R/W
3'h1
ALC rate control for sample rate change
3'b001: 48kHz
3'b010: 96kHz
3'b011: 192kHz
3'b011: 44.1kHz
3'b100: 88.2kHz
3'b101: 176.4kHz
[13]
ALC_RC_FAST_EN
R/W
1'b0
ALC force fast recovery control for special cases (window)
1'b0: Disable force fast recovery for special cases
1'b1: Enable force fast recovery for normal use
[15:14]
ALC_COMP_RATIO_SEL R/W
2'b11
ALC DRC compression ratio select control
2'b00: 1:1
2'b01: 1:2
2'b10: 1:4
2'b11: 1:8
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2019-05-15 10:08:03