AK4649 Datasheet, PDF (53/96 Pages) Asahi Kasei Microsystems – 24bit Stereo CODEC with MIC/SPK-AMP

[AK4649]
■ Output Digital Volume (Manual Mode)
The ALC block becomes output digital volume (manual mode) by setting ALC2 bit to “0” when PMPFIL = PMDAC bits
= “1” and ADCPF bit is “0”. The output digital volume gain is set by the OVL7-0 bit and the OVR7-0 bit (Table 42).
When the OVOLC bit = “1”, the OVL7-0 bits control both Lch and Rch volume levels. When the OVOLC bit = “0”, the
OVL7-0 bits control Lch volume level and the OVR7-0 bits control Rch volume level. When changing the volumes, zero
cross detect is excuted for Lch and Rch individually. The OVOL value is changed at zero crossing or timeout. The zero
crossing timeout period is set by ZTM1-0 bits.
OVL7-0 bits
OVR7-0 bits
GAIN (0dB)
Step
F1H
+36.0
F0H
+35.625
EFH
+35.25
:
:
0.375dB
92H
+0.375
91H
0.0
90H
-0.375
:
:
2H
-53.625
1H
-54.0
0H
MUTE
Table 42. Output Digital Volume Setting
(default)
When writing to the OVL7-0 bits and OVR7-0 bit continuously, the control register should be written in an interval more
than zero crossing timeout. If not, the zero crossing counter is reset at each time and the volume will not be changed. H
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.
■ Output Digital Volume 2
The AK4649 has 4 steps output volume control. Lch and Rch have the same volume values, which are set by DATT1-0
bits as shown in Table 43. This volume control is also available during ALC operation.
DATT1-0bits GAIN (0dB)
Step
0H
0.0
1H
-6.0
6.0dB
2H
-12.0
3H
-18.1
Table 43. Output Digital Volume2 Setting
(default)
MS1023-E-01
- 53 -
2010/08