PD178016GC-051_15 Datasheet, PDF (41/96 Pages) Renesas Technology Corp – 8-BIT SINGLE-CHIP MICROCONTROLLER WITH BUILT-IN PRESCALER, PLL FREQUENCY SYNTHESIZER, AND IF COUNTER FOR AUTOMOTIVE FM/MW/LW RADIO APPLICATIONS

µPD178016GC-051
3.1.5 AF (Alternative Frequency)
The same contents as those of the RDS station currently being received are used as the code of the frequency
broadcast.
The read AF code is stored into RDS memory.
METHOD A and METHOD B are supported.
If the reception of the RDS station currently being received deteriorates in RDS mode, a search is made for a station
having the same PI code and the frequency is changed (AF operation).
(1) Judging the start of AF operation
(a) AF operation start condition
The AF operation start conditions are listed below.
Signal meter reading
Decode state
Number pending
40 or greater
35 or greater and less than 40
30 or greater and less than 35
15 or greater and less than 30
Less than 15
Range pending
o
o
o
o
o
o
Range A
o
o
o
∆
∆
∆
Range B
o
o
o
o
∆
∆
Range C
×
×
×
×
×
×
o: AF operation does not start.
∆: Single-station/All-station AF operation starts.^Note
×: All-station AF operation starts.
Note Select single-station or all-station AF operation by using initial setting diode AFALL.
(b) Determining the signal meter reading range
Determine the ranges (ranges A, B, and C, and range pending) of the signal meter readings by means of
the following procedure:
<1> Read the signal meter reading from the S • METER pin (pin 3) every 100 ms and calculate the average
of the last five signal meter readings.
<2> After the frequency has been changed, processing <3> below is not performed. The range remains
pending until five signal meter readings have been obtained.
<3> Determine the signal meter reading ranges illustrated below, based on the calculated average of the
signal meter readings.
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