This project contains a simple uart based bootloader which can be used as a starting point for further experiments or dropped into production right away.

The bootloader is designed to allow easy in-system updates for SAMD10C/D MCUs.

Using this bootloader is simple:

• Create your firmware, link it with the bootloader-variant of the linker script. (can be found here)
• Upload the bootloader to your device using SWD.
• When the bootloader detects that no firmware is programmed, it will wait for a firmware to be uploaded.
• Upload your firmware using the upload.py tool.

Note that your user-firmware has to include a function to enter the bootloader, one is provided here

Hints:

• The bootloader requires 16 bytes of memory at the beginning of the memory address space.
• If you write a specific value (0xDEADBEEF) to the first 16 bytes and issue an NVIC_SystemReset(), the bootloader will wait for a new firmware to be uploaded.
• Currently, there is no timeout implemented, which means if you are within the bootloader it won't exit automatically.
• upload.py has lots of options, especially a strict verification you won't overwrite your bootloader.
• You are able to use interrupts in your user firmware, as the bootloader will relocate the interrupt vector table accordingly.

The source code can be found in main.c, it is based on the awesome mcu-starter-projects by Alex Taradov.

You can compile the project without any IDE installed, you will need arm-none-eabi-gcc and make. If you have anything in place, just type make and you're done.

The provided binaries are built with GCC 7.3, however older versions should be fine.