Changing the boot code to Optiboot on a nano mega328P using a Uno R3

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1

I have a laser controller that uses a nano mega328p, and I need to change the bootloader so I can load grbl 1.1f. I have a Uno R3 and the info on wiring it to the nano which does not have the isp connections. How do I clear the old bootloader and program on the nano, and then how do i write the new Optiboot and GRBL file to the nano? I need written instructions, and all I can find is a poor video on the subject... Thanks, Jim

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NVJims:
How do I clear the old bootloader and program on the nano, and then how do i write the new Optiboot

Follow these instructions:

When you get to this step:

Select the target board from the Tools > Board menu and any other custom Tools menus (e.g. Tools > Processor).

Select Tools > Board > Arduino Uno.

When you get to this step:

Select the appropriate programmer from the Tools > Programmer menu.

Select Tools > Programmer > Arduino as ISP.

Once you have done this, remember to always have Tools > Board > Arduino Uno selected when you use your Nano.

NVJims:
and GRBL file to the nano?

  • Download the latest release of GRBL: https://github.com/gnea/grbl/archive/v1.1h.20190825.zip
  • Unzip the downloaded file.
  • (In the Arduino IDE) File > Open
  • Select the grbl-1.1h.20190825/grbl folder from the unzipped file.
  • File > Examples > grbl > grblUpload
  • Connect your Nano to your computer with a USB cable.
  • Tools > Port > select the port of your Nano. If you don't know which port is your Nano, follow these instructions: Uploading | Troubleshooting Guide For Arduino
  • Sketch > Upload
  • Wait for the upload to finish successfully.
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Thank You very much! This worked and I now have a properly working Nano that thinks that it is a Uno with the Optiboot loader and upgraded grbl.

Jim

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You're welcome. I'm glad to hear it's working now. Enjoy!
Per

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NVJims:
Thank You very much! This worked and I now have a properly working Nano that thinks that it is a Uno with the Optiboot loader and upgraded grbl.

Jim

Nice!

Like a number of other regulars here, I advocate bootloading all '328p-based boards with optiboot (I am sometimes too lazy to do this, but when I do it, I use MiniCore, which has the newer version of optiboot with the trick that lets you write to the flash from the application by calling the bootloader code (only code running in bootloader section is allowed to write to flash). Not because I use that feature, but because, why use the vanilla uno bootloader when there is another version that uses the same amount of flash with more features available?