PWM / Motor Control Update

As it turns out, the ubiquitous little servo motors that seem to be everywhere are more sensitive to the PWM signal being sent to them than I originally thought.  At first I thought that as long as you were sending them a pulse that was the appropriate length that the frequency did not matter much, but try as I might, I could not get my servo to work with a 32.7ms delay (thats the time between TOIs on the HC11).  It actually required a very precise 20ms period before I could get my servo to do anything slam itself into the left hand side of its range.  Perhaps my servo is particularly picky, or perhaps it wasn’t the period at all and I just happened to change something else that made it work at the same time as I changed the period to 20ms (it was kind of one of those “I’ll do anything to get this damn thing to work” moments, so I was flailing around changing anything I could think of, all at the same time).

At any rate, I did eventually get the HC11 to control the servo motor based on the ADC input reading the pot on the evaluation board.  I still have a lot of tuning to do.  I am currently splitting up the functions and trying to work out a good way to organize things so that I can keep the PWM stuff in a separate file and link it to the main program.  I also need to calibrate the range of the servo, but that will come later.

Here is the code: