AN543
Rev. 0.9
73
Property 0x0402 FM_SOFT_MUTE_END_THRESHOLD
The FM_SOFT_MUTE_END_THRESHOLD property sets the SNR threshold in dB at which softmute attenuation
will be set to its maximum value. When the SNR is at this level or lower, the audio attenuation will be set to
FM_SOFT_MUTE_MAX_ATTENUATION. If USE_RSSI is set in the FM_ACF_CONTROL_SOURCE property,
then property 0x0402 refers to the RSSI threshold. If USE_RSSI is not set, this property refers to SNR threshold.
The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set
or read in powerup mode.
Si475x-A40 and earlier, Default: 0
Si475x/5xC-A55, Default: -6
Units:
dB
Property 0x0403 FM_SOFT_MUTE_RELEASE_TIME
The FM_SOFT_MUTE_RELEASE_TIME property sets the maximum time in ms it takes to unmute the audio. The
CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or
read in powerup mode.
Default: 500
Units: ms
FM_SOFT_MUTE_END_THRESHOLD
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
SNR_SMENDTH[7:0]
RSSI_SMENDTH[7:0]
0x00
0xFA
Bit
Name
Function
15:8
SNR_SMENDTH[7:0]
Sets SNR threshold in dB to end the softmute, default is 0.
Range is –127 ~ 127
This field is only available in Si475x/5xC-A55.
7:0
RSSI_SMENDTH[7:0]
Sets the RSSI threshold in dBuV to end the softmute.
Si475x/5xC-A55, Default is –6 dB. Si475x-A40 and earlier, default is 0.
Range is 0 to 15 dB for Si475x-A10, and –127 to127 dB for Si475x-A20 or
later.
FM_SOFT_MUTE_RELEASE_TIME
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RELEASE[15:0]
0x01F4
