蓝桥嵌入式之 TIM的PWM模式_Again

版权声明：转载记得声明~~~ :) https://blog.csdn.net/ReCclay/article/details/87627268

工程代码可见Github<传送门>

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1、主要代码

main.c

/*******************************************************************************
* 文件名：main.c
* 描  述：
* 作  者：CLAY
* 版本号：v1.0.0
* 日  期: 2019年2月18日
* 备  注：修改后的LCD例程
*         PA1 (TIM2_CH2) 输出频率500Hz，占空比60%的方波
*******************************************************************************
*/

#include "stm32f10x.h"
#include "lcd.h"
#include "e2prom.h"
#include "stdio.h"
#include "i2c.h"
#include "adc.h"
#include "rtc.h"
#include "usart2.h"
#include "pwm.h"

u32 TimingDelay = 0;
u8 RxdCnt = 0;
u8 RxdOver = 0;
u8 RxdBuf[20];
void Delay_Ms(u32 nTime);
u8 RTC_Flag = 0;

//Main Body
int main(void)
{	
	STM3210B_LCD_Init();
	LCD_Clear(Blue);
	LCD_SetBackColor(Blue);
	LCD_SetTextColor(White);
	
	SysTick_Config(SystemCoreClock/1000);
	
	PWM_Init(500, 60);//500Hz 60%方波
	
	while(1)
	{
		
	}
}

//
void Delay_Ms(u32 nTime)
{
	TimingDelay = nTime;
	while(TimingDelay != 0);	
}

pwm.c

#include "stm32f10x.h"

void PWM_Init(u32 freq, u8 duty)
{
	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_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);
	
	TIM_TimeBaseStructure.TIM_Prescaler = 72-1;//72分频
	TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
	TIM_TimeBaseStructure.TIM_Period = arr - 1;//周期值
	TIM_TimeBaseStructure.TIM_ClockDivision = 0;
	TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure);//TIM2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) * duty / 100;//占空比
	TIM_OC2Init(TIM2, &TIM_OCInitStructure);//TIM2_CH2
	
	TIM_Cmd(TIM2, ENABLE);//使能TIM2
}

pwm.h

#ifndef _PWM_H
#define _PWM_H


void PWM_Init(u32 freq, u8 duty);

#endif

二、注意事项

1、TIM的PWM模式通道设置需要对应

TIM_OC2Init(TIM2, &TIM_OCInitStructure);//TIM2_CH2

第2通道就要写TIM_OC2Init，同理，第1通道就写TIM_OC1Init

2、由频率值计算周期值

arr = 1000000 / freq;//计算频率对应的周期值