Auto Reset during programming Arduino I know this that when you try to program a pro mini without a DTR pin it will give you a error as the atmega needs to be reset during programming. So I had a doubt why does the microcontroller needs to be reset and clearly at which time you know at which moment does it reset ?
A Reset is necessary to activate the Bootloader and allow programming. Without the DTR signal the Reset button has to be pressed just before starting the upload from the Arduino IDE.