SI4720-B20 Datasheet, PDF (39/48 Pages) Silicon Laboratories – BROADCAST FM RADIO TRANSCEIVER FOR PORTABLE APPLICATIONS

Si4720/21-B20
Table 21. Si472x Property Summary (Continued)
Prop
Name
Description
Default
0x0201
0x0202
0x1100
0x1105
0x1106
0x1107
0x1108
0x1200
0x1201
0x1202
0x1203
0x1204
0x1207
REFCLK_FREQ
Sets frequency of reference clock in Hz. The range is
31130 to 34406 Hz, or 0 to disable the AFC. Default is
32768 Hz.
REFCLK_PRESCALE
Sets the prescaler value for RCLK input.
FM_DEEMPHASIS
Sets deemphasis time constant. Default is 75 µs.
Sets RSSI threshold for stereo blend (Full stereo above
FM_BLEND_STEREO_THRESH- threshold, blend below threshold). To force stereo set this
OLD
to 0. To force mono set this to 127. Default value is
49 dBµV.
FM_BLEND_MONO_
THRESHOLD
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. Default value is
30 dBµV.
FM_ANTENNA_INPUT
Selects the antenna type and the pin to which it is con-
nected. (Si4721 only).
FM_MAX_TUNE_
ERROR
Sets the maximum freq error allowed before setting the
AFC rail (AFCRL) indicator. Default value is 30 kHz.
FM_RSQ_INT_
SOURCE
Configures interrupt related to Received Signal Quality
metrics.
FM_RSQ_SNR_HI_
THRESHOLD
Sets high threshold for SNR interrupt.
FM_RSQ_SNR_LO_
THRESHOLD
Sets low threshold for SNR interrupt.
FM_RSQ_RSSI_HI_
THRESHOLD
Sets high threshold for RSSI interrupt.
FM_RSQ_RSSI_LO_
THRESHOLD
Sets low threshold for RSSI interrupt.
FM_RSQ_BLEND_
THRESHOLD
Sets the blend threshold for blend interrupt when bound-
ary is crossed.
0x8000
0x0001
0x0002
0x0031
0x001E
0x0000
0x001E
0x0000
0x007F
0x0000
0x007F
0x0000
0x0081
0x1300
0x1302
0x1303
0x1400
0x1401
FM_SOFT_MUTE_RATE
FM_SOFT_MUTE_
MAX_ATTENUATION
FM_SOFT_MUTE_
SNR_THRESHOLD
FM_SEEK_BAND_
BOTTOM
FM_SEEK_BAND_TOP
Sets the attack and decay rates when entering and leav-
ing soft mute.
Sets maximum attenuation during soft mute (dB). Set to 0
to disable soft mute. Default is 16 dB.
0x0040
0x0010
Sets SNR threshold to engage soft mute. Default is 4 dB. 0x0004
Sets the bottom of the FM band for seek.
Default is 8750 (87.5 MHz).
Sets the top of the FM band for seek.
Default is 10790 (107.9 MHz).
0x222E
0x2A26
0x1402
0x1403
0x1404
FM_SEEK_FREQ_
SPACING
FM_SEEK_TUNE_
SNR_THRESHOLD
FM_SEEK_TUNE_
RSSI_TRESHOLD
Selects frequency spacing for FM seek.
Default value is 10 (100 kHz).
Sets the SNR threshold for a valid FM Seek/Tune.
Default value is 3 dB.
Sets the RSSI threshold for a valid FM Seek/Tune.
Default value is 20 dBµV.
0x000A
0x0003
0x0014
Rev. 1.0
39