STM32 H-Bridge DC Motor Control: PWM & Direction Management

Project Description

This project demonstrates how to implement an H-Bridge DC motor control system using an STM32F103C6 microcontroller. The system provides bidirectional control of a DC motor through GPIO pins for direction and PWM for speed regulation. By manipulating the H-Bridge configuration, the motor can rotate in both clockwise and counterclockwise directions, while PWM techniques enable precise speed control. Real-time status feedback is provided via UART, and a full Proteus simulation validates the complete motor control system.

The H-Bridge circuit, typically implemented with an IC like the L298N, uses a transistor configuration that forms an "H" pattern, allowing current to flow through the motor in both directions by controlling the saturation states of different transistor pairs.

STM32CubeMX Setup

• MCU Selection: STM32F103C6 (72 MHz clock)
• GPIO Configuration:

-PA4, PA5 configured as Output Push-Pull (Motor direction control pins IN1, IN2)

• TIM2 Configuration:

• -Channel 1 (PA0) configured as PWM Generation
• -Prescaler: 72-1 (1 MHz timer clock)
• -Counter Period: 999 (1 kHz PWM frequency)
• -Pulse: 0 (initial duty cycle)

• UART1 Configuration:

• -Baud Rate: 115200
• -Word Length: 8 bits
• -Parity: None
• -Stop Bits: 1

• Generate initialization code in STM32CubeIDE.

STM32CubeIDE Setup

Key Functions

• Button Debouncing & State Handling

• -void HandleStartStop(void);
• -Manages the start/stop button with debouncing, toggles motor state, and sends UART status messages.
• -void HandleDutyCycle(void);
• -Handles duty cycle button press with debouncing and cycles through speed settings (25%, 50%, 75%, 99%).

• PWM Control & Motor Management

• -void UpdatePWM(void);
• -Updates PWM duty cycle based on current setting, calculates angular acceleration, and sends UART updates with motor status.

• UART Communication

• -void SendUartMessage(char* message);
• -Transmits status and debugging messages via UART to a serial terminal.

• Main Loop Logic

while (1)
{
HandleStartStop();    // Check start/stop button
HandleDutyCycle();    // Check speed change button
}

Proteus Simulation

Required Components:

• STM32F103C6 microcontroller
• H-Bridge Motor Driver
• DC Motor
• Virtual Terminal (UART)

Connections:

• Direction Control: PA4 → L298N IN1, PA5 → L298N IN2
• Speed Control: PA0 → L298N ENA (PWM input)
• Motor Connections: L298N outputs → DC Motor terminals
• UART1: PA9 (TX) → Virtual Terminal RX
• Power: L298N VSS → 5V, VS → Motor voltage (e.g., 12V)

Steps:

• Load the.hex file compiled from CubeIDE.
• Run the simulation.
• Observe motor direction changes and speed variations.
• Monitor the real-time status updates on the Virtual Terminal showing direction and PWM duty cycle.

That's all!

If you have any questions or suggestions don't hesitate to leave a comment below