Hi Gordon, Not a website but some thoughts from my previous experience with PIC stuff. PIC in SO package (especially the low voltage series) is quite sensitive to a wrong PCB design if working in noisy environement. Noisy is different if comes from a relay, stepper, etc or from a PA in a RF frontend. It acts in different mode and is producing different bugs. The most common problem I deal with are traces (routes) below the PIC belly, which are driving signals to drivers (which ever could be those) . Keep a ground continous plane below PIC if this is possible and if you have RF, make enough ground vias between top and bottom (carrying ground on intermediate layers if you have those). The second quite annoying problem is the level of the OSCOUT for XT or HT mode, which some time is on the lower limit of the trigger schmitd input. Missing a few oscillator cycles from time to time is creating random and crazy bugs including errors written in memory. If you have an LDO for PIC supply and the RF stage is sharing the same power, try to separe those using LC filters. If the LDO is not sourcing at least 10% of it's nominal current, you may have problems, there are a lot of LDO's which are unstable on lower currents. good luck, Vasile P.S. see your cure for the problem, however maybe it helps someone else... On 2/9/09, Gordon Williams wrote: > Can anyone point me towards a website or app note where they discuss how > the PIC should be configured for a noisy environment to prevent the PC from > jumping to a random location. > > What I'm looking for is a list of good practices. I'd like to know about > what I should be doing with floating pins, parking EEADR, brownout reset, > waiting after powerup, etc. > > My problem appeared to occur during turnon of the device so maybe there was > a power up glitch or something like that. > > Thanks, > > Gordon Williams > > > > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist