hello
This is my first time posting on this forum....hoping someone with more knowledge than me can help. I am building a large printer (320x320x330). i have been using a atmega 2560 and ramps 1.4 while waiting for a 32bit arduino due and smartramps. I am using drv8825 drivers. i had reasonable success with the 8bit controller but wanted the 32bit due so when it arrived i installed it right away.....here is the problem i am having.....the due often doesn't boot with power-on but hangs in some form of partial boot state causing a lit but blank screen on the display. This can be fixed with a reset that causes the card to boot properly. When firmware is uploaded the display shows the same lit but blank screen. This is just an annoying glitch that I would easily deal with but there is a second, more serious symptom that concerns me. Whenever the lit but blank screen is happening, my heater for the hotend gets stuck on full power. Within 30 sec if i don't catch it my hotend begins to smoke and I'm stuck cleaning another clogged nozzle and filament throat. I am worried that should there ever be a power failure while printing, a fire could start if the electronics should go into the partial-boot state unnoticed. i am using the programming port on the due and i suspect the partial boot state is part of the 1200baud programming mode....
Anyone know why my hotend gets turned on in this scenario?
I would expect everything to be off until marlin firmware takes over but this doesn't seem to be the case.