Hello,

I was wondering if anyone has any good suggestions of how to synchronize
two independ pic chips which control their own motion axis, to achieve a
true linear interpolation.  Today, I use one single 16F877 to do the
coordinated motion of x and y axis, but I would like to move the micro
motion onto their own chips to free up some processing on the main
process.  What I would like to do is that the main process compute the x
and y step and direction, while the two motion processors do the micro
stepping in between.  Let me explain a bit more.  Today, I calculate
position to 0.001 of an inch, I use a timer to precise motion.  Within
the Timer interrupt, I have a routine which does the microstepping need
to move this 0.001 of an inch.  Once the micro stepping has do its full
0.001 movement on both axis, then some flags are cleared to let the main
calculation routine know that it can calculate the next x and y steps.
My problem is that for each micro step, it takes 70 or 80 cycles away,
which are very precious, because once the timer interrupt is completed,
I must be able to recieve new packeted data from a host processor, which
can take a full 200 to 300 cycles.  Because I have a physical time
restraint for motion, must provide at least 10in/sec of motion, I is
possible that I can't get the data from the host fast enough if each
command movement is a vary small distance.  Also, I don't have enough
time to calculate an acceleration profile at these speeds.  So I was
hoping to move the microstepping portion onto a separate pic chip and
just feed them a single step and direction single for the 0.001 movement
along with a single clock clock tick which will control the micro stepps
precisely.  However, I am not sure how to make the synchrozie correctly.
Another solution I would consider would be to have these two independ
chips calculate and cooridate the positions themselves, but I have not
idea where to begin with this.

Regards,

James

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