Bismuth-Project

Bismuth-Project is an embedded systems portfolio project demonstrating real-time communication between an STM32 microcontroller and a Raspberry Pi Pico over the CAN bus.

The STM32 acts as the main controller, running FreeRTOS to manage multiple tasks for communication and data handling. The Raspberry Pi Pico functions as a peripheral, reading sensor data and transmitting it via CAN.

🛠️ Technologies

• STM32
• Raspberry Pi Pico
• CAN Bus Communication
• FreeRTOS
• Arduino
• C / C++

🚀 Goals

• Implement multi-tasking with FreeRTOS on STM32
• Communicate via CAN between STM32 and Pico
• Read and transmit real sensor data
• Serve as a clean, modular, and well-documented portfolio project

📟 Required Hardware

• STM32F4DISCOVERY
• Raspberry Pi Pico YD-RP2040
• CAN transceiver: TJ1050 and MCP2515
• Ultrasonic Sensor HC SR04

📐 System Architecture

STM Implementation

This diagram illustrates the architecture of the STM32 FreeRTOS-based application in the Bismuth-Project, specifically how tasks interact with the CAN bus:

• Task 1 and Task 2 represent FreeRTOS tasks responsible for different system functionalities—e.g., processing sensor data, monitoring communication, or triggering events.

• Both tasks interface with a CAN Manager module, which centralizes CAN communication. This abstraction ensures that message sending, receiving, filtering, and buffering are handled in a consistent and synchronized way.

• The CAN Manager interacts with the Hardware Abstraction Layer (HAL) to perform low-level communication with the CAN peripheral on the STM32.

block-beta
 columns 2
 t1["Task 1"] t2["Task 2"] 
 space:2
 man["CAN Manager"]:2
 space:2
 hal["Hardware Abstraction Layer"]:2
 
 t1 --> man
 t2 --> man
 man --> hal

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In this demonstration, Task 1 is responsible for requesting a specific frame from the Pico, interpreting the ultrasonic sensor data and turning on an LED based on the measured distance.

Task 2 is responsible for receiving a specific frame when the USR button on the Pico board is pressed, toggling the red LED on the ST's board and halting Task 1.

Pico Implementation

flowchart TD
        A(["Start"])
        A --> E{"USR button pressed?"}
        E --> |No| B["Read CAN frame"]
        B --> C{"Remote Transmission Request?"}
        C -->|Yes| D["Read distance"]

        E --> |Yes| G["Send CAN frame with ID 0x103"]
        

        D --> F["Return distance value over CAN"]

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