Engbedded Atmel AVR® Fuse Calculator

Device selection

Select the AVR device type you want to configure. When changing this setting, default fuse settings will automatically be applied. Presets (hexadecimal representation of the fuse settings) can be reviewed and even be set in the last form at the bottom of this page.

AVR part name:    (141 parts currently listed)

Feature configuration

This allows easy configuration of your AVR device. All changes will be applied instantly.


Manual fuse bits configuration

This table allows reviewing and direct editing of the AVR fuse bits. All changes will be applied instantly.
Note: means unprogrammed (1); means programmed (0).

Bit LowHighExtended
Divide clock by 8

External Reset disable
Clock Output Enable

DebugWIRE Enable
Select start-up time

Enable Serial Program and Data Downloading
Select start-up time

Watchdog Timer always on
Select Clock source

EEPROM memory is preserved through the Chip Erase
Select Clock source

Brown-out Detector trigger level
Select Clock source

Brown-out Detector trigger level
Select Clock source

Brown-out Detector trigger level

Self-Programming Enable

Current settings

These fields show the actual hexadecimal representation of the fuse settings from above. These are the values you have to program into your AVR device. Optionally, you may fill in the numerical values yourself to preset the configuration to these values. Changes in the value fields are applied instantly (taking away the focus)!

LowHighExtendedAction AVRDUDE arguments

Apply manual changes to the values on the left side, or load factory default values for the selected device.

-U lfuse:w:0x62:m -U hfuse:w:0xdf:m -U efuse:w:0xff:m

Select (try triple-click) and copy-and-paste this option string into your avrdude command line. You may specify multiple -U arguments within one call of avrdude.

* Note that some numerical values refer to fuses containing undefined bits (set to '1' here). Depending on the target device these fuse bits will be read either as '0' or '1'. Verification errors will occur if the values are read back with undefined bits set to '0'. Everything is fine if the values read from the device are either the same as programmed, or the following values (undefined set to '0'): Extended: 0x01.


All information based on database ATtiny45.xml build 134.
Applied patches: CKSEL3 default value (Mark Haemmerling)

No responsibility is taken for the correctness of the presented information.
Copyright © 2006-2014 Mark Hämmerling. This is a free service of Engbedded. Use at your own risk.
User interface version: 0.9.2.

If you find bugs in the user interface or the database backend(s), please report them.