I'm trying to control a PMDC motor using PIC16F870. It can
regulate speed using PWM mode of the CCP module. The hall
effect sensor outputs a train of pulses, frequency of these
proportional to the motor speed. Since the CCP module is 
being used in PWM mode, I cannot use it in capture mode to 
time these pulses.

To do so, the alternative that I can think of is to use
RB0/INT. The rising/falling edges of the pulses from the
sensor act as external triggers on RB0/INT pin. The
interrupts so generated can be timed by TMR0 (which is
running in the background).

Kindly comment on this solution. Or are there other better
ways of doing it?

Hardware details:
Processor = PIC16F870 @ 4MHz
PORTA<1> reads a pot for speed setting.
PORTA<5:2> are free pins.
PORTB is free.
PORTC<7:4> are connected to LCD data lines.
PORTC<1:0> are to LCD control lines.
PORTC<2> is PWM output.
PORTC<3> is flashing LED.

Peace,
Mohit.


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