驱动无源蜂鸣器问题

lanpangzi · 发表于 2016-12-6 14:17:25

我自己写了程序  做了一个无源蜂鸣器的模块。想用PWM输出2KHz频率的方波来驱动，可是用万用表检测PWM输出端口没有输出信号。现在将程序贴过来，麻烦高手们帮小弟看一下！用的是战舰板的TIM3通道2 （PA7 IO口）
主函数
#include "timer.h"
int main(void)
{

TIM3_PWM_Init(36000,0);
TIM_SetCompare2(TIM3,50);

}

Timer函数
void TIM3_PWM_Init(u16 arr,u16 psc)
{
GPIO_InitTypeDef GPIO_InitStructure;
TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
TIM_OCInitTypeDef  TIM_OCInitStructure;

RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE);

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_7; //TIM_CH2
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(GPIOA, &GPIO_InitStructure);

TIM_TimeBaseStructure.TIM_Period = arr;
TIM_TimeBaseStructure.TIM_Prescaler =psc;
TIM_TimeBaseStructure.TIM_ClockDivision = 0;
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure);


TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM2;
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;
TIM_OC2Init(TIM3, &TIM_OCInitStructure);

TIM_OC2PreloadConfig(TIM3, TIM_OCPreload_Enable);

TIM_Cmd(TIM3, ENABLE);  //ê1ÄüTIM3

}