AN332 Datasheet, PDF (98/302 Pages) Silicon Laboratories – Si47XX PROGRAMMING GUIDE

AN332
Property 0x1303. FM_SOFT_MUTE_SNR_THRESHOLD
Sets SNR threshold to engage soft mute. Whenever the SNR for a tuned frequency drops below this threshold, the
FM reception will go in soft mute, provided soft mute max attenuation property is non-zero. 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 4 dB.
Available in: All except Si4749
Default: 0x0004
Units: dB
Step: 1
Range: 0–15
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 0
SMTHR[3:0]
Bit
Name
Function
15:4
Reserved Always write to 0.
FM Soft Mute SNR Threshold.
3:0
SMTHR Threshold which will engage soft mute if the SNR falls below this. Specified in units of dB
in 1 dB steps (0–15). Default is 4 dB.
Property 0x1304. FM_SOFT_MUTE_RELEASE_RATE
Sets the soft mute release rate. Smaller values provide slower release and larger values provide faster release.
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 8192 (approximately 8000 dB/s).
Release Rate (dB/s) = RELEASE[14:0]/1.024
Available in: Si4706-C30 and later, Si4740/41/42/43/44/45, Si4704/05/30/31/34/35/84/85-D50 and later
Default: 0x2000
Range: 1–32767
Bit
D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0
Name ⁰
RELEASE[14:0]
98
Rev. 1.0