fastboot-made-easy

Peter Dannegger's fastboot (https://www.mikrocontroller.net/articles/AVR_Bootloader_FastBoot_von_Peter_Dannegger) is a fantastic serial bootloader for (any!?) AVR microcontroller. I love it and use it all the time.

It lets you upload new code to your microcontroller project with the very same serial-USB cable that you're using for printf() debugging anyway. How's that for convenient?

Outstanding features include:

• USART autobauding
• Reasonably sized (around 512 KB)
• Works on Tiny13 to Mega328 and beyond (AFAIK)
• One-wire mode (with additional hardware)
• Smart flashing software lets you use every last byte of flash memory for your code.
• Very fast. So fast, it's in the name.
• It's really old. It's been battle-tested. It works.

Actually compiling fastboot for any given chip / port / CPU speed combo involves editing a Makefile each time. And recently (sometime in 2015?) the compile procedure went broken, due to upstream changes in GCC, but whatevers. So I ended up re-writing the compile frontend for my own purposes, and thought I'd share.

So what I've done here is to fix the get_avr_arch.sh file, streamline the build process, add an interactive frontend, and add pre-built binaries for all the chip X pin combinations that I use with any frequency. There are also flash / test scripts for each processor which:

1. Upload the correct bootloader for the chip
2. Write in the correct fuse values to the chip
3. Test-flash a blinky-LED program to the chip via fastboot to make sure it's working

Finally, since the one-wire facility is so cool, but requires a bit of additional hardware to work, I've documented that too. Everything you'd need to get the thingy fabbed (or DIY) is in the hardware directory.

TL;DR

The build chain for fastboot went broken, and I "fixed" it by taking the build process in a different direction.

I've also included binaries, and a simple hardware project to support the one-wire feature with a FTDI USB/serial cable or equivalent.

The aim was to make it easy to use for everyone. See the project name.

If you have a chip that's not supported, either fork-and-pull-request or e-mail me. We'll get binaries up and running for you in no time.

Support Software

You'll need a fastboot-compatible uploader.

• For Linux: https://github.com/Boregard/FBoot-Linux
• For Mac (may not support one-wire): http://www.avrfreaks.net/index.php?module=Freaks%20Academy&func=viewItem&item_type=project&item_id=1927.
• For Windows: http://luani.de/projekte/updateloader/

Tutorial Example

Something about the timing with running the uploader and then tapping reset / powering chip on.

F(not-yet)AQ

1. Does AVRDUDE work with fastboot? Nope, you need an uploader.

2. I really need every pin on my ATtiny45. What can I do? Flash the bootloader set up for one-wire mode on the RESET pin, then disable the reset pin using the relevant fuse bits. Now instead of triggering a bootloader session by tapping reset, you do so by turning the chip on. Use the reset pin (PB5) normally in your code. Woot!

3. Will this work with my AVR-based Arduino? Sure, but unless you absolutely need one-wire mode you should probably stick with the Arduino-native Optiboot because fastboot won't work with the Arduino IDE, and that's a hassle. Optiboot is really pretty darn good.

4. Do you have any questions? I've got more answers.