stm32定时器pwm驱动无源蜂鸣器

可以使用定时器的PWM输出来驱动无源蜂鸣器，具体实现方法可以参考以下代码：

#include "stm32f10x.h"

void TIM3_PWM_Init(void)
{
    GPIO_InitTypeDef GPIO_InitStructure;
    TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
    TIM_OCInitTypeDef TIM_OCInitStructure;

    RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE);
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);

    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(GPIOA, &GPIO_InitStructure);

    TIM_TimeBaseStructure.TIM_Period = 999;
    TIM_TimeBaseStructure.TIM_Prescaler = 71;
    TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1;
    TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
    TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure);

    TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
    TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
    TIM_OCInitStructure.TIM_Pulse = 500;
    TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;
    TIM_OC1Init(TIM3, &TIM_OCInitStructure);

    TIM_Cmd(TIM3, ENABLE);
}

int main(void)
{
    TIM3_PWM_Init();

    while(1)
    {
        // do something
    }
}

在上述代码中，我们使用了定时器3的PWM输出来驱动PA6引脚上的无源蜂鸣器。具体来说，我们设置了定时器的时钟分频、计数模式、周期和占空比，然后使能了定时器和输出比较通道1。在主函数中，我们可以执行其它任务，同时无源蜂鸣器会不断发出PWM信号，从而发出声音。