STM32 Basics

Implementation of basic components such as a timer, LCD display, external interrupt, and digital pins on the STM32 microcontroller. The microcontroller used is the STM32F103R6 model, operating at a clock frequency of 44MHz.

Digital Pin

Two green and red LEDs are connected to digital pins in the microcontroller. We want to turn them on and off periodically.

The important part of the code corresponding to this component is in the main.c while loop as below:

  while (1)
  {
	  HAL_GPIO_WritePin(X1_GPIO_Port,X1_Pin,GPIO_PIN_SET);
	  HAL_Delay(500);
	  HAL_GPIO_WritePin(X1_GPIO_Port,X1_Pin,GPIO_PIN_RESET);
	  HAL_Delay(500);
    /* USER CODE END WHILE */

    /* USER CODE BEGIN 3 */
  }

Digital Pin Digital Input

Two push buttons with pull-up resistors connected to them as their output are connected to a STM32 microcontroller. The goal is to turn the LED's on and off by pushing those buttons.

The important part of the code corresponding to this component is in the main.c while loop as below:

  while (1)
  {
	  if(HAL_GPIO_ReadPin(Y2_GPIO_Port,Y2_Pin)==0){
		  HAL_GPIO_WritePin(X2_GPIO_Port,X2_Pin,GPIO_PIN_SET);
		  HAL_GPIO_WritePin(X1_GPIO_Port,X1_Pin,GPIO_PIN_RESET);
	  }
	  if(HAL_GPIO_ReadPin(Y1_GPIO_Port,Y1_Pin)==0){
		  HAL_GPIO_WritePin(X2_GPIO_Port,X2_Pin,GPIO_PIN_RESET);
		  HAL_GPIO_WritePin(X1_GPIO_Port,X1_Pin,GPIO_PIN_SET);
	  }
    /* USER CODE END WHILE */

    /* USER CODE BEGIN 3 */
  }

External Interrupt

Two pins are defined on the microcontroller. We have a pushup button and a digital input connected to them. The goal is to have the LED's blink in a certain speed when pushing the buttons.

The important part of the code corresponding to this component is in the main.c while loop as below:

  while (1)
  {
	  if (condition == 0){
	  	  HAL_GPIO_WritePin(X1_GPIO_Port,X1_Pin,GPIO_PIN_SET);
	  	  HAL_GPIO_WritePin(X2_GPIO_Port,X2_Pin,GPIO_PIN_SET);
	  }
	  if (condition == 1){
		  HAL_GPIO_WritePin(X1_GPIO_Port,X1_Pin,GPIO_PIN_RESET);
		  HAL_GPIO_TogglePin(X2_GPIO_Port, X2_Pin);
		  		  HAL_Delay(100);
	  }
	  if(HAL_GPIO_ReadPin(Y1_GPIO_Port,Y1_Pin)==1){
	  	  HAL_GPIO_WritePin(X1_GPIO_Port,X1_Pin,GPIO_PIN_SET);
	  	  HAL_GPIO_WritePin(X2_GPIO_Port,X2_Pin,GPIO_PIN_SET);
		  condition = 0;
	  }
    /* USER CODE END WHILE */

    /* USER CODE BEGIN 3 */
  }

void HAL_GPIO_EXTI_Callback ( uint16_t GPIO_Pin)
	{
	if(GPIO_Pin == Y2_Pin)
		condition = 1;
	else if(GPIO_Pin == Y1_Pin)
		condition = 0;
	}

LCD Display

Part A

Connected an LCD to the STM32 microcontroller, and printed my name and student number in its first two lines. The ports and pins corresponding to the LCD are as follows:

  Lcd_PortType ports [] = {
  		D4_GPIO_Port, D5_GPIO_Port, D6_GPIO_Port, D7_GPIO_Port
  };
  Lcd_PinType pins [] = {
  		D4_Pin, D5_Pin, D6_Pin, D7_Pin
  };

  Lcd_HandleTypeDef lcd = Lcd_create(ports, pins, RS_GPIO_Port, RS_Pin, E_GPIO_Port, E_Pin, LCD_4_BIT_MODE);

  while (1)
  {
	  Lcd_cursor(&lcd, 0,0);
	  Lcd_string(&lcd, "Fardin");

	  Lcd_cursor(&lcd, 1,0);
	  Lcd_string(&lcd, "810199456");
    /* USER CODE END WHILE */

    /* USER CODE BEGIN 3 */
  }
  /* USER CODE END 3 */
}

Part B

The last three digits of my student number will be stored in a variable called 'a', and 'a' will be divided by 7 and stored in a variable named 'b'. On the first line, 'a' will be displayed, and on the second line, 'b' will be shown with four decimal places.

  Lcd_PortType ports [] = {
  		D4_GPIO_Port, D5_GPIO_Port, D6_GPIO_Port, D7_GPIO_Port
  };
  Lcd_PinType pins [] = {
  		D4_Pin, D5_Pin, D6_Pin, D7_Pin
  };

  Lcd_HandleTypeDef lcd = Lcd_create(ports, pins, RS_GPIO_Port, RS_Pin, E_GPIO_Port, E_Pin, LCD_4_BIT_MODE);

  int StNumber = 456;
  float FloatNumber = (float)StNumber/7;
  char String [50];
  while (1)
  {
	  sprintf(String, (char*)"%d" , StNumber);
	  Lcd_cursor(&lcd, 0,0);
	  Lcd_string(&lcd, String);
	  sprintf(String, (char*)"%.4f" , FloatNumber);
	  Lcd_cursor(&lcd, 1,0);
	  Lcd_string(&lcd, String);
    /* USER CODE END WHILE */

    /* USER CODE BEGIN 3 */
  }
  /* USER CODE END 3 */
}

Timer

Connected a timer to our STM32 micro controller that resets after some time to an initial value. The code corresponding to this component is in the main.c while loop as below:

  Lcd_PortType ports [] = {
   		D4_GPIO_Port, D5_GPIO_Port, D6_GPIO_Port, D7_GPIO_Port
   };
  Lcd_PinType pins [] = {
   		D4_Pin, D5_Pin, D6_Pin, D7_Pin
   };

  Lcd_HandleTypeDef lcd = Lcd_create(ports, pins, RS_GPIO_Port, RS_Pin, E_GPIO_Port, E_Pin, LCD_4_BIT_MODE);

  int a = 0;
  while (1)
  {
    /* USER CODE END WHILE */
	  while (a<51){
		  Lcd_cursor(&lcd, 0, 0);
		  Lcd_int(&lcd, a);
		  HAL_Delay(50);
		  Lcd_clear(&lcd);
		  a++;
	  }
	  if (a == 51){
		  a = 0;
	  }
    /* USER CODE BEGIN 3 */
  }
  /* USER CODE END 3 */
}