AK4695 Datasheet, PDF (23/107 Pages) Asahi Kasei Microsystems – 24bit 4ch CODEC with MIC/HP/SPK/LINE-AMP

[AK4695]
■ Audio Interface Format
Four types of data formats are available and selected by setting the DIF1-0 bits (Table 5). In all modes, the serial data is
MSB first, 2’s complement format. Audio interface formats can be used in both master and slave modes. The SDTO is
clocked out on the falling edge (“↓”) of BICK and the SDTI is latched on the rising edge (“↑”) of BICK.
Mode
DIF1
bit
DIF0
bit
PFSEL
bit
SDTO1 (ADC1)
SDTO2 (ADC2)
SDTI (DAC)
BCKI Figure
0
0
0
x
24bit MSB justified 24bit LSB justified  48fs Figure 14
1
0
1
0
1
24bit MSB justified
16bit LSB justified
N/A (Note 44)
 32fs
 32fs
Figure 15
2
1
0
x
24bit MSB justified 24bit MSB justified  48fs Figure 16 (default)
3
1
1
0
I²S Compatible
I²S Compatible
N/A (Note 44)
=32fs or
 48fs
32fs
Figure 17
1
I²S Compatible
 48fs
Note 44. When the path from SDTI to Programmable Filter is selected (PFSEL bit = “1”), do not select 16bit LSB justified
format (DIF1-0 bits = “01”) and I²S Compatible format (DIF1-0 bits = “11” when BCKI=32fs) of SDTI.
Table 5. Audio Interface Format (x: Don’t care, N/A: Not available)
If 24 or 16-bit data, the output of ADC, is converted to an 8-bit data by removing LSB 16 or 8-bit, “-1” data is converted to
“-1” of 8-bit data. And when the DAC playbacks this 8-bit data, “-1” of 8-bit data will be converted to “-65536” or
“-256”of 24 or 16-bit data which is a large offset. This offset can be removed by adding the offset of “32768” or “128” to
24 or 16-bit data, receptively before converting to 8-bit data.
LRCK
01 2
BCKI(64fs)
SDTO1(o)
SDTO2(o)
23 22
8 9 10
16 15 14
20 21
0
31 0 1 2
8 9 10
20 21
23 22
16 15 14
0
SDTI(i)
Don’t Care 23 22
12 11
23:MSB, 0:LSB
Lch Data
1 0 Don’t Care
Figure 14. Mode 0 Timing
23 22
12 11
Rch Data
31 0 1
23
10
MS1463-E-01
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2014/12