solo/docs/building.md

To build, develop and debug the firmware for the STM32L442 (WIP!) via cross-compilation on Linux, no vendor-specific software is necessary.

There exists a development board NUCLEO-L432KC you can use; the L432 chip differs from the L442 used for Solo only in that it lacks a cryptographic accelerator. The board does contain a debugger, so all you need is a USB cable (and some udev rules).

You will need the following packages (naming given for Arch Linux):

• arm-none-eabi-gcc
• arm-none-eabi-newlib
• arm-none-eabi-binutils

and one of

• openocd
• stlink

If you remove the .exe extensions in the Makefile, and possibly add a -g flag, compilation runs through.

To flash and step through the code:

• connect the Nucleo to your PC
• attach one of the debuggers: st-util (for stlink), or openocd -f interface/stlink-v2-1.cfg -f target/stm32l4x.cfg (for openocd)
• launch gdb via arm-none-eabi-gdb -q solo.elf
• connect gdb to the debugger via target extended-remote :4242 (for stlink), or target remote :3333 (for openocd)
• flash the firmware via load
• optionally set a breakpoint via break main
• continue, and start stepping 🙌

Note that the code for targets/stm32l442 currently consists of only a blinky hello world...