I want to get an ATMega328 off of the Digi-Key, and use it like an Arduino (without requiring the whole Arduino board).

When it comes to programming, do I need to do anything special like burn the bootloader onto it or something like that?

I want to use the Arduino IDE to program it.

  • The processor for a home made Arduino is an ATMEGA328P. Note the P at the end or you may encounter invalid signature errors when programming it. There is an unfortunate terminology problem with "burn bootloader" in the Arduino IDE. You need to use "burn bootloader" to set the processor fuses even if you don't want a bootloader. Finally, check the stock level of the ATmega328P at Digikey in advance to avoid disappointment.
    – 6v6gt
    Aug 29, 2022 at 4:15

2 Answers 2


At the risk of having my answer closed as "link only" I want to tell you that I have a page describing how to make an Atmega328P into an Arduino-compatible board.

There is far too much detail to post here, but once you have installed your processor with a resistor and a couple of decoupling capacitors you can use another Arduino to burn the bootloader.

Burning the bootloader

Once you have done that you can use an FTDI cable to program your new Arduino-compatible from the Arduino IDE. The cable would be hooked up like this:

Programming with FTDI cable

Now you can program the chip just using the IDE as if it was a "real" Arduino.


No, you do NOT need to burn the bootloader. But depending on your equipment and programing habits you may want to.
The bootloader used by Arduino (which is known by the name 'optiboot') is used to allow to program the microcontroller via serial interface. If you want to program your microcontroler this way, then you need the bootloader. Otherwise you will need a programmer for In-System-Programing that uses the SPI interface like Atmel AVRISP MKII, any cheap clone like USBtinyISP or any regular Arduino with ArduinoISP flashed on it.

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