STA323W ST Microelectronics, STA323W Datasheet - Page 12

• Manufacturer Part Number: STA323W
• Description: 2.1 High Efficiency Digital Audio System
• Manufacturer: ST Microelectronics

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DataSheet
STA323W
7.1 CONFIGURATION REGISTER A (Address 00h)
7.1.1 Master Clock Select
The STA323W will support sample rates of 32kHz, 44.1kHz, 48Khz, 88.2kHz, and 96kHz. Therefore the
internal clock will be:
■
■
■
The external clock frequency provided to the XTI pin must be a multiple of the input sample frequency (fs).
The correlation between the input clock and the input sample rate is determined by the status of the MCSx
bits and the IR (Input Rate) register bits. The MCSx bits determine the PLL factor generating the internal
clock and the IR bit determines the oversampling ratio used internally.
Table 7. IR and MCS Settings for Input Sample Rate and Clock Rate
7.1.2 Interpolation Ratio Select
The STA323W has variable interpolation (re-sampling) settings such that internal processing and DDX
output rates remain consistent. The first processing block interpolates by either 2 times or 1 time (pass-
through) or provides a down-sample by a factor of 2.
The IR bits determine the re-sampling ratio of this interpolation.
Table 8. IR bit settings as a function of Input Sample Rate
12/41
BIT
32.768Mhz for 32kHz
45.1584Mhz for 44.1khz, 88.2kHz, and 176.4kHz
49.152Mhz for 48kHz, 96kHz, and 192kHz
4...3
BIT
0
1
2
FDRB
4
D7
Input Sample Rate
0
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32, 44.1, 48
176.4, 192
Input Sample Rate Fs (kHz)
fs (kHz)
88.2, 96
R/W
R/W
R/W
R/W
R/W
R/W
TWAB
D6
1
176.4
RST
44.1
88.2
192
32
48
96
1
1
0
RST
00
TWRB
1X
00
01
D5
IR
1
IR (1...0)
NAME
NAME
MCS0
MCS1
MCS2
768fs
384fs
384fs
000
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IR1
D4
Interpolation Ratio Select: Selects internal interpolation ratio based
on input I
0
IR (1,0)
Master Clock Select: Selects the ratio between the input
I
2
00
00
00
01
01
10
10
S sample frequency and the input clock.
512fs
256fs
256fs
001
2
S sample frequency
IR0
D3
0
384fs
192fs
192fs
010
MCS(2..0)
DESCRIPTION
1
MCS2
st
DESCRIPTION
D2
0
Stage Interpolation Ratio
2 times over-sampling
2 times over-sampling
2 times over-sampling
Down-sampling by 2
Down-sampling by 2
256fs
128fs
128fs
011
Pass-Through
Pass-Through
MCS1
D1
1
128fs
64fs
64fs
100
MCS0
576fs
D0
101
1
x
x
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