|hp20b hacking: SW reset problem|
Message #1 Posted by hugh steers on 12 Apr 2010, 9:50 a.m.
so i finally got around to repurposing a 20b to play chess.
everything was going swimmingly, until i get about 3 moves in and then the unit software resets!
im using the hp20sdk (latest i think). at the start of main, it figures out the startup state and displays it (if you enable the lcd) and i get "SW Reset" when i press ON again.
so i get rid of everything i can find that does this. im disabling the watchdog (damn good idea!) and also various logic to deliberately perform "cpureset".
when i do this, instead of software reset, i get a power reset. when i press on i get "Power Up" and not "Normal Wakeup". this says to me that there is power down. could it be that my batteries are low and cant sustain the output. i notice ServiceBOD handles this, but it performs an Off which should correspond to normal wakeup (or does it?). Getting rid of ServiceBOD does not change anything either.
so im wondering if maybe the unit cant handle it. im running flat out at 36Mhz for say 5 seconds. unfortunately, i haven't got a new set of batteries to test.
are there any other sneaky timers, i might have missed that might do this? disabling the RTC 5 minute timer makes no difference either.