AN332
Rev. 0.8
97
Property 0x1301. FM_SOFT_MUTE_SLOPE
Configures attenuation slope during soft mute in dB attenuation per dB SNR below the soft mute SNR threshold.
Soft mute attenuation is the minimum of SMSLOPE x (SMTHR – SNR) and SMATTN. The recommended
SMSLOPE value is CEILING(SMATTN/SMTHR). SMATTN and SMTHR are set via the
FM_SOFT_MUTE_MAX_ATTENUATION and FM_SOFT_MUTE_SNR_THRESHOLD properties. 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
when in power up mode. The default soft mute slope property setting is 2 dB/dB in supported devices. The soft
mute slope is not configurable in Si4704/05/3x-B20 devices (those with FMRX component 2.0) and is 2 dB/dB. The
soft mute slope is not configurable in Si4710/20-A10 devices (those with FMRX component 1.0), and is 0 dB/dB
(disabled).
Available in: Si4704/05/06/3x-C40 and later, Si4740/41/42/43/44/45
Default: 0x0002
Range: 0–63
Property 0x1302. FM_SOFT_MUTE_MAX_ATTENUATION
Sets maximum attenuation during soft mute (dB). Set to 0 to disable 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 when in powerup mode. The
default is 16 dB.
Available in: All except Si4749
Default: 0x0010
Units: dB
Step: 1
Range: 0–31
Bit
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
Name
0
0
0
0
0
0
0
0
SMSLOPE[7:0]
Bit
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
Name
0
0
0
0
0
0
0
0
0
0
0
SMATTN[4:0]
Bit
Name
Function
15:5
Reserved
Always write to 0.
4:0
SMATTN
FM Soft Mute Maximum Attenuation.
Set maximum attenuation during soft mute. If set to 0, then soft mute is disabled. Speci-
fied in units of dB in 1 dB steps (0–31). Default is 16 dB.