第八个实验 PWM控制蜂鸣器

配置PWM时应遵循以下步骤
1）将相应的GPIO管脚设为PWM模式
2）设置PWM模块时钟分频数
3）给PWM提供时钟
4）调用PWMGenConfigure配置PWM
5）调用PWMGenPeriodSet和PWMPulseWidthSet设置周期和脉宽
6）调用PWMOutputState使能PWM输出管脚
7）调用PWMGenEnable使能PWM模块

#include "stm32f10x.h"
int main()
{
 GPIO_InitTypeDef         GPIO_InitStructure;
 TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
 TIM_OCInitTypeDef        TIM_OCInitStructure;

//使能TIM2时钟

 RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2,ENABLE); 

//使能GPIOA和复用功能时钟
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);

设置GPIO模式
 GPIO_InitStructure.GPIO_Pin = GPIO_Pin_1; //TIM2¶þͨµÀPWM²¨ÐÎÊä³ö¶Ë¿ÚPA1
 GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;//¸´ÓÃÍÆÍìÊä³ö
 GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;//50MHz
 GPIO_Init(GPIOA, &GPIO_InitStructure);

//设置分频器基本单位结构体
 TIM_TimeBaseStructure.TIM_Period = 3600-1;//×Ô¶¯ÖØ×°ÔØÖµ£¬È¡Öµ±ØÐëÔÚ0x0000~0xFFFFÖ®¼ä
 TIM_TimeBaseStructure.TIM_Prescaler =10-1;//Ô¤·ÖƵֵ£¬+1Ϊ·ÖƵϵÊý£¬È¡Öµ±ØÐëÔÚ0x0000~0xFFFFÖ®¼ä       
 TIM_TimeBaseStructure.TIM_ClockDivision = 0;     //ʱÖÓ·Ö¸î
 TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up; //ÏòÉϼÆÊýģʽ 
 TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure);

//设置基本单位结构体

 TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;             //TIMÂö³å¿í¶Èµ÷ÖÆģʽ1
 TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable; //±È½ÏÊä³öʹÄÜ
 TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;     //Êä³ö¼«ÐÔ:
 TIM_OCInitStructure.TIM_Pulse=900;          
 TIM_OC2Init(TIM2, &TIM_OCInitStructure);          //¸ù¾ÝTIM_OCInitStructÖÐÖ¸¶¨µÄ²ÎÊý³õʼ»¯ÍâÉèTIMx
 TIM_OC2PreloadConfig(TIM2, TIM_OCPreload_Enable); //ʹÄÜTIMxÔÚCCR2ÉϵÄԤװÔؼĴæÆ÷
 //使能TIx在ARR上的预装载寄存器
 TIM_ARRPreloadConfig(TIM2, ENABLE);          

//蜂鸣器不响              
 TIM_Cmd(TIM2, DISABLE); //½ûÖ¹TIM2ʹÄÜ

//蜂鸣器响  使能TIM2
  TIM_Cmd(TIM2, ENABLE);//ʹÄܶ¨Ê±Æ÷ 

//蜂鸣器不响
 TIM_Cmd(TIM2, DISABLE); //½ûÖ¹TIM2ʹÄÜ 

//蜂鸣器响
 TIM_Cmd(TIM2, ENABLE);//ʹÄܶ¨Ê±Æ÷ 

蜂鸣器不响
 TIM_Cmd(TIM2, DISABLE); //½ûÖ¹TIM2ʹÄÜ 
 
 
 }