screening / glitchy operation - sanity check

[Jonathan]

Can't you just connect the button to one of the interrupt-on-change pins and make that a high priority interrupt? That will allow you to break from the delay function and stop the motor. You could also use a timer based interrupt instead of the delay - just set the timer pre-scalars so it overflows every 5ms (or whatever you need) and enable the relevant interrupt bit. That way the PIC can do something useful instead of twiddling it's thumbs for 5ms.

By stop you presumably mean increment PR2 to decelerate the motor in a controlled manner, otherwise you risk loosing synchronization particularly if the load inertia or speed are high. If you want the motion to be smoother, then instead of using constant acceleration you could set the derivative of acceleration ('jerk') to be an s-curve like tanh(x):



To do that, either use the (approximate) equation for that function or a lookup table to calculate the required PR2 value each time the timer interrupt occurs. I don't know what the purpose of this project is so not sure if this is necessary, but it's more interesting ;)