I'm new to the Arduino world so please bear with me. I'm not sure whether the ATmega328 bootloader needs to be burned. What I'm reading is all that needs to be done is plug the board into the computer by USB cable. Then burning the 328 is also mentioned. I appreciate any help.

  • As mentioned, an Arduino style board usually comes with a bootloader in the chip. You can also buy loose chips already programmed with a bootloader at a small price premium. And you can use a working Arduino or similar board as an ISP programmer to burn the bootloader into a chip that doesn't have one, or has a different one that you want, or to directly program a sketch alone without a bootloader. Nov 26 '15 at 22:18
  • You've mentioned Arduino in your first sentence, but then refer to it as ATMega328 and the board. Is it an Arduino board or is it an ATMega Development board? Two similar but different things. I used several versions of ATMega boards since before Arduino was conceived. Those were the days :). For those you would need to burn your own, but anything with Arduino on it would already have it edit: why is it that right after I post the comment, I notice you specifically mention UNO in the title <sigh> It would be highly unlikely a UNO board (even a compatible one) would not have it already
    – Madivad
    Dec 7 '15 at 9:59

If you bought an Arduino Uno the bootloader comes pre-programmed.

"The ATmega328 on the Uno comes preprogrammed with a bootloader that allows you to upload new code to it without the use of an external hardware programmer. It communicates using the original STK500 protocol (reference, C header files)." - from the oficial page.

Might want to take a look at this discussion if you're confused.


You only ever need to burn a bootloader if:

  1. You are building your own "breadboard" Arduino
  2. You have somehow erased the bootloader that is on your Arduino
  3. You have replaced the original chip on the Arduino

The chip that came already inserted into the Arduino board already has the bootloader installed into it.


It depends. If you bought the arduino from most places, it will be already be burned. However, some less reputable sources might not burn it. If the LED on pin 13 blinks when you power on the arduino, that means the bootloader is installed.

  • It would be incredibly rare for an Arduino (even compatible Arduino) board not to have a bootloader installed. I've bought a couple early on that were compatible boards without realising it (I know better now), but they always worked "out of the box". Good point about the LED blinking, I would have tested just by plugging it in and trying to send a sketch to it, so good point right there. And welcome to SE Arduino! :)
    – Madivad
    Dec 7 '15 at 9:54
  • I bought a pack of 15 arduino clones for a class, and roughly half of them had bootloaders. If they are from Arduino.cc they will likely come with the bootloader, but some clones don't.
    – Toms42
    Dec 10 '15 at 21:01

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