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上海市建筑业官网,seo快速排名优化方法,wordpress theme 企业,十大手游平台排行榜输出比较简介和特性 -1-只有通用/高级定时器才能输出PWM -2-占空比就是高电平所占的比例 -3-输出比较就是输出不同占空比的信号工作方式说明 -1-1- PWM工作模式 -1-2- 有效/无效电平有效电平可以设置为高或低电平，是自己配置的周期选择与计算周期重…

输出比较简介和特性

-1-只有通用/高级定时器才能输出PWM

-2-占空比就是高电平所占的比例

-3-输出比较就是输出不同占空比的信号

工作方式说明

-1-1- PWM工作模式
在这里插入图片描述

-1-2- 有效/无效电平

有效电平可以设置为高或低电平，是自己配置的

周期选择与计算

周期=重装载 * 预分频值 / 时钟频率
在这里插入图片描述
arr和psc是自己定义的时钟频率可以查看时钟树，即下图中的84MHZ

在这里插入图片描述

F1和F4采用的时钟频率

F1通过72MHZ分频

F4通过84MHZ分频

HZ代表单位时间震荡次数，如1MHZ，就是一秒震荡1000000次

代码分享（一路PWM输出，F1可直接使用）

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);	//使能定时器3时钟RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB  | RCC_APB2Periph_AFIO, ENABLE);  //使能GPIO外设和AFIO复用功能模块时钟GPIO_PinRemapConfig(GPIO_PartialRemap_TIM3, ENABLE); //Timer3部分重映射  TIM3_CH2->PB5    //设置该引脚为复用输出功能,输出TIM3 CH2的PWM脉冲波形	GPIOB.5GPIO_InitStructure.GPIO_Pin = GPIO_Pin_5; //TIM_CH2GPIO_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GPIO//初始化TIM3TIM_TimeBaseStructure.TIM_Period = arr; //设置在下一个更新事件装入活动的自动重装载寄存器周期的值TIM_TimeBaseStructure.TIM_Prescaler =psc; //设置用来作为TIMx时钟频率除数的预分频值 TIM_TimeBaseStructure.TIM_ClockDivision = 0; //设置时钟分割:TDTS = Tck_timTIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;  //TIM向上计数模式TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure); //根据TIM_TimeBaseInitStruct中指定的参数初始化TIMx的时间基数单位//初始化TIM3 Channel2 PWM模式	 TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM2; //选择定时器模式:TIM脉冲宽度调制模式2TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable; //比较输出使能TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High; //输出极性:TIM输出比较极性高TIM_OC2Init(TIM3, &TIM_OCInitStructure);  //根据T指定的参数初始化外设TIM3 OC2TIM_OC2PreloadConfig(TIM3, TIM_OCPreload_Enable);  //使能TIM3在CCR2上的预装载寄存器TIM_Cmd(TIM3, ENABLE);  //使能TIM3}

代码分享（四路PWM输出，F4可直接使用）

#include "stm32f4xx.h"TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
TIM_OCInitTypeDef  TIM_OCInitStructure;
uint16_t CCR1_Val = 333;
uint16_t CCR2_Val = 249;
uint16_t CCR3_Val = 166;
uint16_t CCR4_Val = 83;
uint16_t PrescalerValue = 0;void TIM_Config(void);void PWM_Config (void);
int main()
{TIM_Config();PWM_Config();while (1){}}void TIM_Config(void){GPIO_InitTypeDef GPIO_InitStructure;/* TIM3 clock enable */RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE);/* GPIOC clock enable */RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOC, ENABLE);/* GPIOC Configuration: TIM3 CH1 (PC6), TIM3 CH2 (PC7), TIM3 CH3 (PC8) and TIM3 CH4 (PC9) */GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6 | GPIO_Pin_7 | GPIO_Pin_8 | GPIO_Pin_9;GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz;GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP ;GPIO_Init(GPIOC, &GPIO_InitStructure); /* Connect TIM3 pins to AF2 */  GPIO_PinAFConfig(GPIOC, GPIO_PinSource6, GPIO_AF_TIM3);GPIO_PinAFConfig(GPIOC, GPIO_PinSource7, GPIO_AF_TIM3); GPIO_PinAFConfig(GPIOC, GPIO_PinSource8, GPIO_AF_TIM3);GPIO_PinAFConfig(GPIOC, GPIO_PinSource9, GPIO_AF_TIM3); }void PWM_Config (void)
{PrescalerValue = (uint16_t) ((SystemCoreClock /2) / 21000000) - 1;/* Time base configuration */TIM_TimeBaseStructure.TIM_Period = 665;TIM_TimeBaseStructure.TIM_Prescaler = PrescalerValue;TIM_TimeBaseStructure.TIM_ClockDivision = 0;TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure);/* PWM1 Mode configuration: Channel1 */TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;TIM_OCInitStructure.TIM_Pulse = CCR1_Val;TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;TIM_OC1Init(TIM3, &TIM_OCInitStructure);TIM_OC1PreloadConfig(TIM3, TIM_OCPreload_Enable);/* PWM1 Mode configuration: Channel2 */TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;TIM_OCInitStructure.TIM_Pulse = CCR2_Val;TIM_OC2Init(TIM3, &TIM_OCInitStructure);TIM_OC2PreloadConfig(TIM3, TIM_OCPreload_Enable);/* PWM1 Mode configuration: Channel3 */TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;TIM_OCInitStructure.TIM_Pulse = CCR3_Val;TIM_OC3Init(TIM3, &TIM_OCInitStructure);TIM_OC3PreloadConfig(TIM3, TIM_OCPreload_Enable);/* PWM1 Mode configuration: Channel4 */TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;TIM_OCInitStructure.TIM_Pulse = CCR4_Val;TIM_OC4Init(TIM3, &TIM_OCInitStructure);TIM_OC4PreloadConfig(TIM3, TIM_OCPreload_Enable);TIM_ARRPreloadConfig(TIM3, ENABLE);/* TIM3 enable counter */TIM_Cmd(TIM3, ENABLE);}