完整工程代码已放到百度网盘，链接如下：

链接：https://pan.baidu.com/s/16zcnfLt2iYlrDdN-N6tKbA 
提取码：dn54

一、L298N电机驱动板

电源引脚

VCC 外接直流电源引脚，电压范围在5~35V之间
GND GND是接地引脚，连接到电源负极
5V 驱动芯片内部逻辑供电引脚，如果安装了5V跳帽，则此引脚可输出5V电压，为微控板或其他电路提供电力供给，如果拔掉5V跳帽，则需要独立外接5V电源

控制引脚

1. IN1 & IN2 电机驱动器A的输入引脚，控制电机A转动及旋转角度
   IN1输入高电平HIGH，IN2输入低电平LOW，对应电机A正转
   IN1输入低电平LOW，IN2输入高电平HIGH，对应电机A反转
   IN1、IN2同时输入高电平HIGH或低电平LOW，对应电机A停止转动
   调速就是改变IN1、IN2高电平的占空比（需拔掉ENA处跳帽）

2. IN3 & IN4 电机驱动器B的输入引脚，控制电机B转动及旋转角度
   IN3输入高电平HIGH，IN4输入低电平LOW，对应电机B正转
   IN3输入低电平LOW，IN4输入高电平HIGH，对应电机B反转
   IN3、IN4同时输入高电平HIGH或低电平LOW，对应电机B停止转动
   调速就是改变IN3、IN4高电平的占空比（需拔掉ENB处跳帽）

输出引脚

1. OUT1 & OUT2 电机驱动器A的输出引脚，接直流电机A或步进电机的A+和A-
2. OUT3 & OUT3 电机驱动器B的输出引脚，接直流电机B或步进电机的B+和B-

调速控制引脚

1. ENA 电机A调速开关引脚，拔掉跳帽，使用PWM对电机A调速，插上电机A高速运行
2. ENB 电机B调速开关引脚，拔掉跳帽，使用PWM对电机B调速，插上电机B高速运行

OUT1、OUT2和OUT3、OUT4之间分别接两个直流电机Motor1、Motor2，IN1、IN2、IN3、IN4引脚从单片机接入控制电平，控制电机的正反转，ENA、ENB接控制使能端，控制电机调速，L298N控制逻辑关系图如下：

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二、STM32的PWM输出

1、通用定时器（TIM2 ~ TIM5）
每个定时都有 4个独立通道作为输出

2、高级控制定时器（TIM1 & TIM8）
该款定时器可产生7路 PWM输出：

3.STM32F1的TIM3输出引脚
本文用到STM32F1的TIM3的通道1~4，下面对TIM3的引脚作简要介绍：
本实验选择没有重映像的四个引脚，即PA6、PA7、PB0、PB1（有无重映像会在TIM3初始化部分的代码有所体现）

三、硬件连接

本设计用到两个L298N驱动板，四个小黄电机，一块STM32F103ZET6开发板
第一块L298N接左前电机和左后电机：
ENA—PA6，ENB—PA7
左前电机：IN1—PB7，IN2—PB6
左后电机：IN3—PB9，IN4—PB2

第二块L298N接右前电机和右后电机：
ENA—PB0，ENB—PB1
左前电机：IN1—PB13，IN2—PB12
左后电机：IN3—PB15，IN4—PB14

四、主要代码

timer.c

#include "timer.h"
#include "led.h"
#include "usart.h"

void TIM3_Int_Init(u16 arr,u16 psc)
{
  TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
	NVIC_InitTypeDef NVIC_InitStructure;

	RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE); 

	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_ITConfig(TIM3,TIM_IT_Update,ENABLE ); 
	TIM_Cmd(TIM3, ENABLE);  							 
}

//TIM3 PWM部分初始化
//PWM输出初始化
//arr:自动重装值
//psc:时钟预分频数

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);
 	RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB  | RCC_APB2Periph_GPIOA | RCC_APB2Periph_AFIO, ENABLE); 
	
		//GPIO_PinRemapConfig(GPIO_PartialRemap_TIM3, ENABLE); //这句话是正点原子官方例程“PWM输出实验”中给的，目的是Timer3部分重映射，将TIM3_CH2->PB5。本实验不用重映像


//设置PA6和PA7为复用输出功能，输出TIM3 CH1和TIM3 CH2的PWM脉冲波形
	GPIO_InitStructure.GPIO_Pin = GPIO_Pin_7 |GPIO_Pin_6; 
	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;//复用推挽输出
	GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
	GPIO_Init(GPIOA, &GPIO_InitStructure);

//设置PB0和PB1为复用输出功能，输出TIM3 CH3和TIM3 CH4的PWM脉冲波形
	GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0 |GPIO_Pin_1; 
	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;//复用推挽输出 
	GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
	GPIO_Init(GPIOB, &GPIO_InitStructure);
	
//初始化TIM3	
	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); 
	
	//初始化TIM3 Channel 1 PWM	 
	TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM2; 
 	TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable; 
	TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High; 
	TIM_OC1Init(TIM3, &TIM_OCInitStructure);
	TIM_OC1PreloadConfig(TIM3, TIM_OCPreload_Enable);
 
 	//初始化TIM3 Channel 2 PWM	 
	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); 
 
  	//初始化TIM3 Channel 3 PWM	 
	TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM2;
 	TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable; 
	TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High; 
	TIM_OC3Init(TIM3, &TIM_OCInitStructure);  
	TIM_OC3PreloadConfig(TIM3, TIM_OCPreload_Enable); 
 
   	//初始化TIM3 Channel 4 PWM	 
	TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM2; 
 	TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable; 
	TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High; 
	TIM_OC4Init(TIM3, &TIM_OCInitStructure); 
	TIM_OC4PreloadConfig(TIM3, TIM_OCPreload_Enable); 
	
	TIM_ARRPreloadConfig(TIM3,ENABLE);//使能自动重装载寄存器，arr的预装载
	TIM_Cmd(TIM3, ENABLE);//使能TIM3 
}

timer.h

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

void TIM3_Int_Init(u16 arr,u16 psc);
void TIM3_PWM_Init(u16 arr,u16 psc);
#endif

MTR_GPIO.c（电机驱动部分）

#include "MTR_GPIO.h"

//刹车
void MTR_CarBrakeAll(void){
	MTR1_BRAKE;
	MTR2_BRAKE;
	MTR3_BRAKE;
	MTR4_BRAKE;
}

//右转
void MTR_CarRight(void){
	MTR1_CW;
	MTR2_CW;
	MTR3_CCW;
	MTR4_CCW;
}

//左转
void MTR_CarLeft(void){
	MTR1_CCW;
	MTR2_CCW;
	MTR3_CW;
	MTR4_CW;
}

//后退
void MTR_CarBack(void){
	MTR1_CCW;
	MTR2_CCW;
	MTR3_CCW;
	MTR4_CCW;
}

//前进 
void MTR_CarForward(void){
	MTR1_CW;
	MTR2_CW;
	MTR3_CW;
	MTR4_CW;
}

void MTR_GPIOInit(void){
	GPIO_InitTypeDef GPIO_InitStructure;
	RCC_APB2PeriphClockCmd(MTR1_GPIO_CLK|MTR2_GPIO_CLK|MTR3_GPIO_CLK|MTR4_GPIO_CLK,ENABLE);
	GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;


	//电机1
	GPIO_InitStructure.GPIO_Pin = MTR1_GPIO_PIN;
	GPIO_Init(MTR1_GPIO_PORT, &GPIO_InitStructure);
	//电机2
	GPIO_InitStructure.GPIO_Pin = MTR2_GPIO_PIN;
	GPIO_Init(MTR2_GPIO_PORT, &GPIO_InitStructure);
	//电机3
	GPIO_InitStructure.GPIO_Pin = MTR3_GPIO_PIN;
	GPIO_Init(MTR3_GPIO_PORT, &GPIO_InitStructure);
	//电机4
	GPIO_InitStructure.GPIO_Pin = MTR4_GPIO_PIN;
	GPIO_Init(MTR4_GPIO_PORT, &GPIO_InitStructure);
}

MTR_GPIO.h

#ifndef __MTR_GPIO_H
#define __MTR_GPIO_H

#include "stm32f10x.h"


#define MTR1_GPIO_PORT		GPIOB
#define MTR1_GPIO_CLK 	    RCC_APB2Periph_GPIOB
#define MTR1_GPIO_PIN		GPIO_Pin_6|GPIO_Pin_7
#define MTR1_CW				{GPIO_ResetBits(MTR1_GPIO_PORT,GPIO_Pin_6);GPIO_SetBits(MTR1_GPIO_PORT,GPIO_Pin_7);}
#define MTR1_CCW			{GPIO_SetBits(MTR1_GPIO_PORT,GPIO_Pin_6);GPIO_ResetBits(MTR1_GPIO_PORT,GPIO_Pin_7);}
#define MTR1_BRAKE			GPIO_ResetBits(MTR1_GPIO_PORT,MTR1_GPIO_PIN);

#define MTR2_GPIO_PORT    	GPIOB
#define MTR2_GPIO_CLK 	    RCC_APB2Periph_GPIOB
#define MTR2_GPIO_PIN		GPIO_Pin_2|GPIO_Pin_9
#define MTR2_CW				{GPIO_ResetBits(MTR2_GPIO_PORT,GPIO_Pin_2);GPIO_SetBits(MTR2_GPIO_PORT,GPIO_Pin_9);}
#define MTR2_CCW			{GPIO_SetBits(MTR2_GPIO_PORT,GPIO_Pin_2);GPIO_ResetBits(MTR2_GPIO_PORT,GPIO_Pin_9);}
#define MTR2_BRAKE			GPIO_ResetBits(MTR2_GPIO_PORT,MTR2_GPIO_PIN);

#define MTR3_GPIO_PORT    	GPIOB
#define MTR3_GPIO_CLK 	    RCC_APB2Periph_GPIOB
#define MTR3_GPIO_PIN		GPIO_Pin_12|GPIO_Pin_13
#define MTR3_CW				{GPIO_ResetBits(MTR3_GPIO_PORT,GPIO_Pin_12);GPIO_SetBits(MTR3_GPIO_PORT,GPIO_Pin_13);}
#define MTR3_CCW			{GPIO_SetBits(MTR3_GPIO_PORT,GPIO_Pin_12);GPIO_ResetBits(MTR3_GPIO_PORT,GPIO_Pin_13);}
#define MTR3_BRAKE			GPIO_ResetBits(MTR3_GPIO_PORT,MTR3_GPIO_PIN);

#define MTR4_GPIO_PORT    	GPIOB
#define MTR4_GPIO_CLK 	    RCC_APB2Periph_GPIOB
#define MTR4_GPIO_PIN		GPIO_Pin_14|GPIO_Pin_15
#define MTR4_CW				{GPIO_ResetBits(MTR4_GPIO_PORT,GPIO_Pin_14);GPIO_SetBits(MTR4_GPIO_PORT,GPIO_Pin_15);}
#define MTR4_CCW			{GPIO_SetBits(MTR4_GPIO_PORT,GPIO_Pin_14);GPIO_ResetBits(MTR4_GPIO_PORT,GPIO_Pin_15);}

#define MTR4_BRAKE			GPIO_ResetBits(MTR4_GPIO_PORT,MTR4_GPIO_PIN);

void MTR_CarBrakeAll(void);
void MTR_CarRight(void);
void MTR_CarLeft(void);
void MTR_CarBack(void);
void MTR_CarForward(void);
void MTR_GPIOInit(void);

#endif

main.c

#include "delay.h"
#include "key.h"
#include "sys.h"
#include "usart.h"
#include "timer.h"
#include "MTR_GPIO.h"

//主函数改编自正点原子“PWM输出实验”，驱动四个电机输出PWM信号即电机转速可变
 int main(void)
 {		
 	u16 led0pwmval=0;
	u8 dir=1;	
	delay_init();	    	 	  
	NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2); 	 
	uart_init(115200);
 	TIM3_PWM_Init(899,0);	 //不分频，PWM频率=72000000/900=80Khz
   MTR_GPIOInit();	
	 while(1)
	{
 		delay_ms(10);	 
		if(dir)led0pwmval++;
		else led0pwmval--;
		MTR_CarForward();
 		if(led0pwmval>800)dir=0;
		if(led0pwmval==0)dir=1;										 
		TIM_SetCompare1(TIM3,led0pwmval);	
		TIM_SetCompare2(TIM3,led0pwmval);	
		TIM_SetCompare3(TIM3,led0pwmval);	
		TIM_SetCompare4(TIM3,led0pwmval);	
	}	 
 }

有需要电子类设计，如STM32单片机设计或OpenMV图像处理等指导的，可私聊~