My program flow is just like: start up, connect wifi, read data and send data, deep sleep 1 minute and start up again.
Maybe one day or more, it will be corrupt without any signs at all , it is indeed dead and I can not wake it up even I repower it.
when I connect the serials, it only print some unrecognizable characters (I tried lots of baud rate)
The only way I can do is flash it , and it will work properly again.
I do not know how to debug it, because there is nothing to find out why, anyone has an idea?
thanks very much.