The external interrupt/event controller (External Interrupt/Event Controller, EXTI) of the STM32 microcontroller manages the interrupt/event line of the controller. Each interrupt/event line corresponds to an edge detector, which can detect the rising edge and falling edge of the input signal. EXTI can realize the individual configuration of each interrupt/event line, which can be individually configured as an interrupt or event, and the attributes of the trigger event.
One, add interrupt service routine
void EXTI0_IRQHandler(void)
{
if(EXTI_GetITStatus(EXTI_Line0) != RESET)
{
// Toggle LED
GPIOB->ODR ^= GPIO_Pin_All;
// Clear the EXTI line 0 pending bit
EXTI_ClearITPendingBit(EXTI_Line0);
}
}
Two, configure EXTI
void EXTI0_Config(void)
{
EXTI_InitTypeDef EXTI_InitStructure;
GPIO_InitTypeDef GPIO_InitStructure;
NVIC_InitTypeDef NVIC_InitStructure;
// Enable GPIOC clock
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOC, ENABLE);
// Configure PC.00 pin as input floating
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
GPIO_Init(GPIOC, &GPIO_InitStructure);
// Enable AFIO clock
RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO, ENABLE);
// Connect EXTI0 Line to PC.00 pin
GPIO_EXTILineConfig(GPIO_PortSourceGPIOC, GPIO_PinSource0);
// Configure EXTI0 line
EXTI_InitStructure.EXTI_Line = EXTI_Line0;
EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;
EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Falling;
EXTI_InitStructure.EXTI_LineCmd = ENABLE;
EXTI_Init(&EXTI_InitStructure);
// Enable and set EXTI0 Interrupt to the lowest priority
NVIC_InitStructure.NVIC_IRQChannel = EXTI0_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0x0F;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0x0F;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);
}