Well...  PICs can use timer 0 as a counter.  This is a single bit in a
register to set.  If you require the PIC to tell you when a certain
amount of pulses has appeared, some PICs have a compare function on
timer 1 that enables them to set a flag when a specific amount of
pulses are counted.  Timer 1 is 16 bit, so you can do several turns
without checking the count, and the hardware will tell you when you've
reached you "destination".

-DS


Monday, August 30, 1999, 4:00:22 PM, you wrote:

GC> I want to use a PIC to control a stepper motor and check that it has moved.
GC> The problem that I see is that if I have a 400 step motor and a 1200 encoder
(if one exists)
GC> that every time a send a pulse to my stepper control board to move the motor
 one step I am going to
GC> get back 3 pulses from a encoder. How can I firstly count pulses using a PIC
 and secondly how can I count the three pulses back  when the
GC> PIC is already doing an operation (the stepper pulse signal).
GC> I can not think of how to do this.
GC> I have one hardware type solution and that is to feed the encoders output in
to a counter and then use the pic to read the counter value and
GC> then reset the counter every time but I'm sure that there must be some way t
o do this with the just the pic.
GC> Speed is not a issue with the system as the motor will not be moving very qu
ickly.
GC> I am new to the PIC thing so please don't shout if this is dead easy to do.

GC> Thanks & Regards

GC> Gary




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