Toshiba TC9314F Manual page 22

Programmable Counter
The programmable counter block consists of a 2-modulus prescaler, 4 bit and 12 bit programmable counters,
and the ports used to control the block.
The programmable counters can be turned on and off by the contents of the reference ports.
1. Programmable Counter Control Ports
These ports control the divisor, division method, and the IF correction (IF offset) for the FM band.
Access the division method and the IF offset using the OUT1 instruction with the operand [C
Access the divisor settings using the OUT1 instruction with the operands [C
writing to bits P0~P15. When the programmable counter data (P12~P15) are set, all the data from P0 to
P15 are updated. Therefore, always access P12~P15 to set the data, even when changing only a portion of
the data.
2. Setting Division Method
The HF and FM bits select the pulse swallow or direct division method.
As the following table shows, there are four methods. Select the appropriate method in accordance with
the frequency band used.
Mode HF FM
LF 0 0
HF 1 0
0 1
FM
1 1
Note 24: n indicates the programmed divisor.
Division Method
Direct division method
(1/15 or 1/16)
Pulse swallow method
(1/15 or 1/16)
Pulse swallow method
1/2 (1/15 or 1/16)
Pulse swallow method
Operating
Example of
Frequency
Reception Band
Range
MW/LW 0.5~10 MHz
SW 1~60 MHz
FM 50~130 MHz
FM 50~130 MHz
22
TC9314F
0H].
N
1H~4H]. Set the divisor by
N
Divisior
Input Pin
(Note 24)
AM n
IN
AM n
IN
FM n
IN
FM 2 n
IN
2003-07-03