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Rev. 0.8
FM_BLEND_MULTIPATH_MONO_THRESHOLD (0x1809) = 60 (-D60)
FM_BLEND_MULTIPATH_ATTACK_RATE (0x180A) = 4000 (-D60)
FM_BLEND_MULTIPATH_RELEASE_RATE (0x180B) = 40 (-D60)
In -B20 and -C40, FM stereo blend is only determined by RSSI based on blend thresholds set in 0x1105 and
0x1106. In -D60 devices, a series of advanced blend properties have been added to improve the user experience
under dynamic signal conditions. To accommodate for this change, RSSI based threshold properties were
relocated respectively to properties 0x1800 and 0x1801. 0x1800 and 0x1801 have the same default values as
0x1105 and 0x1106.
Additional advanced blend features include stereo blending based on SNR and multipath thresholds. For each set
of thresholds, separate blend attack (into mono) and release (into stereo) rates may be set. Each of the factors is
independently evaluated, and any may trigger a blend into mono at its given threshold and rate. To remove any of
the advanced blend factors from consideration; set the corresponding blend thresholds to min value of 0 for SNR
based blend (0x1804/0x1805), and set the corresponding blend thresholds to max value of 100 for multipath based
blend (0x1808/0x1809).
FM Commands
Some parameters and returned values are only applicable to -D60 parts. These are: multipath indicator returned by
the FM_TUNE_STATUS command and the MULTIPATH_DETECT_HIGH and MULTIPATH_DETECT_LOW
parameters of the FM_RSQ_STATUS command.
In -C40 and -D60 devices, the RDSSYNC bit of the response to an FM_RDS_STATUS command may be
incorrectly set. A patch is available only for -D60 devices.