GPIO_EXTI Example Description

How to configure external interrupt lines.

In this example, one EXTI line (EXTI_Line8) is configured to generate an interrupt on each falling edge. In the interrupt routine a led connected to a specific GPIO pin is toggled.

In this example:

  • EXTI_Line8 is connected to PA.08 pin
  • when falling edge is detected on EXTI_Line8, LED3 toggles once

On STM32C0116-DISCO:

  • EXTI_Line8 is connected to Joystick Selection push-button

In this example, HCLK is configured at 48 MHz.

Notes

  1. Care must be taken when using HAL_Delay(), this function provides accurate delay (in milliseconds) based on variable incremented in SysTick ISR. This implies that if HAL_Delay() is called from a peripheral ISR process, then the SysTick interrupt must have higher priority (numerically lower) than the peripheral interrupt. Otherwise the caller ISR process will be blocked. To change the SysTick interrupt priority you have to use HAL_NVIC_SetPriority() function.

  2. The example needs to ensure that the SysTick time base is always set to 1 millisecond to have correct HAL operation.

Keywords

System, GPIO, EXTI, Output, Alternate function, Push-pull, Toggle

Directory contents

  • GPIO/GPIO_EXTI/Inc/stm32c0xx_hal_conf.h HAL configuration file
  • GPIO/GPIO_EXTI/Inc/stm32c0xx_it.h Interrupt handlers header file
  • GPIO/GPIO_EXTI/Inc/main.h Header for main.c module
  • GPIO/GPIO_EXTI/Src/stm32c0xx_it.c Interrupt handlers
  • GPIO/GPIO_EXTI/Src/stm32c0xx_hal_msp.c HAL MSP file
  • GPIO/GPIO_EXTI/Src/main.c Main program
  • GPIO/GPIO_EXTI/Src/system_stm32c0xx.c STM32C0xx system source file

Hardware and Software environment

  • This example runs on STM32C011F6Ux devices.

  • This example has been tested with STM32C0116-DISCO board and can be easily tailored to any other supported device and development board.

How to use it ?

In order to make the program work, you must do the following :

  • Open your preferred toolchain
  • Rebuild all files and load your image into target memory
  • Run the example