IAR FOR ARM编程,外部中断下降沿触发按键导致LED1亮灭

以下是IAR FOR ARM编程的代码，实现外部中断下降沿触发按键导致LED1亮灭：

#include "stm32f10x.h"

void Delay(uint32_t nCount);

int main(void)
{
    GPIO_InitTypeDef GPIO_InitStructure;
    EXTI_InitTypeDef EXTI_InitStructure;
    NVIC_InitTypeDef NVIC_InitStructure;

    /* Enable GPIOB clock */
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE);

    /* Configure PB12 as input floating */
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_12;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
    GPIO_Init(GPIOB, &GPIO_InitStructure);

    /* Enable AFIO clock */
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO, ENABLE);

    /* Connect EXTI Line12 to PB12 pin */
    GPIO_EXTILineConfig(GPIO_PortSourceGPIOB, GPIO_PinSource12);

    /* Configure EXTI Line12 to generate an interrupt on falling edge */
    EXTI_InitStructure.EXTI_Line = EXTI_Line12;
    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 EXTI Line12 Interrupt to the lowest priority */
    NVIC_InitStructure.NVIC_IRQChannel = EXTI15_10_IRQn;
    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0x0F;
    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0x0F;
    NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
    NVIC_Init(&NVIC_InitStructure);

    /* Enable GPIOC clock */
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOC, ENABLE);

    /* Configure PC13 as output push-pull */
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_13;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(GPIOC, &GPIO_InitStructure);

    while (1)
    {
        /* Do nothing */
    }
}

void EXTI15_10_IRQHandler(void)
{
    /* Clear the EXTI line 12 pending bit */
    EXTI_ClearITPendingBit(EXTI_Line12);

    /* Toggle PC13 */
    GPIO_WriteBit(GPIOC, GPIO_Pin_13, (BitAction)(1 - GPIO_ReadOutputDataBit(GPIOC, GPIO_Pin_13)));

    /* Delay */
    Delay(0xFFFFF);
}

void Delay(uint32_t nCount)
{
    uint32_t i;
    for (i = 0; i < nCount; i++)
    {
    }
}

在这个例程中，我们首先启用了GPIOB和GPIOC的时钟，并将PB12配置为输入浮动，并将PC13配置为输出推挽。然后，我们启用了AFIO时钟，并将EXTI线12连接到PB12引脚。接下来，我们配置了EXTI线12以在下降沿触发时生成中断，并将中断优先级设置为最低。最后，我们在while循环中等待中断的发生。

在EXTI15_10_IRQHandler中，我们首先清除了EXTI线12的挂起位，然后切换PC13的状态，并进行延迟。这样，当我们按下PB12时，PC13会亮起，当我们放开PB12时，PC13会熄灭。