[MPaulHolmes]

The only reason I like the attiny is, the very high impedance 62.5kHz signal is very short and never leaves the PCB, which has a ground plane running right under the high frequency signals. I've never had a problem getting the isolated supplies working using it. The dspic has a few interrupts running. Could it be that the 62.5kHz timer sometimes gets put on hold due to other interrupts? With the ATTiny It's an identical number of 1MHz cycles on as off at 1MHz. So, any variation would only be in the difference between turnoff and turnon time of ports. The inverter chip would work I bet, but I would just be worried that you would really have a perfectly consistent 62.5KHz signal due to interrupt issues. I know you could make the 62.5kHz timer the highest priority. maybe that could eliminate jitter.