Here are the default fuse settings for each Arduino from the boards.txt included with the Arduino development software. To understand more about the fuse settings for your microcontroller, visit [Engbedded’s AVR Fuse Calculator](http://www.engbedded.com/fusecalc/). To write fuse settings, you will need a programmer with this capability. I use [Mighty Ohm’s](http://mightyohm.com) high-voltage rescue shield available [here](http://mightyohm.com/blog/products/hv-rescue-shield-2-x/). ## Arduino Uno

Low Fuse	0xFF
High Fuse	0xDE
Extended Fuse	0x05

## Arduino Duemilanove or Nano w/ ATmega328

Low Fuse	0xFF
High Fuse	0xDA
Extended Fuse	0x05

## Arduino Diecimila, Duemilanove, or Nano w/ ATmega168

Low Fuse	0xFF
High Fuse	0xDD
Extended Fuse	0x00

## Arduino Mega 2560

Low Fuse	0xFF
High Fuse	0xD8
Extended Fuse	0xFD

## Arduino Mega (ATmega1280)

Low Fuse	0xFF
High Fuse	0xDA
Extended Fuse	0xF5

## Arduino Mini

Low Fuse	0xFF
High Fuse	0xDD
Extended Fuse	0x00

## Arduino Fio

Low Fuse	0xFF
High Fuse	0xDA
Extended Fuse	0x05

## Arduino BT w/ ATmega328

Low Fuse	0xFF
High Fuse	0xD8
Extended Fuse	0x05

## Arduino BT w/ ATmega168

Low Fuse	0xFF
High Fuse	0xDD
Extended Fuse	0x00

## LilyPad Arduino w/ ATmega328

Low Fuse	0xFF
High Fuse	0xDA
Extended Fuse	0x05

## LilyPad Arduino w/ ATmega168

Low Fuse	0xE2
High Fuse	0xDD
Extended Fuse	0x00

## Arduino Pro or Pro Mini (5V, 16 MHz) w/ ATmega328

Low Fuse	0xFF
High Fuse	0xDA
Extended Fuse	0x05

## Arduino Pro or Pro Mini (5V, 16 MHz) w/ ATmega168

Low Fuse	0xFF
High Fuse	0xDD
Extended Fuse	0x00

## Arduino Pro or Pro Mini (3.3V, 8 MHz) w/ ATmega328

Low Fuse	0xFF
High Fuse	0xDA
Extended Fuse	0x05

## Arduino Pro or Pro Mini (3.3V, 8 MHz) w/ ATmega168

Low Fuse	0xC6
High Fuse	0xDD
Extended Fuse	0x00

## Arduino NG or older w/ ATmega168

Low Fuse	0xFF
High Fuse	0xDD
Extended Fuse	0x00

## Arduino NG or older w/ ATmega8

Low Fuse	0xDF
High Fuse	0xCA