STM32f4日记1之输出pwm波（用按键调整频率，占空比，可用示波器观察结果）
选用板子：正点原子stm32f407zgt6迷你板
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使用到OLED显示当前输出的频率和占空比
实验仪器：示波器（黑色接地，红色接PF8）
使用公母头杜邦线，可以用公公头跟母母头拼出来

以下是pwm.c里的代码（定时器Tim13 IO口为PF8）

void TIM13_PWM_Init(u32 arr,u32 psc)//入口参数arr psc分频系数根据单片机型号定在main.c里使用
{		 					 
	
	
	GPIO_InitTypeDef GPIO_InitStructure;
	TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
	TIM_OCInitTypeDef  TIM_OCInitStructure;
	
	RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM13,ENABLE);  	
	RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOF, ENABLE); 	
	
	GPIO_PinAFConfig(GPIOF,GPIO_PinSource8,GPIO_AF_TIM13); 
	GPIO_InitStructure.GPIO_Pin = GPIO_Pin_8;           //GPIOF8
	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;        //复用
	GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz;	//100MHz
	GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;      //pp
	GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;        //上拉默认高电平
	GPIO_Init(GPIOF,&GPIO_InitStructure);              //PF8
	  
	TIM_TimeBaseStructure.TIM_Prescaler=psc;  //设置分频系数
	TIM_TimeBaseStructure.TIM_CounterMode=TIM_CounterMode_Up; //定时器向上计数
	TIM_TimeBaseStructure.TIM_Period=arr;   //设置arr
	TIM_TimeBaseStructure.TIM_ClockDivision=TIM_CKD_DIV1; 
	
	TIM_TimeBaseInit(TIM13,&TIM_TimeBaseStructure);//
	
	//TIM13 Channel1  
	TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1; //pwm1模式
 	TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
	TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High; //极性高
	TIM_OC1Init(TIM13, &TIM_OCInitStructure);  //初始化tim13  oc1

	TIM_OC1PreloadConfig(TIM13, TIM_OCPreload_Enable);  //
 
  TIM_ARRPreloadConfig(TIM13,ENABLE);//使能arr 
	
	TIM_Cmd(TIM13, ENABLE);  //使能tim13
 
										  
}  

以下是pwm.h里面的代码

#ifndef _TIMER_H
#define _TIMER_H
#include "sys.h"

void TIM13_PWM_Init(u32 arr,u32 psc);
#endif

以下是主函数里面的代码
代码功能：
初始占空比1%
初始频率1500
按下key0占空比每次加2
按下wkup频率每次加100当频率大于1500清为100

#include "sys.h"
#include "delay.h"
//#include "timer.h"
#include "led.h"
#include "string.h"
#include "pwm.h"
#include "key.h"
#include "usart.h"
#include "oled.h"
// #include "waishekey.h"

//extern u8  TIM5CH1_CAPTURE_STA;		
//extern u8  count;              
//extern u32	TIM5CH1_CAPTURE_UP1;	
//extern u32	TIM5CH1_CAPTURE_UP2;	
//extern u32	TIM5CH1_CAPTURE_DOWN;	//这些是为输入捕获准备的请忽略
	
// PF8  用来接示波器
// PE5  用来接信号发生器，本实验不用
int main(void)
{ 
	//u32 temp_f=0;  
	//float temp_d=0;
	
	u8 key;           
	u8 key1;
	int t=1500;   //
	int duty=1;   //
	
	
	char buffer1[100];
	char buffer2[100];
	char buffer3[100];
	char buffer4[100];
 

	
	NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);//设置中断
	
	TIM13_PWM_Init(1500-1,84-1);  //最重要的初始化    arr1000   设置TIM13初始arr1500    分频84
	
	
	delay_init(168);  //初始化delay
	
	KEY_Init();  //初始化键盘
	uart_init(115200);	//´初始化串口本实验不用
 	  OLED_Init();				//初始化oled
	  OLED_Clear();
		
		
	//TIM5_CH1_Cap_Init(0XFFFFFFFF,42-1); //输入捕获,本实验不用
 
   	
	//sprintf(buffer1,"in duty:%5.1f%%",temp_d);
	//sprintf(buffer2,"in freq:%.1uHZ",temp_f);
	
	
	sprintf(buffer3,"out duty:%3d%%",duty);
	sprintf(buffer4,"out freq:%dHZ",t);
	
	


	
      while(1)
     {     
  
		
		//sprintf(buffer1,"in duty:%5.1f%%",temp_d);
	     //sprintf(buffer2,"in freq:%.1uHZ", temp_f);
			 sprintf(buffer3,"out duty:%3d%%",duty);
	    sprintf(buffer4,"out freq:%dHZ",t);
      //OLED_ShowString(0,0,buffer1,16);
	     //OLED_ShowString(0,16,buffer2,16);
	
			 OLED_ShowString(0,32,buffer3,16);
	     OLED_ShowString(0,48,buffer4,16);
			 		OLED_Refresh();
			 
	
 		
		
		key=KEY_Scan(0);
			 if(key)
		{						   
			    switch(key)
			 {				 
				case WKUP_PRES:	//
			t+=100;
			if(t>1500)t=100;
			TIM_SetCompare1(TIM13,1000000/t*(duty/100.0));
	    TIM_SetAutoreload(TIM13,1000000/t-1);
				break;
				
				
				case KEY0_PRES:	//
					duty+=2;
			if(duty>100)duty=0;
			TIM_SetCompare1(TIM13,1000000/t*(duty/100.0));
				break;
			 }
		 
  	}

	

}





}

下一篇文章会讲输入捕获实验，用到信号发生器（可将两者综合一个输出pwm一个捕获pwm，就不用仪器了）

敬请期待---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

作者:shawn

2020.12.19 00:37