Lập trình ngắt ngoài STM32

Đối với các trình xử lý ngắt, STM32F4 chỉ có 7 trình xử lý ngắt để xử lý ngắt ngoài từ line0 đến line15.

#include "stm32f4xx.h"
#include "stm32f4xx_rcc.h"
#include "stm32f4xx_gpio.h"
#include "stm32f4xx_exti.h"
#include "stm32f4xx_syscfg.h"
#include "misc.h"
#include "clock.h"
#include "delay.h"

void EXTI_Init(void)
{
    // Clock for GPIOA
    RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);
    // Clock for SYSCFG
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_SYSCFG, ENABLE);

    // GPIOA initialization as an input from user button (GPIOA0)
    GPIO_InitTypeDef GPIO_InitStruct;
    GPIO_InitStruct.GPIO_Mode = GPIO_Mode_IN;
    GPIO_InitStruct.GPIO_OType = GPIO_OType_PP;
    GPIO_InitStruct.GPIO_Pin = GPIO_Pin_0;
    GPIO_InitStruct.GPIO_PuPd = GPIO_PuPd_DOWN;
    GPIO_InitStruct.GPIO_Speed = GPIO_Speed_2MHz;
    GPIO_Init(GPIOA, &GPIO_InitStruct);

    // Selects the GPIOA pin 0 used as external interrupt source
    SYSCFG_EXTILineConfig(EXTI_PortSourceGPIOA, EXTI_PinSource0);

    // External interrupt settings
    EXTI_InitTypeDef EXTI_InitStruct;
    EXTI_InitStruct.EXTI_Line = EXTI_Line0;
    EXTI_InitStruct.EXTI_LineCmd = ENABLE;
    EXTI_InitStruct.EXTI_Mode = EXTI_Mode_Interrupt;
    EXTI_InitStruct.EXTI_Trigger = EXTI_Trigger_Rising;
    EXTI_Init(&EXTI_InitStruct);

    // Nested vectored interrupt settings
    NVIC_InitTypeDef NVIC_InitStruct;
    NVIC_InitStruct.NVIC_IRQChannel = EXTI0_IRQn;
    NVIC_InitStruct.NVIC_IRQChannelCmd = ENABLE;
    // EXTI0_IRQn has Most important interrupt
    NVIC_InitStruct.NVIC_IRQChannelPreemptionPriority = 0x00;
    NVIC_InitStruct.NVIC_IRQChannelSubPriority = 0x00;
    NVIC_Init(&NVIC_InitStruct);
}

void EXTI0_IRQHandler(void)
{
    // Checks whether the interrupt from EXTI0 or not
    if (EXTI_GetITStatus(EXTI_Line0))
    {
        // Toggle orange LED (GPIO13)
        GPIO_ToggleBits(GPIOD, GPIO_Pin_13);
        
        // Clears the EXTI line pending bit
        EXTI_ClearITPendingBit(EXTI_Line0);
    }
}

int main(void)
{
    // Set clock to 168MHz
    CLOCK_SetClockTo168MHz();

    // Delay initialization
    DELAY_Init();

    // External interrupt initialization
    EXTI_Init();

    // Clock for GPIOD
    RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOD, ENABLE);

    // GPIOD initialization as an output for orange LED (GPIOD13)
    // and blue LED (GPIOD15)
    GPIO_InitTypeDef GPIO_InitStruct;
    GPIO_InitStruct.GPIO_Mode = GPIO_Mode_OUT;
    GPIO_InitStruct.GPIO_OType = GPIO_OType_PP;
    GPIO_InitStruct.GPIO_Pin = GPIO_Pin_13 | GPIO_Pin_15;
    GPIO_InitStruct.GPIO_PuPd = GPIO_PuPd_NOPULL;
    GPIO_InitStruct.GPIO_Speed = GPIO_Speed_2MHz;
    GPIO_Init(GPIOD, &GPIO_InitStruct);

    while (1)
    {
        // Toggle blue LED (GPIO15)
        GPIO_ToggleBits(GPIOD, GPIO_Pin_15);
        // Delay 5s
        DELAY_Ms(5000);
    }
}