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目录

一、输出比较简介

二、PWM简介

三、输出比较通道（通用）

四、输出比较通道（高级）

五、输出比较模式

六、PWM基本结构 

七、PWM参数计算

八、外设介绍

8.1 舵机

8.2 直流电机及驱动

九、开发步骤

十、输出比较库函数 

十一、实验

9.1 PWM驱动LED呼吸灯

9.2 PWM驱动舵机

9.3 PWM驱动直流电机

---

一、输出比较简介

>OC（Output Compare）输出比较
>输出比较可以通过比较CNT与CCR（捕获/比较寄存器）值的关系，来对输出电平进行置1、置0或翻转的操作，用于输出一定频率和占空比的PWM波形
>每个高级定时器和通用定时器都拥有4个输出比较通道
>高级定时器的前3个通道额外拥有死区生成和互补输出的功能

二、PWM简介

>PWM（Pulse Width Modulation）脉冲宽度调制
>在具有惯性的系统中，可以通过对一系列脉冲的宽度进行调制，来等效地获得所需要的模拟参量，常应用于电机控速等领域
>PWM参数：
  频率 = 1 / Ts           占空比 = Ton / Ts           分辨率 = 占空比变化步距

三、输出比较通道（通用）

四、输出比较通道（高级）

五、输出比较模式

六、PWM基本结构 

七、PWM参数计算

八、外设介绍

8.1 舵机

8.2 直流电机及驱动

九、开发步骤

①RCC打开时钟，TIM和GPIO外设的时钟打开

②配置时基单元，包括前面的时钟源选择

③结构体配置输出比较单元（CCR，输出比较模式，极性选择，输出使能）

④配置GPIO，PWM对应GPIO初始化为复用推挽输出

⑤运行控制，启动计数器

十、输出比较库函数 

注：标@的为重要，需掌握

@===================输出比较4模块配置函数==============================

void TIM_OC1Init(TIM_TypeDef* TIMx, TIM_OCInitTypeDef* TIM_OCInitStruct);
void TIM_OC2Init(TIM_TypeDef* TIMx, TIM_OCInitTypeDef* TIM_OCInitStruct);
void TIM_OC3Init(TIM_TypeDef* TIMx, TIM_OCInitTypeDef* TIM_OCInitStruct);
void TIM_OC4Init(TIM_TypeDef* TIMx, TIM_OCInitTypeDef* TIM_OCInitStruct);

参数：①定时器；②结构体

=====================================================================

void TIM_OCStructInit(TIM_OCInitTypeDef* TIM_OCInitStruct);

//输出比较结构体赋初值

=====================配置强制输出模式（了解即可）========================

void TIM_ForcedOC1Config(TIM_TypeDef* TIMx, uint16_t TIM_ForcedAction);
void TIM_ForcedOC2Config(TIM_TypeDef* TIMx, uint16_t TIM_ForcedAction);
void TIM_ForcedOC3Config(TIM_TypeDef* TIMx, uint16_t TIM_ForcedAction);
void TIM_ForcedOC4Config(TIM_TypeDef* TIMx, uint16_t TIM_ForcedAction);

=============配置CCR寄存器的预装功能（影子寄存器）（了解即可）=============

void TIM_OC1PreloadConfig(TIM_TypeDef* TIMx, uint16_t TIM_OCPreload);
void TIM_OC2PreloadConfig(TIM_TypeDef* TIMx, uint16_t TIM_OCPreload);
void TIM_OC3PreloadConfig(TIM_TypeDef* TIMx, uint16_t TIM_OCPreload);
void TIM_OC4PreloadConfig(TIM_TypeDef* TIMx, uint16_t TIM_OCPreload);

=======================配置快速使能（了解即可）==========================

void TIM_OC1FastConfig(TIM_TypeDef* TIMx, uint16_t TIM_OCFast);
void TIM_OC2FastConfig(TIM_TypeDef* TIMx, uint16_t TIM_OCFast);
void TIM_OC3FastConfig(TIM_TypeDef* TIMx, uint16_t TIM_OCFast);
void TIM_OC4FastConfig(TIM_TypeDef* TIMx, uint16_t TIM_OCFast);

=======================外部事件清除REF信号（了解即可）===================

void TIM_ClearOC1Ref(TIM_TypeDef* TIMx, uint16_t TIM_OCClear);
void TIM_ClearOC2Ref(TIM_TypeDef* TIMx, uint16_t TIM_OCClear);
void TIM_ClearOC3Ref(TIM_TypeDef* TIMx, uint16_t TIM_OCClear);
void TIM_ClearOC4Ref(TIM_TypeDef* TIMx, uint16_t TIM_OCClear);

=======================单独设置输出比较极性=============================

void TIM_OC1PolarityConfig(TIM_TypeDef* TIMx, uint16_t TIM_OCPolarity);
void TIM_OC1NPolarityConfig(TIM_TypeDef* TIMx, uint16_t TIM_OCNPolarity);

//N高级定时器互补通道的配置
void TIM_OC2PolarityConfig(TIM_TypeDef* TIMx, uint16_t TIM_OCPolarity);
void TIM_OC2NPolarityConfig(TIM_TypeDef* TIMx, uint16_t TIM_OCNPolarity);
void TIM_OC3PolarityConfig(TIM_TypeDef* TIMx, uint16_t TIM_OCPolarity);
void TIM_OC3NPolarityConfig(TIM_TypeDef* TIMx, uint16_t TIM_OCNPolarity);
void TIM_OC4PolarityConfig(TIM_TypeDef* TIMx, uint16_t TIM_OCPolarity);

=======================单独修改输出使能参数=============================

void TIM_CCxCmd(TIM_TypeDef* TIMx, uint16_t TIM_Channel, uint16_t TIM_CCx);
void TIM_CCxNCmd(TIM_TypeDef* TIMx, uint16_t TIM_Channel, uint16_t TIM_CCxN);

=======================单独更改输出比较模式=============================

void TIM_SelectOCxM(TIM_TypeDef* TIMx, uint16_t TIM_Channel, uint16_t TIM_OCMode);

@=====================单独更改CCR寄存器值=============================

void TIM_SetCompare1(TIM_TypeDef* TIMx, uint16_t Compare1);
void TIM_SetCompare2(TIM_TypeDef* TIMx, uint16_t Compare2);
void TIM_SetCompare3(TIM_TypeDef* TIMx, uint16_t Compare3);
void TIM_SetCompare4(TIM_TypeDef* TIMx, uint16_t Compare4);

==========================补充========================================

void TIM_CtrlPWMOutputs(TIM_TypeDef* TIMx, FunctionalState NewState);

//仅高级定时器使用，在使用高级定时器输出PWM时，需要调用这个函数，使能主输出，否则PWM将不能正常输出

十一、实验

9.1 PWM驱动LED呼吸灯

PWM.c

#include "stm32f10x.h"                  // Device header/*PWM初始化*/
void PWM_Init(void)
{/*一、RCC开启时钟，TIM与GPIO时钟打开*/RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2,ENABLE);RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA,ENABLE);//	/*使用重映射(*_*)*/
//	RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO,ENABLE);
//	GPIO_PinRemapConfig(GPIO_PartialRemap1_TIM2,ENABLE);//PA0->PA15，部分重映射S
//	GPIO_PinRemapConfig(GPIO_Remap_SWJ_JTAGDisable,ENABLE);//解除JATG调试GPIO_InitTypeDef GPIO_InitStructure;GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;//复用推挽输出GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0;//(*_*)GPIO_Pin_15GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;GPIO_Init(GPIOA,&GPIO_InitStructure);/*二、配置时基单元（时钟源选择和时基单元配置）*/TIM_InternalClockConfig(TIM2);//选择内部时钟TIM_TimeBaseInitTypeDef TIM_TimeBaseInitStructure;TIM_TimeBaseInitStructure.TIM_ClockDivision = TIM_CKD_DIV1;TIM_TimeBaseInitStructure.TIM_CounterMode = TIM_CounterMode_Up;TIM_TimeBaseInitStructure.TIM_Period = 100 - 1;		//ARR自动重装器值TIM_TimeBaseInitStructure.TIM_Prescaler = 720 - 1;	//PSC预分频器值TIM_TimeBaseInitStructure.TIM_RepetitionCounter = 0;//重复计数器值TIM_TimeBaseInit(TIM2, &TIM_TimeBaseInitStructure);/*三、配置输出比较单元（CCR的值(捕获/比较器)，输出比较模式，极性选择，输出使能）*/TIM_OCInitTypeDef TIM_OCInitStructure;TIM_OCStructInit(&TIM_OCInitStructure);//给结构体所有成员赋初始值（有些用不到但是必须赋值）TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;//输出比较模式TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;//输出比较的极性TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;//输出使能TIM_OCInitStructure.TIM_Pulse = 0;//设置CCRTIM_OC1Init(TIM2,&TIM_OCInitStructure);/*四、配置GPIO，复用推挽输出*///一处已操作/*五、运行控制，启动计数器CNT*/TIM_Cmd(TIM2,ENABLE);
}/*封装函数->更改CCR值来改变占空比*/
void PWM_SetCompare1(uint16_t Compare)
{TIM_SetCompare1(TIM2,Compare);
}

PWM.h

#ifndef __PWM_H
#define __PWM_Hvoid PWM_Init(void);
void PWM_SetCompare1(uint16_t Compare);#endif

main.c

#include "stm32f10x.h"                  // Device header
#include "Delay.h"
#include "OLED.h"
#include "PWM.h"uint8_t i;int main(void)
{OLED_Init();PWM_Init();while (1){//CCR增大，逐渐变亮for (i = 0; i <= 100; i++){PWM_SetCompare1(i);Delay_ms(10);}//CCR减小，逐渐变暗for (i = 0; i <= 100; i++){PWM_SetCompare1(100 - i);Delay_ms(10);}}
}

9.2 PWM驱动舵机

实验现象：按下按键，舵机转动固定角度

PWM.c

#include "stm32f10x.h"                  // Device header/*PWM初始化*/
void PWM_Init(void)
{/*一、RCC开启时钟，TIM与GPIO时钟打开*/RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2,ENABLE);RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA,ENABLE);GPIO_InitTypeDef GPIO_InitStructure;GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;//复用推挽输出GPIO_InitStructure.GPIO_Pin = GPIO_Pin_1;GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;GPIO_Init(GPIOA,&GPIO_InitStructure);/*二、配置时基单元（时钟源选择和时基单元配置）*/TIM_InternalClockConfig(TIM2);//选择内部时钟TIM_TimeBaseInitTypeDef TIM_TimeBaseInitStructure;TIM_TimeBaseInitStructure.TIM_ClockDivision = TIM_CKD_DIV1;TIM_TimeBaseInitStructure.TIM_CounterMode = TIM_CounterMode_Up;TIM_TimeBaseInitStructure.TIM_Period = 20000 - 1;		//ARR自动重装器值TIM_TimeBaseInitStructure.TIM_Prescaler = 72 - 1;	//PSC预分频器值TIM_TimeBaseInitStructure.TIM_RepetitionCounter = 0;//重复计数器值TIM_TimeBaseInit(TIM2, &TIM_TimeBaseInitStructure);/*三、配置输出比较单元（CCR的值(捕获/比较器)，输出比较模式，极性选择，输出使能）*/TIM_OCInitTypeDef TIM_OCInitStructure;TIM_OCStructInit(&TIM_OCInitStructure);//给结构体所有成员赋初始值（有些用不到但是必须赋值）TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;//输出比较模式TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;//输出比较的极性TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;//输出使能TIM_OCInitStructure.TIM_Pulse = 0;//设置CCR（500~2500）TIM_OC2Init(TIM2,&TIM_OCInitStructure);/*四、配置GPIO，复用推挽输出*///一处已操作/*五、运行控制，启动计数器CNT*/TIM_Cmd(TIM2,ENABLE);
}/*封装函数->更改CCR值来改变占空比*/
void PWM_SetCompare2(uint16_t Compare)
{TIM_SetCompare2(TIM2,Compare);
}

PWM.h

#ifndef __PWM_H
#define __PWM_Hvoid PWM_Init(void);
void PWM_SetCompare2(uint16_t Compare);#endif

Servo.c

#include "stm32f10x.h"                  // Device header
#include "PWM.h"//舵机初始化（PWM初始化）
void Servo_Init(void)
{PWM_Init();
}/*
舵机设置角度
角度：0-180
CCR：500-2500
*/
void Servo_SetAngle(float Angle)
{PWM_SetCompare2(Angle / 180 * 2000 + 500);
}

Servo.h

#ifndef __SERVO_H
#define __SERVO_Hvoid Servo_Init(void);
void Servo_SetAngle(float Angle);#endif

Key.c

#include "stm32f10x.h"                  // Device header
#include "Delay.h"//===按键初始化===//
void Key_Init(void)
{RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB,ENABLE);GPIO_InitTypeDef GPIO_InitStructure;GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU;//上拉输入GPIO_InitStructure.GPIO_Pin = GPIO_Pin_1 | GPIO_Pin_11;GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;GPIO_Init(GPIOB,&GPIO_InitStructure);
}//===获取按键返回码===//
uint8_t Key_GetNum(void)
{uint8_t KeyNum = 0;if(GPIO_ReadInputDataBit(GPIOB,GPIO_Pin_1) == 0){Delay_ms(20);//消抖while(GPIO_ReadInputDataBit(GPIOB,GPIO_Pin_1) == 0);//如果不松手则卡着Delay_ms(20);KeyNum = 1;}	if(GPIO_ReadInputDataBit(GPIOB,GPIO_Pin_11) == 0){Delay_ms(20);//消抖while(GPIO_ReadInputDataBit(GPIOB,GPIO_Pin_11) == 0);Delay_ms(20);KeyNum = 2;}return KeyNum;
}

key.h

#ifndef __KEY_H
#define __KEY_Hvoid Key_Init(void);
uint8_t Key_GetNum(void);#endif

main.c

#include "stm32f10x.h"                  // Device header
#include "Delay.h"
#include "OLED.h"
#include "key.h"
#include "Servo.h"uint8_t KeyNum;
float Angle;int main(void)
{OLED_Init();Key_Init();Servo_Init();OLED_ShowString(1,1,"Angle:");while (1){KeyNum = Key_GetNum();if(KeyNum == 1){Angle += 30;if(Angle >180){Angle = 0;}}Servo_SetAngle(Angle);OLED_ShowNum(1,7,Angle,3);}
}

*OLED显示屏代码请参考本专栏文章STM32-OLED显示屏

9.3 PWM驱动直流电机

实验现象： 按键按下，电机加速，达到最大转速时，再按一下，最大速度反转，按下按键，电机减速

PWM.c

#include "stm32f10x.h"                  // Device header/*PWM初始化*/
void PWM_Init(void)
{/*一、RCC开启时钟，TIM与GPIO时钟打开*/RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2,ENABLE);RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA,ENABLE);GPIO_InitTypeDef GPIO_InitStructure;GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;//复用推挽输出GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2;GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;GPIO_Init(GPIOA,&GPIO_InitStructure);/*二、配置时基单元（时钟源选择和时基单元配置）*/TIM_InternalClockConfig(TIM2);//选择内部时钟TIM_TimeBaseInitTypeDef TIM_TimeBaseInitStructure;TIM_TimeBaseInitStructure.TIM_ClockDivision = TIM_CKD_DIV1;TIM_TimeBaseInitStructure.TIM_CounterMode = TIM_CounterMode_Up;TIM_TimeBaseInitStructure.TIM_Period = 100 - 1;		//ARR自动重装器值TIM_TimeBaseInitStructure.TIM_Prescaler = 36 - 1;	//PSC预分频器值TIM_TimeBaseInitStructure.TIM_RepetitionCounter = 0;//重复计数器值TIM_TimeBaseInit(TIM2, &TIM_TimeBaseInitStructure);/*三、配置输出比较单元（CCR的值(捕获/比较器)，输出比较模式，极性选择，输出使能）*/TIM_OCInitTypeDef TIM_OCInitStructure;TIM_OCStructInit(&TIM_OCInitStructure);//给结构体所有成员赋初始值（有些用不到但是必须赋值）TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;//输出比较模式TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;//输出比较的极性TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;//输出使能TIM_OCInitStructure.TIM_Pulse = 0;//设置CCRTIM_OC3Init(TIM2,&TIM_OCInitStructure);/*四、配置GPIO，复用推挽输出*///一处已操作/*五、运行控制，启动计数器CNT*/TIM_Cmd(TIM2,ENABLE);
}/*封装函数->更改CCR值来改变占空比*/
void PWM_SetCompare3(uint16_t Compare)
{TIM_SetCompare3(TIM2,Compare);
}

PWM.h

#ifndef __PWM_H
#define __PWM_Hvoid PWM_Init(void);
void PWM_SetCompare3(uint16_t Compare);#endif

Motor.c

#include "stm32f10x.h"                  // Device header
#include "PWM.h"void Motor_Init(void)
{RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA,ENABLE);GPIO_InitTypeDef GPIO_InitStructure;GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;GPIO_InitStructure.GPIO_Pin = GPIO_Pin_4 | GPIO_Pin_5;GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;GPIO_Init(GPIOA,&GPIO_InitStructure);PWM_Init();
}/*设置电机速度（-100~100）*/
void Motor_SetSpeed(int8_t Speed)
{if(Speed >= 0){GPIO_SetBits(GPIOA,GPIO_Pin_4);GPIO_ResetBits(GPIOA,GPIO_Pin_5);PWM_SetCompare3(Speed);}else{GPIO_SetBits(GPIOA,GPIO_Pin_5);GPIO_ResetBits(GPIOA,GPIO_Pin_4);PWM_SetCompare3(-Speed);}
}

Motor.h

#ifndef __PWM_H
#define __PWM_Hvoid Motor_Init(void);
void Motor_SetSpeed(int8_t Speed);#endif

*按键与OLED显示屏的代码参考之前实验代码