Major Architecture Upgrade : OSD, Betaflight Rates & Build System Refactor

1. OSD, DMA + SYS

First off on the hardware side, I added native MSP-based OSD support for Walksnail video transmitters, built the SPI barometer driver for altitude tracking, and spun up a low-level health task that constantly monitors MPU registers and stack usage in the background. On top of that, I finally fixed the DMA stream conflicts (mainly in STMCubeMX) between TIM1 DShot motor outputs , ADC1, and SPI peripherals, so everything runs without collisions now.

2. SYS Health + Debugging

I also implemented a few other low level tasks, allowing me to monitor system health, based upon ram usage and storage used. This task prints out the amount at which each tasks stack is being used, allowing me to effectively debug whether a task was actually overflowing, vs an unrestricted read/write. Furthermore, the original canary values that I used, were completely replaced as they in fact were causing some of the “stack overflow” bugs (via unrestricted reads/write every 1 ms in SysTick_Handler).

3. Betaflight Rates + CLI Update

For flight feel, I implemented Betaflight’s Actual Rates algorithm with custom expo curves, so stick inputs map to target angular velocities with center-stick precision. I also completely separated serial communications by moving the interactive CLI to USART1 (accessible via nc -C localhost 1234 in terminal) and pushing system logs to USART3. Additionally, I removed the old telemetryTX task because its unauthorized reads/writes were completely breaking the RTOS scheduler, and expanded the CLI with a ton of commands for live sensor readings and more PID tuning. Speaking of which, I am planning to create a persistent file in /bin/, allowing for rates to be stored between runs, rather than being reset each during runtime, and having to be manually configured through the CLI.

4. Overhauled Building Workflow

Finally, I overhauled the whole developer workflow and build automation setup. The build.sh and build.bat scripts now auto-configure custom CMake profiles and generate a full disassembly file in /bin/ after every build for fast low-level debugging, while run.sh and run.bat automatically launch the right terminal windows on launch.

5. Future Additions:

I’m planning to build a closed-loop Renode simulation matrix to stream hardware data into every peripheral externally, letting me run 100% real production code during SIL testing! For this, I will utilize the currently blank simulate.py as well as certain commands in simulate.resc to create properly formatted dynamic buffers(which are not directly injected into the code), allowing me to properly test the DMA drivers, and many of the memory management helpers.