LED Fade STM32 HC-05 Bluetooth Module

Prerequisites

This project assumes you have already installed STM32CubeIDE. You need to have previously done a basic blink sketch with blue-pill using STM32CubeIDE. I have made a complete video from installing STM32CubeIDE to LED blink program. You can watch it by clicking this link. https://www.youtube.com/watch?v=kXg467nVd_A

Wiring Diagram

STM32CubeIDE Settings

Enable USART1 asynchronous

Parameter Settings --> Basic Parameters --> Baud rate 9600

NVIC Settings --> USART1 global interrupt --> (Tick)

Click Timer → Click TIM2 →

Clock Source set to Internal Clock

Channel2 set to PWM Generation CH2

Configuration → Parameter Settings →

Prescaler set to 127

Counter Period 625

Additional code on top of STM32CubeIDE generated code

/* USER CODE BEGIN PV */
uint8_t rx_data;
int pwm = 0;
/* USER CODE END PV */

  /* USER CODE BEGIN 2 */
  HAL_TIM_PWM_Start(&htim2, TIM_CHANNEL_2);
  HAL_UART_Receive_IT(&huart1,&rx_data,1);
  // receive data (one character only)
  /* USER CODE END 2 */

/* USER CODE BEGIN 4 */
void HAL_UART_RxCpltCallback(UART_HandleTypeDef *huart)
{
  if(huart->Instance==USART1)
  {
    if(rx_data == 82) //if "R" reset
    {
      pwm = 0;
    }
    else  if(rx_data == 65) // if  "A" set pwm
    {
      __HAL_TIM_SET_COMPARE(&htim2,TIM_CHANNEL_2, pwm * 2);
    }
    else  if(rx_data > 47 && rx_data < 58) // if "0" - "9" construct
    {
      pwm = pwm * 10 + rx_data - 48;
    }
    // Enabling interrupt receive again (one character only)
    HAL_UART_Receive_IT(&huart1,&rx_data,1);
  }
}
/* USER CODE END 4 */

Wiring Diagram for 12V