STM32 GPIO

What is GPIO ?

GPIO is short-form for General Purpose Input/Output pins, and these are used to control digital signals (high and low signals).

• GPIO can be configured as output, input or input with external interrupt

• In most cases, GPIO pins can have 1 of 3 pull up/down configurations:

  1. no pull-up and no pull-down
  2. pull-up
  3. pull-down
  • For example, pull-up means that when the pin is shorted to ground, the MCU will detect that as an input signal

.ioc Configuration

1. Configure GPIO pins

Code

1. GPIO state variable declaration

   /* USER CODE BEGIN 0 */
   
   GPIO_PinState pin_state;
   
   /* USER CODE END 0 */
   

2. GPIO output

   /* USER CODE BEGIN 3 */
   
   // Set Pin A0 high. This can be used to turn on an LED or activate any other device connected to Pin A0.
   HAL_GPIO_WritePin(GPIOA, GPIO_PIN_0, GPIO_PIN_SET);
   
   // Delay for some time. This allows you to see the effect of turning the Pin high for a specific duration.
   HAL_Delay(1000); // Delay for 1 second.
   
   // Set Pin A0 low. This can be used to turn off an LED or any other devices connected to Pin A0.
   HAL_GPIO_WritePin(GPIOA, GPIO_PIN_0, GPIO_PIN_RESET);
   
   /* USER CODE END 3 */
   

3. GPIO input

   /* USER CODE BEGIN 4 */
   
   // Read input from Pin B0.
   pin_state = HAL_GPIO_ReadPin(GPIOB, GPIO_PIN_0);
   
   // Check the state of the pin and do something based on the state.
   if (pin_state == GPIO_PIN_SET) {
   // If Pin B0 is high, then whatever the code inside the if statement will execute. 
   } else {
   // If Pin B0 is low, then whatever the code inside the else statement will execute.
   }
   
   /* USER CODE END 4 */