[AK4675]
■ Input Digital Volume (Manual Mode)
The input digital volume becomes a manual mode when ALC bit is “0”. This mode is used in the case shown below.
1. After exiting reset state, set-up the registers for the ALC operation (ZTM1-0, LMTH1-0 and etc)
2. When the registers for the ALC operation (Limiter period, Recovery period and etc) are changed.
For example, in the case that the change of the sampling frequency.
3. When IVOL is used as a manual volume.
IVL7-0 and IVR7-0 bits set the gain of the volume control (Table 33). When IVOLC bit is “0”, IVL7-0 and IVR7-0 bits
control Lch and Rch volume values independently. When IVOLC bit is “1”, IVL7-0 bits controls both channels. The
IVOL value is changed at zero crossing or timeout. Zero crossing timeout period is set by ZTM1-0 bits. If IVL7-0 or
IVR7-0 bits are written during PMADL=PMADR bits = “0”, IVOL operation starts with the written values at the end of
the ADC initialization cycle after PMADL or PMADR bit is changed to “1”.
IVL7-0 bits
IVR7-0 bits
GAIN (dB)
Step
F1H
F0H
EFH
:
+36.0
+35.625
+35.25
:
92H
91H
90H
:
+0.375
0.0
−0.375
:
0.375dB
(default)
03H
02H
01H
00H
−53.25
−53.625
−54
MUTE
Table 33. Input Digital Volume Setting
■ Side Tone Volume (SVOLA)
The AK4675 has the channel independent side tone volume (5 levels, 6dB step). The volume can be set by the
SVAL/R2-0 bits. The volume is included at mixing path from ALC to 5-band EQ. The output data of ALC is changed
from 0 to –24dB.
SVAL/R2-0
Gain
0dB
0H
1H
2H
3H
4H
(default)
−6dB
−12dB
−18dB
−24dB
N/A
Others
Table 34. Side Tone Volume A Code Table (N/A: Not available)
MS0963-E-00
2008/05
- 81 -
AKM [ ASAHI KASEI MICROSYSTEMS ]
