sta339bw STMicroelectronics, sta339bw Datasheet - Page 28

• Manufacturer Part Number: sta339bw
• Description: 2.1-channel High-efficiency Digital Audio System
• Manufacturer: STMicroelectronics

Register description
6.1.2
6.1.3
6.1.4
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Interpolation ratio select
Table 12.
The STA339BW has variable interpolation (oversampling) settings such that internal
processing and FFX 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
oversampling ratio of this interpolation is determined by the IR bits.
Table 13.
Thermal warning recovery bypass
Table 14.
If the thermal warning adjustment is enabled (TWAB = 0), then the thermal warning
recovery determines if the -3 dB output limit is removed when thermal warning is negative.
If TWRB = 0 and TWAB = 0, then when a thermal warning disappears the -3 dB output limit
is removed and the gain is added back to the system. If TWRB = 1 and TWAB = 0, then
when a thermal warning disappears the -3 dB output limit remains until TWRB is changed to
zero or the device is reset.
Thermal warning adjustment bypass
Table 15.
The on-chip STA339BW power output block provides feedback to the digital controller using
inputs to the power control block. Input TWARN is used to indicate a thermal warning
4:3
32
44.1
48
88.2
96
176.4
192
5
6
Bit
Bit
Bit
Input sample rate fs (kHz)
R/W
R/W
R/W
R/W
R/W
R/W
Internal interpolation ratio
IR bit settings as a function of input sample rate
Thermal warning recovery bypass
Thermal warning adjustment bypass
1
1
00
RST
RST
RST
TWRB
TWAB
IR [1:0]
Name
Doc ID 15251 Rev 4
Name
Name
00
00
00
01
01
10
10
IR
Selects internal interpolation ratio based on input I
sample frequency
2 times oversampling
2 times oversampling
2 times oversampling
Pass-through
Pass-through
2 times downsampling
2 times downsampling
0: Thermal warning recovery enabled
1: Thermal warning recovery disabled
0: Thermal warning adjustment enabled
1: Thermal warning adjustment disabled
1st stage interpolation ratio
Description
Description
Description
STA339BW
2
S