i have a standalone ATMega328P with a bootloader (like Arduino UNO) on it,
connected to my raspbarry pi via internal serial port (RX, TX & level shifter).
i want to upload new sketches to ATMega328P by using the raspberry Pi's internal serial port, but i don't know how.
i don't want use ISP, i dont't want to use USB-RS232 converter, i don't want to plug the ATMega328P to ArduinoUNO board temporarily to upload sketches. i want to upload sketches via serial port RX,TX + gpio pin and the bootloader that is already on the ATMega328P.
normally uploading a sketch to ATMega328P via serial port, you need TX, RX for communication and DTR to control the reset line, to activate the bootloader at the right time.
but the Raspberry Pi does not provide a DTR line. so how to manage a reset line to the ATMega328p with the correct timing via one of the GPIO and what software/settings i can use to upload new sketches to my standalone ATMega328P.
the serial connection (RX,TX & level shifter) is done already and is working perfectly.
the only question is the DTR line to manage the reset line and what software and settings are needed.