AK4584_01 Datasheet, PDF (25/53 Pages) Asahi Kasei Microsystems – 24Bit 96kHz Audio CODEC with DIT/DIR

ASAHI KASEI
[AK4584]
„ Sampling Frequency and Pre-emphasis Detection
The AK4584 has two methods for detecting the sampling frequency. The sampling frequency is detected by comparing the
recovered clock to the X’tal oscillator, and the detected frequency is reported on FS3-0 bits. XTL1-0 bits can select
reference X’tal frequency (Table 11). When XTL1-0 bits = “11” and XTALE pin = “L”, X’tal oscillator is stopped and 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 “0000”.
XTL1
0
0
1
1
XTL0
X’tal Frequency
0
11.2896MHz
1
12.288MHz
0
24.576MHz
1
Use channel status
Table 11. Reference X’tal Frequency
Default
Register Output
FS3 FS2 FS1 FS0
0000
0001
0010
0011
1000
1010
1100
1110
fs
44.1kHz
Reserved
48kHz
32kHz
88.2kHz
96kHz
176.4kHz
192kHz
Except XTL1-0 bits=“11”
Clock comparison
± 3%
-
± 3%
± 3%
± 3%
± 3%
± 3%
± 3%
Table 12. fs Information
XTL1-0 bits=“11”
Consumer Mode
(Note 1)
Pro Mode
Byte3
Byte0
Byte4
Bit3,2,1,0
Bit7,6 Bit6,5,4,3
0000
01
0000
0001
(others)
0000
0010
10
0000
0011
11
0000
(1000)
00
1010
(1010)
00
0010
(1100)
00
1011
(1110)
00
0011
Note 1. 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
(default). It can be switched to channel 2 via the CS12 bit in the control register.
PEM bit Pre-emphasis
Byte0
Bit3,4,5
0
OFF
≠ 0X100
1
ON
0X100
Table 13. PEM in Consumer Mode
PEM bit Pre-emphasis
Byte0
Bit2,3,4
0
OFF
≠ 100
1
ON
100
Table 14. PEM in Pro Mode
MS0118-E-00
- 25 -
2001/11