I write embedded C for STM32 and ESP32 chips, either bare metal or with FreeRTOS, depending on the job. If your board starts losing RS485 frames or freezing up when CAN traffic gets heavy, I always go straight to the interrupt handlers and DMA buffers. I’ve put together drivers with 2KB ring buffers before, so the firmware keeps going even when there’s a lot of industrial noise.
I also handle Nordic BLE and ESP32 Wi-Fi if wireless comes into play.
Got a schematic or MCU datasheet? Send it over—I’ll take a look. Let’s see what you’re building.