AK4649 Datasheet, PDF (52/96 Pages) Asahi Kasei Microsystems – 24bit Stereo CODEC with MIC/SPK-AMP

[AK4649]
■ Input Digital Volume (Manual Mode)
The input digital volume becomes manual mode at ALC1 bit = “0” when ADCPF bit =“1”. This mode is used in the case
shown below.
1. After exiting reset state, set-up the registers for ALC operation (ZTM1-0, LMTH and etc)
2. When the registers for ALC operation (Limiter period, Recovery period and etc) are changed.
For example; when the change of the sampling frequency.
3. When IVOL is used as a manual volume control.
IVL7-0 and IVR7-0 bits set the gain of the volume control (Table 41). The IVOL value is changed at zero crossing or
timeout. The zero crossing timeout period is set by ZTM1-0 bits. Lch and Rch volumes are set individually by IVL7-0 and
IVR7-0 bits when IVOLC bit = “0”. IVL7-0 bits control both Lch and Rch volumes together when IVOLC bit = “1”.
IVL7-0 bits
IVR7-0 bits
GAIN (dB)
Step
F1H
+36.0
F0H
+35.625
EFH
+35.25
:
:
E2H
+30.375
E1H
+30.0
0.375dB
E0H
+29.625
:
:
03H
−53.25
02H
−53.625
01H
−54
00H
MUTE
Table 41. Input Digital Volume Setting
(default)
If IVL7-0 or IVR7-0 bits are written during PMPFIL bit = “0”, IVOL operation starts with the written values after
PMPFIL bit is changed to “1”.
When writing to IVOL7-0 bits continually, take an interval of zero crossing timeout period or more. If not, the zero
crossing counter is reset at each time and the volume will not be changed. However, when writing the same register values
as the previous time, the zero crossing counter will not be reset, so that it could be written in an interval less than zero
crossing timeout.
MS1023-E-01
- 52 -
2010/08