Bootloader Arduino Uno Rev3

0
votes

I want to load the arduino uno Rev3 boot loader to my 328P chip. I am using USB ASP and Extreme Burner.

I looked at arduino installation folder and there are several Hex files available under "C:\Program Files (x86)\Arduino\hardware\arduino\avr\bootloaders\atmega". I guess I need to make use of ATmegaBOOT_168_atmega328.hex file as the name suggests. Also I understand that the fuse bit I need to select is efuse-0x05 hfuse-0xD6 and lfuse - 0xFF

Can anyone confirm this? Are there any other latest Hex files available?

1
arduino

1 Answers

1
votes

You want the file: optiboot_atmega328.hex

It is in the optiboot folder under bootloaders.

The normal fuses are:

low: FF
high: DE
extended: 05

Optiboot is the 512 byte bootloader, normally installed on the Uno chips.

Bootloader size

As you can see from the datasheet, a high fuse of DE gives a bootloader size of 256 words (that is, 512 bytes).

And the relevant entry in the boards.txt file for the Uno (the standard fuses when you burn the bootloader):

uno.name=Arduino Uno
uno.upload.protocol=arduino
uno.upload.maximum_size=32256
uno.upload.speed=115200
uno.bootloader.low_fuses=0xff
uno.bootloader.high_fuses=0xde
uno.bootloader.extended_fuses=0x05
uno.bootloader.path=optiboot
uno.bootloader.file=optiboot_atmega328.hex
uno.bootloader.unlock_bits=0x3F
uno.bootloader.lock_bits=0x0F
uno.build.mcu=atmega328p
uno.build.f_cpu=16000000L
uno.build.core=arduino
uno.build.variant=standard

This confirms my suggested fuse settings.