AK4950 Datasheet, PDF (54/106 Pages) Asahi Kasei Microsystems – 24bit Stereo CODEC with MIC/SPK/Cap-less VIDEO-AMP & mini DSP

[AK4950]
■ Input Digital Volume (Manual Mode)
The input digital volume becomes manual mode at ALC bit = “0” when ADCPF bit =“1”. This mode is used in the case
shown below.
1. After exiting reset state, when setting up the registers for ALC operation (LMTH and etc.)
2. When the registers for ALC operation (Limiter period, Recovery period and etc.) are changed.
For example; when the sampling frequency is changed.
3. When IVOL is used as a manual volume control.
IVL7-0 and IVR7-0 bits set the gain of the volume control (Table 37). When the IVOL value is changed, the transition is
executed via soft changes. The transition time between set values is 10ms@fs =44.1kHz. L and R channel volumes are set
individually by IVL7-0 and IVR7-0 bits when IVOLC bit = “0”. IVL7-0 bits control both L and R channel 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 37. 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 changing ADCPF bit, the volume value is changed to OVL/R(IVL/R) from IVL/R(OVL/R). The switching noise
can be reduced by setting into soft mute sate (SMUTE bit = “1”) before changing ADCPF bit.
MS1320-E-00
- 54 -
2011/10