My name is Jan Geloen and I live in Belgium. Recently I started building my Prusa printer and got it printing. Since I used 20 Volts to power the generation 6 board my hotend power ressistor failed quickly. I replaced the ressistor and I had the idea to drive a relais with the board heater output so I could use a seperate power supply to power my hotend.
But when I installed a relais I think I fried the output pin on the atmega. (because of a spike "tegen EMK" in dutch ? ) The indicator led is not functioning any more and the output isn't powered when I send a Heater command.
Then I thought of using another pin on the atmega that i'm nog using to drive the heater. I rewired the board ( a few small tweaks) so pin 14 (RS485RE or the PD5 pin) of the atmega is now connected to were pin 15 (Heater or PD6 pin) was connected to.
When i add a bit of code where I set pin 14 manually high I can switch on the heater indicator led so I know my rewiring is working.
Now I want to change the program (I'm running the latest marlin release) so the program switches pin 14 when it normally switches pin 15.