PWM普通输出模式和PWM输出比较模式

#PWM普通输出模式
特点：同一定时器中，不同通道下，输出的频率固定，占空比可变，即定时器一中的通道一输出的方波是1KHZ，那么通道二中输出也是1KHZ的方波
##代码
先看初始化部分

#include "stm32f10x.h"
void PWM_Init(u32 freq, u8 duty1,u8 duty2)
{
	u32 arr;
	GPIO_InitTypeDef GPIO_InitStructure;
	TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
	TIM_OCInitTypeDef  TIM_OCInitStructure;
	
	arr = 1000000 / freq;//计算频率对应的周期值
	
	RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);
	RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE);
	
	GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6|GPIO_Pin_7;
	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;//强推挽输出
	GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
	GPIO_Init(GPIOA, &GPIO_InitStructure);
	
	TIM_TimeBaseStructure.TIM_Period = arr - 1;//周期值
	TIM_TimeBaseStructure.TIM_Prescaler = 72-1;//72分频
	TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
	TIM_TimeBaseStructure.TIM_ClockDivision = 0;
	TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure);//TIM3定时器
	
	TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM2;//极性
	TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_Low;//极性
	TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
	TIM_OCInitStructure.TIM_Pulse = (arr-1) * duty1 / 100;//占空比
	TIM_OC1Init(TIM3, &TIM_OCInitStructure);//TIM3_CH1->PA6

	TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM2;//极性
	TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_Low;//极性
	TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
	TIM_OCInitStructure.TIM_Pulse = (arr-1) * duty2 / 100;//占空比
	TIM_OC2Init(TIM3, &TIM_OCInitStructure);//TIM3_CH2->PA7
	
	TIM_Cmd(TIM3, ENABLE);//使能TIM3
}

不需要定时器中断函数配置

PWM_Init(1000,40,80);

#PWM输出比较模式
特点：同一定时器中可以产生不同的频率，不同占空比的方波，甚至还可以产生不同相位的方波
若想了解输出比较模式思想，关注以下博文

https://blog.csdn.net/qq_34952376/article/details/81172535

##代码
初始化部分

#include "stm32f10x.h"
#include"compare.h"
u32 CH2_Val;
u32 CH2_Duty;//我日哦，溢出了注意这里是占空比对应的计数值并不是小于100的数！！！

void PWM_OC_Init(u32 freq, u8 duty)
{
	GPIO_InitTypeDef GPIO_InitStructure;
	NVIC_InitTypeDef NVIC_InitStructure;
	TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
	TIM_OCInitTypeDef  TIM_OCInitStructure;
	
	CH2_Val = 1000000 / freq;//频率对应的计数值
	CH2_Duty = CH2_Val * duty / 100;//占空比对应的计数值
	
	//别忘了先开启对应时钟
	RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);
	RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);
	
	GPIO_InitStructure.GPIO_Pin = GPIO_Pin_1;
	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;//强推挽输出
	GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
	GPIO_Init(GPIOA, &GPIO_InitStructure);
	
	//输出比较需要用到定时器中断，所以设置了中断向量
	NVIC_InitStructure.NVIC_IRQChannel = TIM2_IRQn;
	NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
	NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
	NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
	NVIC_Init(&NVIC_InitStructure);
	
	TIM_TimeBaseStructure.TIM_Period = 0xFFFF;//总的值设置为0xFFFF
	TIM_TimeBaseStructure.TIM_Prescaler = 71;
	TIM_TimeBaseStructure.TIM_ClockDivision = 0;
	TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
	TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure);
	
	TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_Toggle;//转换模式
	TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
	TIM_OCInitStructure.TIM_Pulse = CH2_Val;
	TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_Low;
	TIM_OC2Init(TIM2, &TIM_OCInitStructure);//注意这里是OC2
	
	TIM_SetCounter(TIM2, 0);//计数器清0
	TIM_SetCompare2(TIM2, 0);//设置比较值
	
	TIM_Cmd(TIM2, ENABLE);//开启定时器
	TIM_ITConfig(TIM2, TIM_IT_CC2, ENABLE);//开启定时器中断
	
}

定时器部分

extern u32 CH2_Val;
extern u32 CH2_Duty;

void TIM2_IRQHandler(void)
{
	u16 capture = 0;
	static u8 flag = 0;
	
	if(TIM_GetITStatus(TIM2, TIM_IT_CC2) == 1)
	{
		TIM_ClearITPendingBit(TIM2, TIM_IT_CC2);
		
		capture = TIM_GetCapture2(TIM2);//获取通道2的当前的比较值
		if(flag)
		{
			TIM_SetCompare2(TIM2, capture+CH2_Duty);//设置通道2的值为：当前比较值+高电平
		}
		else
		{
			TIM_SetCompare2(TIM2, capture+(CH2_Val-CH2_Duty));//设置通道2的值为：当前比较值+低电平
		}
		flag ^= 1;//flag在0和1直接变化
	}
}
主函数
PWM_OC_Init(1000,40);

*这里还想再说下相位不同的方法：
相位不同就是指两路方波输出的时间点不同，通过设置初始化函数里的TIM_SetCompare（xxx）函数，改变比较值，必须通过输出比较模式才能产生相位不同的方波。