I buy 0.1uF caps 1000x at a time,so yes there are lots. The PCBs are a special layout for the task and they are double sided PTH, with no ground loops. I've looked at the 5v rail with a pretty good scope and it is quite clean. It is a data logger with cellular modem, and the resets always seem to take place at the same time in the measurement/download cycle so i'm pretty certain it is sw related. Unfortunately the resets are sometimes weeks apart so hard to pin down.
Yo have given me some useful info michael, so i will tomorrow try some of your suggestions. These data loggers are hundreds of miles away from me but I can remote bootload new firmware to them so I'll change one of the more troublesome units tomorrow. Each reset sends me a sms soi can keep track of improvements (or otherwise:) ).
↧