AK4122A Datasheet, PDF (27/54 Pages) Asahi Kasei Microsystems – 24-Bit 96kHz SRC with DIR

[AK4122A]
■ Sampling Frequency and Pre-emphasis Detection for DIR
The AK4122A has two methods for detecting sampling frequency for DIR. The sampling frequency is detected by
comparing the recovered clock to the MCLK2 or OMCLK frequency, and the detected frequency is reported on FS3-0
bits. XTL1-0 bits , ICKS1-0 bits and OCKS1-0 bits must be set according to the FSO and MCLK frequencies for the
detection. (Table 16) When XTL1-0 bits = “11”, the sampling frequency is detected by the channel status sampling
frequency information. The detected frequency is reported on FS3-0 bits. The default values of FS3-0 bits are “0001”. In
case of detecting the sampling frequency by MCLK when DIR is used, MCLK (MCLK2 or OMCLK) of selected output
port (PORT2 or PORT3) should be input.
FSO
44.1kHz
48kHz
96kHz
-
XTL1
0
0
1
1
XTL0
0
1
0
1
MCLK2 or OMCLK
ICKS1 / OCKS1 ICKS0 / OCKS0
0
0
0
1
1
0
1
1
0
0
0
1
1
0
1
1
0
0
0
1
1
0
1
1
-
-
Table 16. Reference MCLK Frequency
MCLK Frequency
11.2896MHz
16.9344MHz
22.5792MHz
33.8688MHz
12.288MHz
18.432MHz
24.576MHz
36.864MHz
24.576MHz
36.864MHz
N/A
N/A
Use channel status
(default)
Register Output
FS3 FS2 FS1 FS0
0000
0001
0010
0011
1000
1010
fs
44.1kHz
Reserved
48kHz
32kHz
88.2kHz
96kHz
Except XTL1-0 bit = “11”
Clock comparison
(Note 21)
± 3%
-
± 3%
± 3%
± 3%
± 3%
Table 17. fs Information
XTL1-0 bit = “11”
Consumer Mode
(Note 22)
Professional Mode
Byte3
Bit3,2,1,0
Byte0
Byte4
Bit7,6 Bit6,5,4,3
0000
01
0000
0001
(others)
0000
0010
10
0000
0011
11
0000
(1000)
00
1010
(1010)
00
0010
Note 21. Frequencies in a range of ± 3% are identified as shown in the Table 17. Intermediate frequencies between these
frequencies shown in Table 17 are identified as nearer vale and are shown on FS3-0 bits. FS3-0 bits indicate
“1100”, “1110” or “0001” for the frequencies beyond the range of 32~ 96kHz.
Note 22. In consumer mode, Byte3 Bit3-0 are copied to FS3-0.
The pre-emphasis information is detected and reported on the PEM bit. This information is extracted from channel 1 by
default (CS12 bit = “0”). It can be switched to channel 2 by changing the CS12 bit in the control register.
PEM bit
0
1
Consumer mode Professional mode
Pre-emphasis
Byte0
Byte0
Bit3,4,5
Bit2,3,4
OFF
≠ 0X100
≠ 100
ON
0X100
100
Table 18. PEM Information
MS1076-E-01
- 27 -
2010/05