Convert from 16f877a to 18f458

[svein97]

Tried to load with the same... wont work! The PIC doesn't start!!!!! Not at all!!
Uses the MPLAB, Osc= HS, osc.sw=disble,pwrup timer=dis,brown....enable 2,4v...WDT enable...wdtPs=128 StackOF=En.

[Dave]

svein97, Are you using a crystal or a resonator? I only use resonators as they are cheaper and have had no problems with them in the last 10 years even at high baud rates. I wonder about your choice of caps to ground at the crystal. They should be no more than about 12pF and should be as close to the VSS pin as possible. I did notice that you are enabling the watchdog timer option. Are you using it within your code? Also I use a 10k resistor to VDD thru a 1N4148 to the RESET/VPP pin on the PIC for the reset circuit as I have provisions for ICSP on my boards. If you have access to an oscilloscope with a 1pF 10x probe look at the OSCout pin and see if it is in oscillation after power is applied. Also make sure that BOTH VSS pins are tied to ground of your supply. LOL

Dave Purola,
N8NTA