Microcontroller turning off at random

[chris414]

I'm sure it's a simple thing, but what could the reason be for my microcontroller (PIC18F2550) randomly turning on and off? It seems to happen every time i touch one of the rails which makes me think its something to do with the supply voltage...? I'm using an ATX power supply from a computer with LM317 voltage regulator.

Is there not an "enable" pin that I'm missing out?

 

[blueroomelectronics]

Post your schematic

 

[smanches]

Do you have every pin connected to something? If you have floating pins, they can change state due to the electrical interference from you hand.

Schematic?

 

[gabeNC]

Or no bypass caps. I've learned that lesson but we can only speculate since the OP hasn't posted his circuit.

 

[ronsimpson]

reset pin floating.
any pin that can cause an interupt floading.
You OSC may not be stable.

 

[Oznog]

Floating input pins alone for normal inputs will NOT cause resets. Not unless there's a piece of code which will do something funky and cause a reset when there's a 1 or 0 on one of those pins.

Low Voltage Programming enabled and leaving the LVP pins floating will. Had that prob...