Hi,

I am implementing a robot control circuit using the PIC16C73.  The motor is
driven by a National LMD18201 H-Bridge that is being fed from the
microcontroller with a PWM pulse train.
I successfully used the Timer2 (TMR2) in conjunction with the CCP1 pin to
generate the pulse.
Now, I need to read "bleeps" or pulses from a digital encoder mounted on the
motor shaft.
I want to be able to count the number of bleeps from the encoder while the
pulse train is being generated by the pic, then shut the motor down.
I tried implementing on pin change interrupt from PORTB pin, so that each
time an interrupt occur, a counter is incremented. But when I debugged the
code, everything was working fine. That is the TMR2 will increment and set
CCP1 at the appropriate timing even if it is in the interrupt service
routine.  I built the circuit and nothing happened. Actually, the pic would
read a series of pulse from the encoder then turn off the pulse train. I
can't find the culprit!

So my questions are:

* how do I read the bleeps from the encoder (digital)?
* Does the TMR2 overflow interrupt is turned off when the code goes in the
ISR causing a o% duty cycle?

Help me please.


Franck


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