Firmware Build Instructions

Windows

For some reason that I can't figure out, builds on Windows seem to generate a smaller firmware binary than when built on Ubuntu with the same version of arm-none-eabi-gcc. Hydra firmware is pushing to be about 90% of available flash memory! This means, I recommend you to use Windows to build this firmware. (I am open to changing this recommendation once I have an explanation and solution to make Linux builds smaller)

Installing ARM Toolchain

Download installer from https://developer.arm.com/downloads/-/gnu-rm

Install it to the path C:\ProgramFiles\GNUArmEmbeddedToolchain\10.2021.10 (the version might be different), check the checkbox "Add path to environmental variable"

(if it is not added to the system PATH, then add C:\ProgramFiles\GNUArmEmbeddedToolchain\10.2021.10\bin to your system PATH manually)

Installing Make

If you don't already have a copy of make, then the minimal way to get it is to download it from https://packages.msys2.org/package/make where it says File: https://mirror.msys2.org/msys/x86_64/make-4.4.1-1-x86_64.pkg.tar.zst, the version numbers might be different.

Extract it, rename the usr directory to msys-make, and place it in C:\ProgramFiles\msys-make, and add C:\ProgramFiles\msys-make\bin to your system PATH

Ubuntu (or Ubuntu for Windows)

Make sure you have the tools installed with sudo apt-get install build-essentials gcc-arm-embedded

Running a Build

Open a new terminal or command line prompt. (a new instance makes sure that the latest changes to PATH is effective)

Use cd to navigate to the code repository.

Use the command make clean first. Then use the command make, which should generate all of the firmware files.

For a single target, the command looks like make -s MCU_TYPE=<MCU> TARGET=<TARGETNAME> binary , for example, make -s MCU_TYPE=F051 TARGET=REPEAT_DRIVE_F051 binary

Batch build will be slow as all the files need to be completely rebuilt for every ESC target. Individual targets can be rebuilt quickly without starting from a clean state.

Modifying a Build

Compiler preprocessor defines that can be enabled or disabled to save memory:

• ENABLE_LED_BLINK complex blinking behavior vs simple colours and simple blinks
• ENABLE_COMPILE_CLI if the CLI is available, a ton of memory is used for printf. Disable this if the firmware needs to be locked-down

I have fanagled around with a bunch of build options to minimize the final flash size. Also, I have removed all instances of malloc and new.

The targets named STM32F051DISCO or STM32G071NUCLEO are meant for the official ST development boards with built-in debuggers. The firmware will instantiate a dedicated UART for debugging-printf and CLI. The AM32 bootloader is not required for the development boards as the linker script has a different flash starting address.

Helpful debugging constants:

• DEBUG_PRINT will activate dbg_printf statements throughout the code
• DEBUG_EVENTCNT will activate code that tracks how many times a particular event has occured. Get these counts using uint32_t dbg_evntcnt_get(uint8_t id) where id is one of the DBGEVNTID_ enum items. See debug_tools.h for a list
• DEBUG_PINTOGGLE will cause some pins to change state on certain events, useful for debugging timing using a logic analyzer attached to those pins.
• SIMULATE_* will allow a 3rd CRSF input channel to inject sensor data for simulation. For example, to simulate over-current situations, use SIMULATE_CURRENT_LIMIT, the input channel 3 will override the data from the current sensor ADC.

Using IDE

There is a .cproject file available to build the development board firmwares, this can be opened with STM32CubeIDE. This is useful for using the ST-Link debugger to debug the code. It is not meant for building actual ESC firmware.

There are some *.launch_ files available inside the src-mcu directory. Rename these to *.launch and then they can be imported into STM32CubeIDE as debugger configurations. These configurations are likely out-of-date because the file name of the *.elf file inside will change as the project version is changing.