AN543
Rev. 0.9
77
Property 0x0409 FM_SOFT_MUTE_ATTACK_TIME_AGC (Si4754/55/56/57 Only)
When AGC is engaged, the FM_SOFT_MUTE_ATTACK_TIME_AGC property sets maximum time in ms it takes to
mute 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.
Si475x-A20 and earlier, Si475x-A40 and later: This property is not available
Si475x-A30, Default: 120
Units: ms
Property 0x040A FM_SOFT_MUTE_USN_LIMITS
The FM_SOFT_MUTE_USN_LIMITS property sets the values of USN for which audio is minimally and maximally
muted by USN-based soft mute. 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.
Note:
USN will generally be negative under signal conditions where soft mute is desirable. The recommended setting is
0xCEE2 (YMIN = –50, YMAX = –30).
Si475x-A20 and earlier, Si475x-A40 and later: This property is not available
Si475x-A30, Default: 0x060E
Units: ms
FM_SOFT_MUTE_ATTACK_TIME_AGC
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
ATTACK_AGC[15:0]
0x0078
Bit
Name
Function
15:0
ATTACK_AGC[15:0]
Sets the maximum time in ms it takes to unmute the audio. Note that
there will be 16 ms of filter delay for RSSI/SNR metric before softmute
can engage/disengage.Default is 120 ms. Range is 1–32767 ms.
FM_SOFT_MUTE_USN_LIMITS
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
YMIN[7:0]
YMAX[7:0]
0x06
0x0E
Bit
Name
Function
15:8
YMIN[7:0]
Sets the value of USN that causes minimum attenuation for USN-
based soft mute. Default is 6. Range is –127 to 127.
7:0
YMAX[7:0]
Sets the value of USN that causes maximum attenuation for
USN-based soft mute. Default is 14. Range is –127 to 127.
