AK4682 Datasheet, PDF (17/43 Pages) Asahi Kasei Microsystems – Multi-channel CODEC with 2Vrms Stereo Selector

[AK4682]
■ De-emphasis Filter
The AK4682 includes the digital de-emphasis filter (tc=50/15μs) by IIR filter. This filter corresponds to three sampling
frequencies (32kHz, 44.1kHz, 48kHz). De-emphasis filter is off in Double speed mode and Quad speed mode. De-
emphasis of each DAC can be set individually by register.
Mode
0
1
2
3
DEM11
(DEM21)
0
0
1
1
DEM10
(DEM20)
0
1
0
1
DEM
44.1kHz
OFF
48kHz
32kHz
(default)
Table 12. De-emphasis control
■ ADC Digital High Pass Filter
The ADC has a digital high pass filter for DC offset cancel. The cut-off frequency of the HPF is 1.0Hz at fs=48kHz and
scales with sampling rate (fs).
■ Audio Serial Interface Format
Each PORTA/B can select independent audio interface format. The TDMA, DIFA1-0 bits control the audio format for
PORTA and support normal mode and TDM128 mode. The DIFB1-0 bits control the audio format for PORTB and
support only normal mode. The default is mode 2. In all modes the serial data is MSB-first, 2’s complement format. The
SDTOB pins are clocked out on the falling edge of BICKB pins and the SDTIA1-0 pins are latched on the rising edge
of BICKA pins.
1. Setting for the PORTA
1-1.Normal mode: TDMA bit = “0” (default)
The TDMA bit = “0” sets the AK4682 audio serial interface format to the normal mode. The DIFA1-0 bits select
following eight serial data format (Table 13).
Mode
0
1
2
3
DIFA1
bit
0
0
1
1
DIFA0
bit
SDTIA1-2
LRCKA
L/R I/O
BICKA
speed I/O
0
20bit, Right justified H/L
I ≥ 48fs I
1
24bit, Right justified H/L
I ≥ 48fs I
0
24bit, Left justified
H/L
I ≥ 48fs I
1
24bit, I²S
L/H
I ≥ 48fs I
Table 13 Audio Interface Format (Normal mode.)
(default)
1-2. TDM 128 mode: TDMA bit = “1”
The TDMA bits = “1” set the AK4682 audio serial interface format to the TDM 128 mode. The four channel serial
data (SDTIA1, 2) is input to the SDTIA1 pin. The data of SDTIA2 pin is not used. The TDM 128 mode is not
available in Quad Speed Mode.
Mode
8
9
10
11
DIFA1
bit
0
0
1
1
DIFA0
SDTIA1-2
LRCKA
BICKA
bit
start I/O speed I/O
0 20bit, Right justified ↑
I 128fs I
1 24bit, Right justified ↑
I 128fs I
0
24bit, Left justified
↑
1
24bit, I²S
↓
I 128fs I
I 128fs I
Table 14. Audio Interface Format (TDM 128 mode.)
(default)
MS0610-E-01
- 17 -
2007/07