AK4641 Datasheet, PDF (18/51 Pages) Asahi Kasei Microsystems – 16 BIT CODEC WITH BLUETOOTH INTERFACE

ASAHI KASEI
[AK4641]
„ Audio Interface Format of Stereo CODEC
Three types of data formats are available and are selected by setting the DIF1-0 bits. In all modes, the serial data is MSB
first, 2’s complement format. The SDTO is clocked out on the falling edge of BICK and the SDTI is latched on the rising
edge. LRCK and BICK must be input to the AK4641 in slave mode. If 16bit data that ADC of Stereo CODEC outputs is
converted to 8bit data by removing LSB 8bit, “−1” at 16bit data is converted to “−1” at 8bit data. And when the DAC of
Stereo CODEC playbacks this 8bit data, “−1” at 8bit data will be converted to “−256” at 16bit data and this is a large
offset. This offset can be removed by adding the offset of “128” to 16bit data before converting to 8bit data.
Mode
0
1
2
3
DIF1
0
0
1
1
DIF0 SDTO (ADC) SDTI (DAC) BICK
0
MSB justified LSB justified ≥ 32fs
1
MSB justified MSB justified ≥ 32fs
0
I²S
I²S
≥ 32fs
1
N/A
N/A
N/A
Table 5. Audio Interface Format of Stereo CODEC
Figure
Figure 14
Figure 15
Figure 16
-
Default
LRCK
0123
BICK(32fs)
SDTO(o)
15 14 13
9 10 11 12 13 14 15 0 1 2 3
76543210
9 10 11 12 13 14 15 0 1
15
SDTI(i)
15 14 13
0123
BICK(64fs)
SDTO(o)
15 14 13
7 6 5 4 3 2 1 0 15 14 13
15 16 17 18
31 0 1 2 3
10
7 6 5 4 3 2 1 0 15
15 16 17 18
31 0 1
15
SDTI(i)
Don't Care
15:MSB, 0:LSB
15 14
10
Don't Care
15 14
Lch Data
Rch Data
Figure 14. Mode 0 Timing
210
MS0301-E-00
- 18 -
2004/05