1.注意事项
IM_TimeBaseInitTypeDef结构体里面有5个成员，TIM6和TIM7的寄存器里面只TIM_Prescaler和TIM_Period，所以使用TIM6和TIM7的时候只需初始化这两个成员即可，另外三个成员是通用定时器和高级定时器才有。
结构体当中的对比：
typedef struct
{ TIM_Prescaler 都有
TIM_CounterMode TIMx,x[6,7]没有，其他都有
TIM_Period 都有
TIM_ClockDivision TIMx,x[6,7]没有，其他都有
TIM_RepetitionCounter TIMx,x[1,8,15,16,17]才有
}TIM_TimeBaseInitTypeDef;
2. PWM信号 周期和占空比的计算
// ARR ：自动重装载寄存器的值
// CLK_cnt：计数器的时钟，等于 Fck_int / (psc 1) = 72M/(psc 1)
// PWM 信号的周期 T = ARR * (1/CLK_cnt) = ARR(PSC 1) / 72M
// 占空比P=CCR/(ARR 1)
pwm.c
代码语言：javascript复制void Tim3Pwm1Init(void)
{
GPIO_InitTypeDef GPIO_InitStructure;
TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
TIM_OCInitTypeDef TIM_OCInitStructure;
//输出比较通道初始化
RCC_APB1PeriphClockCmd(OUTPUT_PWM1_TIM_CLK,ENABLE);
RCC_APB2PeriphClockCmd(OUTPUT_PWM1_GPIO_CLK,ENABLE);
GPIO_InitStructure.GPIO_Pin = OUTPUT_PWM1_PIN;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(OUTPUT_PWM1_PORT,&GPIO_InitStructure);
TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1; //时钟分频因子
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up; //计数器技术模式，向上计数
TIM_TimeBaseStructure.TIM_Period = 500-1;
TIM_TimeBaseStructure.TIM_Prescaler = 720-1;
TIM_TimeBaseStructure.TIM_RepetitionCounter = 0; //重复计数器的值
TIM_TimeBaseInit(OUTPUT_PWM1_TIM,&TIM_TimeBaseStructure);
TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1; //PWM1模式
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable; //输出使能
TIM_OCInitStructure.TIM_Pulse = 0;
TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High; //输出通道电平极性配置
//输出比较通道
TIM_OC1Init(OUTPUT_PWM1_TIM,&TIM_OCInitStructure);
TIM_OC1PreloadConfig(OUTPUT_PWM1_TIM,TIM_OCPreload_Enable);
TIM_ARRPreloadConfig(OUTPUT_PWM1_TIM,ENABLE);
TIM_Cmd(OUTPUT_PWM1_TIM,ENABLE); //使能计数器
}
void Tim3Pwm1(u32 Duty)
{
TIM_SetCompare1(OUTPUT_PWM1_TIM,Duty);
}pwm.h
代码语言：javascript复制#ifndef _BSP_PWM_H_
#define _BSP_PWM_H_
#include "stm32f10x.h"
//PWM1
#define OUTPUT_PWM1_TIM_CLK RCC_APB1Periph_TIM3
#define OUTPUT_PWM1_GPIO_CLK RCC_APB2Periph_GPIOA
#define OUTPUT_PWM1_PIN GPIO_Pin_6
#define OUTPUT_PWM1_PORT GPIOA
#define OUTPUT_PWM1_TIM TIM3
void Tim3Pwm1Init(void);
//设置占空比
void Tim3Pwm1(u32 Duty);
#endif
