fungus:
JoeN:
One of the pins I am using for PWM is also an ISP pin (pin 11). I am guessing that is the issue.Yep.
MOSFET gates are like little capacitors (that's why people refer to MOSFET gate "charge"). Putting a capacitor on the line will ruin high frequency signals.
Thanks. I will move that connection off to a different pin tomorrow. If that doesn't work, I will work some isolators back into the design - I have a bunch from a kit I bought that I have never used. I have some more ideas I want to try and I am not done with this board yet.