Pic reset and following lock up problem

[skimask]

The late modle GM HEI coils may in fact be 12v, I do not know for sure

They are straight up 12V. The early coils for points type distributors also had an 'S' terminal on the starter. You hit the key, the coil gets it's juice direct from the battery since the starter is already killing off some voltage. You release the key, the coil gets juice thru the ballast resistor, knocking the volts down to 7-ish like you said. Keeps the coil from overheating.
The HEI coils can run 12V because of the inherent variable dwell (not to mention they're designed for it), whereas the older coils for points had a more-or-less constant dwell.

What's really fun is to hook a coil up to an 'old-school' turn signal flasher and a single spark plug gapped to about 1/4"+ and zapping your friends.

[zerosvarka]

Hi Everyone,

I use Usb to Serial adaptor to communicate between Pic and PC. I noticed that when I fire the coil without the high tension lead and spark plug (the spark jumps to the secondary earth wire that goes to the battery negative terminal) my Usb to Serial adaptor locks up and I have to reconnect it on the usb side. But if I communicate with stand alone Pic powered from a separate power supply and trigger the coil from my circuit everything works fine.

I tried to Debug Status and Pcon registers to determine the cause of the reset. When I disconnect power or ground the MCLR pin it doesn’t change the registers. I attached the code. Can someone have a look at it please