STM32F103系列PWM波

话不多说，直接上我能跑通的代码

pwm.h

#ifndef _PWM_H_
#define _PWM_H_

#include "stm32f10x.h"

void PWM_Init(void);

#endif

pwm.c

#include "PWM.h"

void PWM_Init(void)
{
	GPIO_InitTypeDef 			GPIO_InitStructure;
	TIM_TimeBaseInitTypeDef  	TIM_TimeBaseStructure;
	TIM_OCInitTypeDef  			TIM_OCInitStructure;
	
	RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2 | RCC_APB1Periph_TIM3, ENABLE);
	RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);

	GPIO_InitStructure.GPIO_Pin = GPIO_Pin_1 | GPIO_Pin_2 |GPIO_Pin_3 ;
	//定时器TIM2的PWM输出通道2,3,4，TIM2,CH2,3,4.
    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);//初始化GPIO

    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6 | GPIO_Pin_7 ;
    //定时器TIM3的PWM输出通道1,2  TIM3,CH1,2。
    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);//初始化GPIO
	
	TIM_TimeBaseStructure.TIM_Period = 999;//自动重装值
	TIM_TimeBaseStructure.TIM_Prescaler =719; //时钟预分频数
	TIM_TimeBaseStructure.TIM_ClockDivision = 0;
	TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;//TIM向上计数模式
	TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure); //初始化TIM4
	
	TIM_TimeBaseStructure.TIM_Period = 999;//自动重装值
	TIM_TimeBaseStructure.TIM_Prescaler =719; //时钟预分频数
	TIM_TimeBaseStructure.TIM_ClockDivision = 0;
	TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;//TIM向上计数模式
	TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure); //初始化TIM4
	
	TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;//设置PWM模式1
    TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;//比较输出使能
    TIM_OCInitStructure.TIM_Pulse = 0; //
    TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;//输出极性为高
    TIM_OC2Init(TIM2, &TIM_OCInitStructure);//初始化TIM2_CH2
	TIM_OC3Init(TIM2, &TIM_OCInitStructure);//初始化TIM2_CH3
	TIM_OC4Init(TIM2, &TIM_OCInitStructure);//初始化TIM2_CH4
	TIM_OC1Init(TIM3, &TIM_OCInitStructure);//初始化TIM3_CH1
	TIM_OC2Init(TIM3, &TIM_OCInitStructure);//初始化TIM3_CH2
	
	TIM_OC2PreloadConfig(TIM2, TIM_OCPreload_Enable);//OC1
    TIM_OC3PreloadConfig(TIM2, TIM_OCPreload_Enable);//OC2
    TIM_OC4PreloadConfig(TIM2, TIM_OCPreload_Enable);//OC3   
    TIM_ARRPreloadConfig(TIM2, ENABLE); //使能重装寄存器
	
	TIM_OC1PreloadConfig(TIM3, TIM_OCPreload_Enable);//OC4
	TIM_OC2PreloadConfig(TIM3, TIM_OCPreload_Enable);//OC5
	TIM_ARRPreloadConfig(TIM3, ENABLE); //使能重装寄存器
	
	TIM_Cmd(TIM2, ENABLE);//使能定时器TIM2，准备工作
	TIM_Cmd(TIM3, ENABLE);//使能定时器TIM3，准备工作
}	

上述中
TIM_TimeBaseStructure.TIM_Period = 999;//自动重装值
TIM_TimeBaseStructure.TIM_Prescaler =719; //时钟预分频数
在单片机中的频率就是
72000000 / ( (999+1) * (719+1) )
=72000000 / 1000*720
=100
所以这个数值所出来的pwm波是1s / 100 = 10ms一次的波
在main中，所用到的函数为：
TIM_SetCompareX(TIMX, 150)；
其中第一个X为单片机中第几个通道，比如，ch1，则X为1
第二个X为第几个定时器
150为你在这个10ms中，多少时间是高电平。因为TIM_TimeBaseStructure.TIM_Period = 999;
所以他就是150 / （999+1）=15% 所以他就是15%的时间为高电平
例子：在pwm.c中配置了TIM3的通道2
所以函数为：TIM_SetCompare2(TIM3, 150)；