AK4683_07 Datasheet, PDF (32/84 Pages) Asahi Kasei Microsystems – Asynchronous Multi-Channel Audio CODEC with DIR/T

[AK4683]
■ De-emphasis Filter
The AK4683 includes the digital de-emphasis filter (tc=50/15μs) by IIR filter. De-emphasis filter is not available in
Double Speed Mode and Quad Speed Mode. This filter corresponds to three sampling frequencies (32kHz, 44.1kHz,
48kHz). De-emphasis of each DAC can be set individually by register.
Mode
0
1
2
3
Sampling Speed
Normal Speed
Normal Speed
Normal Speed
Normal Speed
DEM1
0
0
1
1
DEM0
0
1
0
1
DEM
44.1kHz
OFF
48kHz
32kHz
(default)
Table 30. De-emphasis control
■ 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 TDMA1-0, DIFA1-0 bits control the audio format
for PORTA and support normal mode, TDM256 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 SDTO pins are clocked out on the falling edge of BICK pins and the SDTI pins are latched on
the rising edge of BICK pins.
1. Setting for the PORTA
1-1.Normal mode: TDMA1-0 bit = “00”
The TDMA1-0 bits = “00” set the AK4683 audio serial interface format to the normal mode. The DIFA1-0 bits
select following eight serial data format (Table 31).
Mode
0
1
2
3
4
5
6
7
Master
/slave
DIFA1 DIFA0 SDTOA
SDTIA1-3
LRCKA
I/O
BICKA
I/O
Slave
0
0
24bit, L J 20bit, R J H/L I ≥ 48fs I
Slave
0
Slave
1
Slave
1
Master
0
Master
0
Master
1
Master
1
1
24bit, L J 24bit, R J H/L I ≥ 48fs I
0
24bit, L J 24bit, L J H/L I ≥ 48fs I
1
24bit, I²S 24bit, I²S L/H I ≥ 48fs I
0
24bit, L J 20bit, R J H/L O 64fs O
1
24bit, L J 24bit, R J H/L O 64fs O
0
24bit, L J 24bit, L J H/L O 64fs O
1
24bit, I²S 24bit, I²S L/H O 64fs O
Table 31 Audio Interface Format (Normal mode, L J: Left justified, R J: Right justified.)
(default)
MS0427-E-02
- 32 -
2007/04