Register description: Sound Terminal compatibility
STA380BW
152/162
DocID024543 Rev 1
7.24
Enhanced zero-detect mute and input level measurement
(address 0x50-0x54, 0x2E, 0x2F and 0x5E)
The STA380BW implements an RMS-based zero-detect function (on serial input interface
data) able to detect in a very reliable way the presence of an input signal, so that the power
bridge outputs can be automatically connected to ground.
When active, the function will mute the output PWM when the input level become less than
“threshold - hysteresis”. Once muted, the PWM will be unmuted when the input level is
detected greater than “thr hysteresis”.
The measured level is then reported (for each input channel) on registers 0x51 - 0x52, 0x53
- 0x54 according to the following equation:
Value_in_dB = 20*Log
10
(Reg_value/(2
16
*0.635))
D7
D6
D5
D4
D3
D2
D1
D0
WTHH
WTHL
FINETH
HSEL[1:0]
ZMTH[2:0]
0
0
0
0
0
1
1
1
D7
D6
D5
D4
D3
D2
D1
D0
RMS_CH0[7:0]
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
D7
D6
D5
D4
D3
D2
D1
D0
RMS_CH0[15:8]
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
D7
D6
D5
D4
D3
D2
D1
D0
RMS_CH1[7:0]
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
D7
D6
D5
D4
D3
D2
D1
D0
RMS_CH1[15:8]
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
Table 167. Zero-detect threshold
ZMTH[2:0]
Equivalent input level (dB)
000
-78
001
-84
010
-90
011
-96
100
-102
101
-108
110
-114
111
-114
Obsolete Product(s) - Obsolete Product(s)