stm32如何使用外部中断调整pwm占空比

在STM32中，可以使用外部中断来触发定时器的更新事件，从而实现PWM的占空比调整。具体步骤如下：

1. 初始化外部中断，使其可以触发定时器的更新事件。
2. 初始化定时器，设置PWM的周期和初始占空比。
3. 在定时器中断处理函数中，根据外部中断的触发来更新PWM的占空比。

下面是一个简单的示例代码：

#include "stm32f10x.h"

void EXTI0_IRQHandler(void) // 外部中断处理函数
{
    TIM_OCInitTypeDef TIM_OCInitStructure;
    if (EXTI_GetITStatus(EXTI_Line0) != RESET) {
        TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
        TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
        TIM_OCInitStructure.TIM_Pulse = 1000; // 占空比为50%
        TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;
        TIM_OC1Init(TIM1, &TIM_OCInitStructure);
        EXTI_ClearITPendingBit(EXTI_Line0);
    }
}

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

    // 使能外部中断所在的GPIO和外部中断线
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_AFIO, ENABLE);
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU;
    GPIO_Init(GPIOA, &GPIO_InitStructure);
    GPIO_EXTILineConfig(GPIO_PortSourceGPIOA, GPIO_PinSource0);
    EXTI_InitTypeDef EXTI_InitStructure;
    EXTI_InitStructure.EXTI_Line = EXTI_Line0;
    EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;
    EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Rising;
    EXTI_InitStructure.EXTI_LineCmd = ENABLE;
    EXTI_Init(&EXTI_InitStructure);

    // 使能定时器时钟
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM1, ENABLE);

    // 配置定时器为PWM输出模式
    TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
    TIM_TimeBaseStructure.TIM_Period = 2000 - 1; // PWM周期为2ms
    TIM_TimeBaseStructure.TIM_Prescaler = 72 - 1; // 定时器分频系数为72
    TIM_TimeBaseStructure.TIM_ClockDivision = 0;
    TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
    TIM_TimeBaseInit(TIM1, &TIM_TimeBaseStructure);
    TIM_Cmd(TIM1, ENABLE);

    // 配置定时器的PWM通道
    TIM_OCInitTypeDef TIM_OCInitStructure;
    TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
    TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
    TIM_OCInitStructure.TIM_Pulse = 1000; // 初始占空比为50%
    TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;
    TIM_OC1Init(TIM1, &TIM_OCInitStructure);

    // 配置外部中断的中断向量
    NVIC_InitStructure.NVIC_IRQChannel = EXTI0_IRQn;
    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
    NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
    NVIC_Init(&NVIC_InitStructure);

    while (1) {
        // 主循环中可以执行其他任务
    }
}

相关问题:
1. 怎样通过stm32控制pwm输出？
2. 外部中断有哪些触发方式？
3. stm32的定时器有哪些工作模式？