Newbie
Joined: 15/11/2015
Location: United KingdomPosts: 35
| Posted: 09:11am 10 Oct 2022 |
Many thanks for all the various responses. I will try to respond in turn to each one:
Mixtel90/Volhout/JohnS/TassyJim: On this chip, pin 70 is just an IO pin. Yes, it is also used for other functions but, until specifically programmed for those functions, it's just an uncommitted pin. However, In an attempt to solve the problem, I physically disconnected the pin (by cutting the trace) from the 40-pin connector I was using to link the two processors, and it made no difference, so I have concluded that this was probably not the problem.
CaptainBoing: Absolutely accept the need for good decoupling and have implemented same. I have also set the Watchdog timer, and at somewhat of a loss to explain why this does not reset the processor when it 'stops'. I can only conclude that the glitch, whatever it is (it only happens about once every couple of months) is sufficient to stop the processor completely so that it cannot reboot itself (not exactly sure how this aspect works!).
TassyJim: Yes, I have the brownout/PSU MCP120 installed. However, see next point...
led-bloon: The system is powered from a LiPo battery which is float-charged continuously from a plug-in PSU, via a LiPo charging regulator circuit. The battery lifetime when the system is idling is several hours, and although power outages of 12 hours are not unknown in this part of Spain(!) I don't think this is a likely cause of the problem.
Since posting the original query, I resorted to a direct connection between the ESP and the reset button via a separate wire. The problem continued! Unfortunately, I don't have my test equipment over here, but I am wondering if there is some strange 'race' effect going on where the application of the power is starting up the ESP fractionally after the MicroMite which is therefore being reset, which is resetting the ESP etc. Sounds odd, but without a scope, I can't check for things like that. I will be taking a parallel system back to UK with me in a week or two and will carry out some more tests - and report my findings!
Finally, I have circumvented the problem in a rather crude, but effective way! I now have a small pushbutton on the box. If I want to power-up from scratch, I hold the button in to disconnect the reset wire while I switch on, then release it, and all is well, and I can reset the MicroMite remotely. It wont solve the problem of the battery running out, though!
Phil