Arduino Nano 33 IoT Embedded Software Repository

This repository provides a setup for building, compiling, linking, and flashing source code to the Arduino Nano 33 IoT. The example main.cpp is a simple blinky with a little test string that is output on the Serial-to-USB interface of the Arduino.

Prerequisites

Ensure you have the following tools installed:

• ARM GNU Toolchain
• CMake >= 3.29
• GNU Make
• OpenOCD
• A suitable SWD programmer. I used the Raspberry Pi Debug Probe but any compatible SWD programmer will work.

Building

Clone the repository with submodules

git clone --recursive [email protected]:rubenstar/arduino_from_source.git

Build using cmake & make

mkdir build
cd build
cmake ..
make

Flashing

To flash the binary, use OpenOCD with your SWD programmer. The following command will flash the compiled main.elf:

openocd -f interface/cmsis-dap.cfg -f target/at91samdXX.cfg -c "program main.elf reset verify exit"

Supported Devices

This repository is currently tailored to the Arduino Nano 33 IoT which uses the SAMD21G18 chip. With a few minor changes you should be able to re-use this repo to support any Arduino though.

Important Notes

1. The example program you flash will be compiled without a bootloader. Compiling with the bootloader is currently not supported.
2. If you need to restore the original bootloader, you can do so with the following command from the top-level directory:

   openocd -f interface/cmsis-dap.cfg -f target/at91samdXX.cfg -c "program lib/arduino_core/ArduinoCore-samd/bootloaders/nano_33_iot/samd21_sam_ba_arduino_nano_33_iot.bin verify exit 0x00000000"

3. I am using a custom linker script located at lib/build_files/samd21g18a.ld. It's more minimalistic than the ones that come with ArduinoCore-samd, and has some explanatory comments. You should be able to use linker scripts from the official repository too though, as long as they don't include the bootloader.