The Wombat robot uses a two-processor architecture. A Raspberry Pi handles high-level logic, vision, networking, and user code. An STM32F427 microcontroller handles everything that requires hard real-time guarantees: motor PWM generation, back-EMF sampling, closed-loop motor control, sensor ADC scanning, and IMU data acquisition. This split is not optional — the Linux scheduler on the Pi cannot provide the microsecond-level timing that back-EMF based position tracking requires.

This section documents the firmware running on the STM32 and the full data pipeline connecting it to user Python code.

Sections

• Architecture Overview — what each processor does and why
• SPI Communication Protocol — the shared-memory duplex buffers between Pi and STM32
• Motor Control — PWM generation, back-EMF measurement, PID loops, operating modes
• Sensor Reading — analog ports, digital ports, battery voltage, IMU
• Data Pipeline — the full path from physical signal to Python API
• Build and Flash — how to compile and program the firmware

Source Repositories