Modifying fuse bits using Arduino as hardware programmer

Other Hardware 3rd Party Boards
1

Hi,
I was going through AVR fuse bits. I came across the fact that an hardware programmer is needed in order to mod the fuse bits. I have an Atmgea8 on a breadboard which I program using my UNO as an ISP. Is there anyway by which I can mod the fuse bits of that chip using my UNO as a hardware programmer. All suggestions are welcome.
Thanks

2

One method:

You can run that sketch without the SD card if you just want to change fuses.

3

The normal ArduinoISP sketch will enable changing fuses in the target chip. There are numerous tutorials on how to use it, some of which are still current and work. Although I don't think I've seen a tutorial that is specifically about fuse-changing.

4

I did a bit of a research and came across these commands to program the fuse bits:
avrdude -c usbtiny -p m32 -U lfuse:w:0b11101111:m
avrdude -c usbtiny -p m32 -U hfuse:w:0b11001001:m

Of course, the binary number has to be modded as per my requirements . What should I put in instead of 'usbtiny'. I know that m32 has to be changed to reflect the chip I use. So, if I mod the above code, have the ISP sketch on my arduino board, will i be able to use avrdude to program the fuse bits just by entering these commands?

Thanks.

5

Here is a fuse calculator for AVR processors that I book marked that somebody else posted in the past: AVR® Fuse Calculator – The Engbedded Blog

6

I also use an UNO as a programmer, and what I found very useful is a program called Avrdudess. You can get it here:

It is a GUI front end for Avrdude, and allows you to program the fuses, the EEPROM, and the lock bits as well as the flash memory. Very useful.

7

Thanks for the gui version. But I see that there are many 'options' which can be selected. Which ones should I choose? Any suggestions regarding the precautions I should take??

Thanks

8

What should I put in instead of 'usbtiny'.

If you use ArduinoISP use stk500v1

You can see what the IDE use in the programmers.txt. or activate verbose output when doing an upload.

9

Avrdudess settings:

Programmer: Arduino
MCU: Whatever chip you are going to program
Port: The COM port which the Arduino-as-programmer is attached to.
Baud rate: 19200
Bit rate: leave blank
Options: Check "Disable flash erase (-D)" otherwise you risk erasing the bootloader. The other options can be left unchecked.

I think there is a tutorial on the website which covers how to use the program.