WM9714L_06 WOLFSON [Wolfson Microelectronics plc], WM9714L_06 Datasheet - Page 28

• Manufacturer Part Number: WM9714L_06
• Description: AC 97 Audio CODEC
• Manufacturer: WOLFSON [Wolfson Microelectronics plc]

WM9714L
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When one ADC channel is unused, the peak detector disregards that channel. The ALC function can
also operate when the two ADC outputs are mixed to mono in the digital domain, but not if they are
mixed to mono in the analogue domain, before entering the ADCs.
Table 14 ALC Control
62h
ALC / Noise
Gate Control
60h
ALC Control
REGISTER
ADDRESS
15:14
13:11
10:9
15:12
11:8
7:4
3:0
BIT
ALCSEL
MAXGAIN
ZCTIMEOUT
ALCL
HLD
DCY
ATK
LABEL
00
(OFF)
111
(+30dB)
11
1011
(-12dB)
0000
(0ms)
0011
(192ms)
0010
(24ms)
DEFAULT
ALC function select
00 = ALC off (PGA gain set by register)
01 = Right channel only
10 = Left channel only
11 = Stereo (PGA registers unused)
PGA gain limit for ALC
111 = +30dB
110 = +24dB
….(6dB steps)
001 = -6dB
000 = -12dB
Programmable zero cross timeout (delay
for 12.288MHz BITCLK):
11: 2^17 * tbitclk (10.67 ms)
10: 2^16 * tbitclk (5.33 ms)
01: 2^15 * tbitclk (2.67 ms)
00: 2^14 * tbitclk (1.33 ms)
ALC target – sets signal level at ADC
input
0000 = -28.5dB FS
0001 = -27.0dB FS
… (1.5dB steps)
1110 = -7.5dB FS
1111 = -6dB FS
ALC hold time before gain is increased.
0000 = 0ms
0001 = 2.67ms
0010 = 5.33ms
… (time doubles with every step)
1111 = 43.691s
ALC decay (gain ramp-up) time
0000 = 24ms
0001 = 48ms
0010 = 96ms
… (time doubles with every step)
1010 or higher = 24.58s
ALC attack (gain ramp-down) time
0000 = 6ms
0001 = 12ms
0010 = 24ms
… (time doubles with every step)
1010 or higher = 6.14s
DESCRIPTION
PP Rev 3.0 June 2006
Pre-Production
28