AN332
84
Confidential Rev. 0.2
Property 0x1106. FM_BLEND_MONO_THRESHOLD (Not applicable for Si4706/40/41/49)
Sets RSSI threshold for mono blend (Full mono below threshold, blend above threshold). To force stereo, set this
to 0. To force mono, set this to 127. 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 30 dBµV.
Default: 0x001E
Units: dBµV
Step: 1
Range: 0–127
Property 0x1107. FM_ANTENNA_INPUT (Si4704/05/06/20/21 Only)
Selects what type of antenna and what pin it is connected to. Default is 0 which means the antenna used is a
headphone (long) antenna and it is connected to the FMI pin. Setting the FMTXO bit to 1 means that the antenna
used is an embedded (short) antenna and it is connected to the TXO/LPI pin.
Default: 0x0000
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
MONOTHRESH[6:0]
Bit
Name
Function
15:7
Reserved
Always write to 0.
6:0
MONOTHRESH
FM Blend Mono Threshold.
RSSI threshold below which the audio output goes into full mono mode. Above this
threshold the audio output is in blend or full stereo. Specified in units of dBµV in 1 dB
steps (0–127). Default is 30 dBµV.
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
0
0
0
FMTXO
Bit
Name
Function
15:1
Reserved
Always write to 0
0
FMTXO
Selects what type of antenna and which pin it is connected to:
0 = Use FMI pin for headphone (long) antenna
1 = Use TXO/LPI pin for embedded (short) antenna