Dual DC Motor H-Bridge Firmware (STM32 BluePill)

Embedded C firmware designed and implemented by João Victor Pariz for the RoboIME autonomous robotics team to validate and control dual DC motor actuation through H-bridge power stages (L298N / discrete MOSFET bridges) using the STM32F103C8T6 (ARM Cortex-M3 / BluePill).

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🎯 System Architecture & Signal Flow

flowchart LR
    subgraph STM32F103C8T6 ["STM32F103C8T6 (BluePill 3.3V Logic)"]
        PA0["PA0 (M0_MAH)"]
        PA3["PA3 (M0_MBL)"]
        PA2["PA2 (M0_MBH)"]
        PA1["PA1 (M0_MAL)"]
        PC13["PC13 (Status LED)"]
    end

    subgraph HBridge ["H-Bridge Power Stage"]
        IN1["IN1 (M0_MBL)"]
        IN2["IN2 (M0_MBH)"]
        IN3["IN3 (M0_MAL)"]
        IN4["IN4 (M0_MAH)"]
    end

    subgraph Actuators ["RoboIME DC Motors"]
        MA[("DC Motor A")]
        MB[("DC Motor B")]
    end

    PA0 -->|Active Low| IN4
    PA3 -->|Active High| IN1
    PA2 -->|Active Low| IN2
    PA1 -->|Active High| IN3
    IN4 & IN1 --> MA
    IN2 & IN3 --> MB

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🎯 Overview & Objectives

• Generate synchronous quadrature switching pulses across STM32 GPIO outputs to validate directional rotation and commutation logic.
• Ensure dead-time separation between high-side and low-side switching to prevent shoot-through currents in power bridges.
• Provide visual status telemetry via the onboard active-low LED (PC13) to indicate loop execution and clock stability.

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🔌 Hardware Pinout & Wiring

Connect the STM32 BluePill GPIO pins to the H-bridge logic inputs according to the following layout:

STM32 Pin (BluePill)	H-Bridge Input	Function	Signal Logic
PA0	IN4 / M0_MAH	Motor B High-Side Drive	Active-Low / Inverted Logic
PA1	IN3 / M0_MAL	Motor B Low-Side Drive	Active-High Logic
PA2	IN2 / M0_MBH	Motor A High-Side Drive	Active-Low / Inverted Logic
PA3	IN1 / M0_MBL	Motor A Low-Side Drive	Active-High Logic
PC13	Onboard LED	Execution Status Indicator	Active-Low (0 = ON, 1 = OFF)
GND	GND	Common Reference Ground	Mandatory

⚠️ Grounding Precaution: Always ensure a shared common ground (GND) between the STM32 board and the motor power supply to avoid floating voltage references.

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🛠️ Project Structure

Teste-Ponte-H/
├── Core/
│   ├── Inc/
│   │   ├── main.h
│   │   ├── stm32f1xx_hal_conf.h
│   │   └── stm32f1xx_it.h
│   └── Src/
│       ├── main.c              # Application entry point & H-bridge control sequence
│       ├── stm32f1xx_hal_msp.c
│       ├── stm32f1xx_it.c      # Interrupt service routines
│       ├── syscalls.c
│       ├── sysmem.c
│       └── system_stm32f1xx.c  # CMSIS system initialization
├── Drivers/
│   ├── CMSIS/                  # ARM Cortex-M3 CMSIS headers
│   └── STM32F1xx_HAL_Driver/   # STMicroelectronics HAL drivers (GPIO, RCC, etc.)
├── testePonteH.ioc             # STM32CubeMX graphical configuration project
├── .gitignore
└── README.md

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⚡ Flashing & Debugging

1. Connect an ST-Link V2 programmer to the SWD header of the BluePill (SWDIO, SWCLK, 3.3V, GND).
2. Open STM32CubeProgrammer or your preferred toolchain (STM32CubeIDE, OpenOCD, or VS Code with Cortex-Debug).
3. Connect via SWD and flash the compiled binary.
4. Press the hardware Reset button to trigger the execution sequence.

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🔄 Execution Logic

The main application loop in main.c executes a periodic 4-phase sequence:

1. Turn ON Indicator: Asserts PC13 to visually signal motor activation.
2. Forward Rotation: Activates PA0 / PA3 for 2000 ms.
3. Braking & Hold: Deasserts drivers and turns OFF status LED for 1000 ms.
4. Reverse Rotation: Activates PA2 / PA1 for 2000 ms.
5. Full Stop: Safely deasserts all control lines for 1000 ms before repeating.

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👤 Author & Context

• João Victor Pariz (@VPariz) — Electronics Engineering undergraduate, Instituto Militar de Engenharia (IME).
• Developed within the context of the RoboIME Autonomous Systems team to validate hardware driver stages for mobile robotics.

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📜 License

This project is licensed under the MIT License.