STA320 Datasheet, PDF (8/37 Pages) STMicroelectronics – 2.1 MULTICHANNELS DIGITAL AUDIO PROCESSOR WITH DDTM

STA320
Table 9.
Input Sample Rate
fs (kHz)
32, 44.1, 48
88.2, 96
176.4, 192
IR
000
00
768fs
01
384fs
1X
384fs
001
512fs
256fs
256fs
MCS(2..0)
010
384fs
192fs
192fs
011
256fs
128fs
128fs
100
128fs
64fs
64fs
101
576fs
x
x
5.1.2 Interpolation Ratio Select
BIT
R/W
RST
4..3
R/W
00
NAME
IR(1..0)
DESCRIPTION
Interpolation Ratio Select: Selects internal interpolation ratio
based on input I²S sample frequency
The STA320 has variable interpolation (oversampling) 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 2 times downsample.
The IR bits determine the oversampling ratio of this interpolation.
IR bit settings as a function of Input Sample Rate
Table 10.
Input Sample Rate
Fs (kHz)
32
44.1
48
88.2
96
176.4
192
IR(1,0)
00
00
00
01
01
10
10
1^st Stage Interpolation Ratio
2 times oversampling
2 times oversampling
2 times oversampling
Pass-Through
Pass-Through
2 times oversampling
2 times oversampling
Example: IR = 00, MCS = 011 (Default value):
XTI = 256 x fs = 8.192MHz (fs=32KHz) or 11.2896MHz (fs=44.1KHz) or 12.288MHz (fs=48KHz)
5.1.3 Thermal Warning Recovery Bypass
BIT
R/W
RST
NAME
DESCRIPTION
5
R/W
1
TWRB
Thermal-Warning Recovery Bypass:
0 - Thermal warning Recovery enabled
1 - Thermal warning Recovery disabled
If the Thermal Warning Adjustment is enabled (TWAB=0), then the Thermal Warning Recovery will deter-
mine if the -3dB adjustment is removed when Thermal Warning is negative. If TWRB=0 and TWAB=0,
then when a thermal warning disappears the -3dB adjustment will be removed and the gain will be added
back to the system.
If TWRB=1 and TWAB=0, then when a thermal warning disappears the -3dB adjustment will remain until
TWRB is changed to zero or the device is reset.
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