🛠 Industrial Automation: CAN FD Logging and PWM Control on XIAO STM32C5

Objectives

This advanced use case aims to design an industrial data acquisition system using the XIAO STM32C5 board. The goal is to read data from the LSM6DS3TR-C 6-axis inertial sensor, compensate for thermal drift via programmable PWM heating, and transmit this critical data over the CAN FD bus using the embedded TCAN3403-Q1 transceiver. This scenario illustrates the power of the 144 MHz Cortex-M33 core to manage multiple critical peripherals simultaneously.

Required Hardware

• Seeed Studio XIAO STM32C5 board (STM32C5A3CG)
• USB-C cable for power and debugging
• Logic analyzer or external CAN FD interface (for verification)
• STM32CubeIDE or Zephyr RTOS environment

Steps

1. Project Configuration: In STM32CubeIDE, create a new project for the STM32C5A3CG. Enable the 48 MHz external crystal to ensure optimal timing precision.
2. CAN FD Initialization: Configure the FDCAN2 peripheral. Select CAN FD mode with a data phase bitrate of 5 Mbit/s. The TCAN3403-Q1 transceiver is already wired with a 120 Ω termination resistor, requiring no additional hardware configuration for the bus.
3. LSM6DS3TR-C Management: Initialize the I2C or SPI interface (depending on the board schematic) to communicate with the LSM6DS3TR-C. Configure the control register to enable the accelerometer and gyroscope.
4. PWM Heating Implementation: The sensor has a heating circuit. Configure a PWM timer (e.g., TIM2) connected to the thermal control pin. In the main loop, adjust the duty cycle based on the internal temperature readout to maintain a stable temperature and reduce inertial measurement drift.
5. Data Transmission: Format CAN FD packets to include raw sensor data and heating status. Use the 1 MB internal flash memory to temporarily store data if the bus is saturated, leveraging the large storage capacity.

Verification

Connect the CAN FD analyzer to the CAN_H and CAN_L pins. Observe the transmitted frames. Verify that the data rate reaches 5 Mbit/s. On the serial monitor, confirm that the sensor temperature remains stable thanks to the PWM servo control, proving the efficiency of the thermal compensation.

Further Exploration

Explore using the 16 MB external flash for long-term CAN log storage. You can also use the second FDCAN1 controller by adding an external transceiver to create a gateway between two different CAN networks.