cswd

Joy - I'm beginning to hate PICs after all the trouble I've seen with recent ones. I wish I'd stuck with big old Z80s and EPROMs/SRAM/discrete on large chunks of stripboard eating tons of juice. Can't use a 452 as my programmer doesn't support it (thank you Microchip!). My current problem is getting the oscillators to stay stable on my dev board. I've tried just about every cap value between 2.2pF and 100pF and the oscs die randomly. The XTAL is a known good one (10MHz). The damn thing just dies after about a minute - it's not the WDT which is disabled and the IRQ routine just does an RETFIE straight away. It's got to be stray capacitance as if i stick my scope (philips pm3217) near it or my finger it dies too (meaning i can't even check the osc drive waveform to make sure it's stable). I'm a VLSI guy by trade - stray capacitance is my middle name - so this should not be a problem!! Awful pieces of crap!

Anyone know if using a 18F4520 works instead of the 18F452? The 452 is obsolete now according to Microchip.com and the 4520 has replaced it and is feature compatible (plus my programmer - pickkit2 - only likes the 4520). I've ordered 3x 18F4520 anyway as they're free from samples.microchip.com ;)