> >>> I have a 16F88 project in need of advise.
> >>> PWM output on CCP1 on RB0 drives a MOSFET to drive a motor.
> >>> RB0/INT interrupt is enabled (on rising edge)
> >>> The interrupt service routine does an adc sample of the current flowi=
ng
> >>> to
> >>> see if there is an overcurrent. (1 ohm resistor in ground side of MOS=
FET)
> >>> This currently drives an LED if an overcurrent.
> >>>
> >>> But cant get my head around a method to tempory collapse the PWM outp=
ut
> >>> voltage if there is an over current condition and allow the PWM perio=
d to
> >>> continue and re-test the current in the next interrupt. Setting RB0 =
=3D 0
> >>> wont
> >>> do it.
> >>>
> >> Hi Dave,
> >>
> >> A few things come to mind. I don't have the 16F88 datasheet in front o=
f
> >> me, so any of these could be wrong. But it is worth checking out:
> >>
> >> 1.Setting TRIS for the pin that PWM is coming out from. I think TRIS i=
s
> >> after the PWM circuitry so this might work.
> >> 2.Setting TMR2 to some number higher than PR2 and stopping it.
> >> 3.Setting CCPR1H to some number.
> >> 4.AND-ing the PWM in hardware with the pin you are driving the LED fro=
m.
> >> 5.Temporarily turning off PWM in CCP1CON.
> >> 6.Setting PR2 to 0? Or does that only work on the next cycle?
> >>
> >> Cheers,
> >>
> >> Bob
> >>
> >
> >
> > In an old project with PIC16F628, just turning off the CCP1CON left the
> > pin at the last state set by the PWM controller. Sometimes it stopped a=
t
> > "1". To turn it off I needed also explicitly clearing the pin.

Hmm, haven't been following this thread, but I wonder if you should really =
be using a small PIC24 or other chip where the CCP is designed for motor co=
ntrol, and has pins that accept over current signal inputs and deal with th=
e CCP output appropriately.

The difference in chip cost is not that large.
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