Burn bootloader for 3.3V / 8 Mhz on ATMega328P using 5V Nano-clone as ISP

Development Boards Arduino
1

Hi all

I’m still an Arduino / ATMega newbie. Forgive me if this question has been asked here already, but I’ve googled it quite extensively and could not find a clear answer (not for me at least). I just have a question about burning the Arduino bootloader onto an ATMega328P.

I want program an ATMega328P with the Arduino IDE, and use it in a 3.3V circuit, since some of the other modules only work with 3.3V. (I prefer not to use 5V and 3.3V with a level-shifter, in case I mess up some wiring and fry something.) So obviously I need to burn the Arduino bootloader for 3.3V / 8 MHz. However I only have a Nano-clone that works with 5V, that I can use as an ISP.

So my question is simply, if I can burn the bootloader as follows:

  1. Set up the ATMega328P on a breadboard with an 8 MHz resonator (8 MHz crystal oscillators not available here), and power it with 5V from the Nano.

  2. Burn the Arduino bootloader for 3.3V / 8 MHz onto the ATMega328P with the Arduino IDE, using the Nano as an ISP (using 5V for the data signals of course).

This is just to burn the bootloader initially. After that I will use the ATMega328P in a 3.3V circuit with a 3.3V USB-serial converter for uploading and running sketches.

I would assume that this should work, since I assume that the voltages should not matter just for burning the bootloader. However I’m also just a bit confused by the references to the different voltages, and so just want to confirm this as well.

2

This is a complicated thing to do if you’re new to Arduino.

The ATMega328 will run fine at 5 volts or 3.3 so it’s safe to power it at 5 volts while programming a 3.3 volt bootloader. Just make sure you don’t have any 3.3 volt only parts connected while you’re programming.

If you want a ready made solution, we carry the [Arduino Pro and the [Arduino Pro Mini already configured to run at 3.3 volts.](https://www.sparkfun.com/products/11114)](https://www.sparkfun.com/products/10914)