Change the fuses of an Arduino Uno (can an Arduino Uno change its own fuses?)

Question

For now, I'm using an Arduino Uno alone including its 328p (no other external chip to program).

I would like to change its fuses to internal 8 Mhz clock (because then I'll move the 328p out of the Arduino Uno), and for simplicity I'd like to do it from Arduino IDE.

Here is what I tried:

• I created a new entry in boards.txt copy-pasted from Uno, fuses modified, like this:

  atmega328p.name=Atmega328p
  atmega328p.upload.tool=avrdude
  atmega328p.upload.protocol=arduino
  atmega328p.upload.maximum_size=32256
  atmega328p.upload.maximum_data_size=2048
  atmega328p.upload.speed=115200
  
  atmega328p.bootloader.tool=avrdude
  atmega328p.bootloader.low_fuses=0x62
  atmega328p.bootloader.high_fuses=0xD9
  atmega328p.bootloader.extended_fuses=0xFF
  atmega328p.bootloader.unlock_bits=0x3F
  atmega328p.bootloader.lock_bits=0x0F
  atmega328p.bootloader.file=optiboot/optiboot_atmega328.hex
  
  atmega328p.build.mcu=atmega328p
  atmega328p.build.f_cpu=8000000L
  atmega328p.build.board=AVR_UNO
  atmega328p.build.core=arduino
  atmega328p.build.variant=standard
  

• I selected this board in Tools > Board: Atmega328p

• I tried to Upload any sketch (and not Upload with programmer since I have no other chip connected to the Arduino Uno), hoping it would modify the fuses during the (successful) Upload process.

I think it didn't work (when I move the 328p outside of the Uno it doesn't work).

How can I change the fuses for an Arduino Uno directly from Arduino IDE, to enable internal 8 Mhz clock?

---

PS: "Tools > Burn Bootloader" does not succeed, but I think this is normal, since there is just the Arduino Uno, and no other chip / nothing to use as a "Programmer":

avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 1 of 10: not in sync: resp=0x03

Answer 1

You need a programmer to burn fuses. If you have another arduino then you can use the Arduino as ISP example sketch in the IDE. You can't burn fuses just using the USB cable like you upload code with. The only reason that can talk to the chip at all is because there is another chip to convert it to serial and a bootloader on the 328P to allow it to upload code via serial.

Answer 2

As mentioned in the other answer, it seems that it's not possible for an Arduino Uno to change its own fuses.

So here is how I did:

• I used a Nano (loaded with "Arduino as ISP") as programmer for the Uno with this classical wiring (except that in my case, the left board, the programmer, is a Nano):

• I added this to boards.txt (source here):

  ##############################################################
  atmega328bb.name=ATmega328 on a breadboard (8 MHz internal clock)
  atmega328bb.upload.protocol=arduino
  atmega328bb.upload.maximum_size=30720
  atmega328bb.upload.maximum_data_size=2048
  atmega328bb.upload.speed=57600
  atmega328bb.upload.tool=avrdude
  atmega328bb.bootloader.tool=arduino:avrdude
  atmega328bb.bootloader.low_fuses=0xE2
  atmega328bb.bootloader.high_fuses=0xDA
  atmega328bb.bootloader.extended_fuses=0x05
  atmega328bb.bootloader.file=atmega/ATmegaBOOT_168_atmega328_pro_8MHz.hex
  atmega328bb.bootloader.unlock_bits=0x3F
  atmega328bb.bootloader.lock_bits=0x0F
  atmega328bb.build.mcu=atmega328p
  atmega328bb.build.f_cpu=8000000L
  atmega328bb.build.core=arduino
  atmega328bb.build.variant=standard
  atmega328bb.build.board=AVR_BARE
  

• I used "Programmer: Arduino as ISP", then "Burn bootloader" then "Upload with programmer" with any sketch.

• Then the fuses are programmed to Internal 8 Mhz, and we can take the ATmega328p out of the Uno and move it on a breadboard! Working now :)

Answer 3

This is technically possible, but tricky.

First you'd have to wire up the Arduino with some jumpers in such a way that the 328P can use its ICSP header to reprogram the 16U2/8U2 via that chips own header. With the right custom firmware in place you could then re-wire the board so that the 16U2 changes the fuses of the 328P upon boot and reuploads the firmware before switching into its usual function. Then it's just a matter of having the 328P reprogram the 16U2 with the original DFU firmware, and presto! An Arduino that changed its own fuses!

If you just need to change the fuses without a ICSP programmer then that can be done by just programming the 16U2 chip directly through its USB port (although technically that doesn't qualify as the Uno "programming itself").