I have designed a board for this mcu to code easy. But ı have problem with the bootloader when the mcu powered on it opens the PB7 for a nearyly 50 miliseconds and this is a very big problem for me because ı connected this pin to a mosfet which controls a parachute system.
Feel free to edit the bootloader, the source is available.
Protect the MOSFET circuit with a resistive pull down, to force it off during the start up high impedance pin state.
It's unlikely that the bootloader does anything with PB7. You should see the same problem on almost any pin.
Yeah i edited but couldn't compile a hex file
I protected but bootloader blink this pin for a led at the start
Why?
Do you need the bootloader at all? You can program it via ISP. I do not see the ISP connector on your board, maybe on the bottom side.
Hi @systemmexe
You might find the Optiboot bootloader easier to compile than the stock "stk500v2" bootloader. Optiboot does now have support for the ATmega2560 microcontroller:
You can set LED_START_FLASHES=0 in the make command to disable the blinking of PB7 by Optiboot.
The excellent "MegaCore" boards platform supports using Optiboot for the ATmega2560, but unfortunately doesn't provide packaged blink-less builds of the bootloaders:
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