AK4649 Datasheet, PDF (47/96 Pages) Asahi Kasei Microsystems – 24bit Stereo CODEC with MIC/SPK-AMP

[AK4649]
3. The Volume at ALC Operation
The current volume value at ALC operation is reflected in VOL7-0 bits. It is enable to check the current volume value by
reading the register value of VOL7-0 bits.
VOL7-0bits GAIN (0dB)
F1H
+36.0
F0H
+35.625
EFH
+35.25
:
:
C5H
+19.5
:
:
92H
+0.375
91H
0.0
90H
-0.375
:
:
2H
-53.625
1H
-54.0
0H
MUTE
Table 33. Value of VOL7-0 bits
4. Example of ALC Setting
Table 34 and Table 35 show the examples of the ALC setting for recording and playback path.
Register Name
LMTH1-0
ZELMN
ZTM1-0
WTM2-0
IREF7-0
IVL7-0,
IVR7-0
LMAT1-0
LFST
RGAIN1-0
RFST1-0
ALC1
Comment
fs=8kHz
Data
Operation
Limiter detection Level
01
−4.1dBFS
Limiter zero crossing detection
0
Enable
Zero crossing timeout period
01
32ms
Recovery waiting period
*WTM2-0 bits must be the same value 001
32ms
or larger value than ZTM1-0 bits
Maximum gain at recovery operation E1H
+30dB
Gain of IVOL
E1H
+30dB
Limiter ATT step
00
1 step
Fast Limiter Operation
1
ON
Recovery GAIN step
00
1 step
Fast Recovery Speed
00
4 times
ALC enable
1
Enable
Table 34. Example of the ALC Setting (Recording)
fs=44.1kHz
Data
Operation
01
−4.1dBFS
0
Enable
11
23.2ms
100
46.4ms
E1H
+30dB
E1H
+30dB
00
1 step
1
ON
00
1 step
00
4 times
1
Enable
MS1023-E-01
- 47 -
2010/08