AK4645AEZ Datasheet, PDF (39/85 Pages) Asahi Kasei Microsystems – Stereo CODEC with MIC/HP-AMP

[AK4645A]
3. ALCಈ࡞ઃఆखॱྫ
Table 28͸ɺ࿥Իύεͷ৔߹ͷALCઃఆྫͰ͢ɻ
Register Name
LMTH1-0
ZELMN
ZTM1-0
WTM2-0
REF7-0
IVL7-0,
IVR7-0
LMAT1-0
RGAIN1-0
RFST1-0
ALC
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 should be the same or 001
32ms
longer data as ZTM1-0 bits.
Maximum gain at recovery operation E1H
+30dB
Gain of IVOL
E1H
+30dB
Limiter ATT step
Recovery GAIN step
Fast Recovery Speed
ALC enable
00
00
00
1
Table 28. ALCઃఆྫ
1 step
1 step
4 times
Enable
fs=44.1kHz
Data
Operation
01
−4.1dBFS
0
Enable
11
23.2ms
011
23.2ms
E1H
+30dB
E1H
+30dB
00
1 step
00
1 step
00
4 times
1
Enable
ALCಈ࡞த͸ɺҎԼͷϏοτ΁ͷมߋΛ͢·͠ࢭېɻ͜ΕΒͷϏοτΛมߋ͢Δ৔߹͸ɺALCಈ࡞Λऴྃ(ALC
bit = “0”·ͨ͸PMADL = PMADR bits = “0”)͔ͯ͠ΒߦͬͯԼ͍͞ɻ
ɾLMTH1-0, LMAT1-0, WTM2-0, ZTM1-0, RGAIN1-0, REF7-0, ZELMN, RFST1-0ͷ֤Ϗοτ
Manual Mode
Example:
Limiter = Zero crossing Enable
Recovery Cycle = 32ms@8kHz
Zero Crossing Timeout Period = 32ms@8kHz
Limiter and Recovery Step = 1
Fast Recovery Speed = 4 step
Gain of IVOL = +30dB
Maximum Gain = +30.0dB
Limiter Detection Level = −4.1dBFS
ALC bit = “1”
WR (ZTM1-0, WTM2-0, RFST1-0)
(1) Addr=06H, Data=14H
WR (REF7-0)
(2) Addr=08H, Data=E1H
WR (IVL/R7-0) ^{* The value of IVOL should be}
the same or smaller than REF’s
WR (RGAIN1, LMTH1)
(3) Addr=09H&0CH, Data=E1H
(4) Addr=0BH, Data=00H
WR (LMAT1-0, RGAIN0, ZELMN, LMTH0; ALC= “1”)
(5) Addr=07H, Data=21H
ALC Operation
Note : WR : Write
Figure 29. ALCಈ࡞ઃఆखॱྫ
MS0986-J-00
- 39 -
2008/07