通用定时器(中断功能和PWM输出)

目录：

1：概述

2：常用中断功能

3：PWM输出 

1：概述

在开发中，定时器的应用很广泛，简单总结为三个方面：

1.1：中断功能的应用，常用的是利用定时器中断，实现定时、记时、延时、超时判断，前面博文中有总结过内核定时器的各种使用的方法；

1.2：比较输出，常用应用就是PWM输出，用脉宽调制来实现led、电机等的控制；

1.3：输入捕获，可以抓取输入的方波信号，统计波形周期和占空比，最常见利用就是门控，将外部模拟量转化为数字量(定时器的计数值)；

2：常用中断功能

定时器的初始化详细参考手册，主要的一点是确定定时器的溢出周期，利用公式：Tout = (arr+1)*(psc+1)/Tclk，可计算出定时器的溢出频率；

如下代码实现：在中断函数中实现led翻转，翻转频率1HZ，既led闪烁频率1HZ；

timer_driver.c

#include "timer_driver.h"
#include "led_driver.h"

void TIM3_Init(unsigned int arr,unsigned int psc)
{
  TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
	NVIC_InitTypeDef NVIC_InitStructure;
	TIM_OCInitTypeDef TIM_OCInitStruct;
	
	GPIO_PinRemapConfig(GPIO_PartialRemap_TIM3, ENABLE); //将TIM3的CH2映射到PB5上
	
	//定时器TIM3初始化
	TIM_TimeBaseStructure.TIM_Period = arr; 
	TIM_TimeBaseStructure.TIM_Prescaler =psc;
	TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1;
	TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up; 
	TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure);
	
	TIM_ITConfig(TIM3,TIM_IT_Update,ENABLE ); //使能指定的TIM3中断,允许更新中断

	//中断优先级NVIC设置
	NVIC_InitStructure.NVIC_IRQChannel = TIM3_IRQn;  //TIM3中断
	NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 3;  //先占优先级0级
	NVIC_InitStructure.NVIC_IRQChannelSubPriority = 3;  //从优先级3级
	NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; //IRQ通道被使能
	NVIC_Init(&NVIC_InitStructure);  //初始化NVIC寄存器

	TIM_Cmd(TIM3, ENABLE);  //使能TIMx		
}

unsigned char flag = 0;
void TIM3_IRQHandler(void) 
{
		flag = !flag;
		if(flag == 0)
		{
			LED1_ON;
			LED2_ON;
			LED3_ON;
		}
		else
		{
			LED1_OFF;
			LED2_OFF;
			LED3_OFF;
		}
		TIM_ClearITPendingBit(TIM3,TIM_IT_Update);
}

main.c

#include "stm32f10x.h"
#include "timer_driver.h"
#include "led_driver.h"
#include "systick_driver.h"
#include "key_board.h"

unsigned int led_pwm_ctr_cnt = 0;
unsigned int led_pwm = 0;

/*外设时钟初始化*/
void RCC_PeriphClock_Config(void)
{
	/*GPIO口时钟初始化*/
	RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB | RCC_APB2Periph_GPIOD, ENABLE);
	RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE);
}

int main()
{
	NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);        //设置中断优先级分组
	SysTick_Init(INT_10MS,SysTick_CLKSource_HCLK_Div8);    //内核滴答定时器配置,用于led任务轮循 
	RCC_PeriphClock_Config();
	Led_Init();                                            //led灯初始化 
	TIM3_Init(9999,7199);                                  //定时器3初始化,溢出频率为1hz
	
	while(1)
	{
		;
	}
}

pwm输出需确定两点：PWM输出波形的周期，PWM输出波形的占空比，具体需要设置PWM波形的有效电平和PWM输出模式；

如下代码实现1khz的pwm波形输出，通过安检可以改变pwm波的占空比；

timer_driver.c

#include "timer_driver.h"
#include "led_driver.h"

void TIM3_Init(unsigned int arr,unsigned int psc)
{
  TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
	TIM_OCInitTypeDef TIM_OCInitStruct;
	
	GPIO_PinRemapConfig(GPIO_PartialRemap_TIM3, ENABLE); //将TIM3的CH2映射到PB5上
	
	//定时器TIM3初始化
	TIM_TimeBaseStructure.TIM_Period = arr; 
	TIM_TimeBaseStructure.TIM_Prescaler =psc;
	TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1;
	TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up; 
	TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure);
	
	//PWM CH2输出初始化
	TIM_OCInitStruct.TIM_OCMode = TIM_OCMode_PWM2;                /*开发板高电平led灯亮,因为设置向上计数方式,并且设置OC1有效电平为高电平,根据手册，设置为PWM模式2*/
	TIM_OCInitStruct.TIM_OutputState = TIM_OutputState_Enable;    /*设置OC2输出使能*/
	TIM_OCInitStruct.TIM_OCPolarity = TIM_OCPolarity_Low;         /*设置OC2有效电平为低电平*/
	TIM_OC2Init(TIM3, &TIM_OCInitStruct);
	
//	//PWM CH1输出初始化
//	TIM_OCInitStruct.TIM_OCMode = TIM_OCMode_PWM2;                /*开发板高电平led灯亮,因为设置向上计数方式,并且设置OC1有效电平为高电平,根据手册，设置为PWM模式2*/
//	TIM_OCInitStruct.TIM_OutputState = TIM_OutputState_Enable;    /*设置OC1输出使能*/
//	TIM_OCInitStruct.TIM_OCPolarity = TIM_OCPolarity_Low;         /*设置OC1有效电平为低电平*/
//	TIM_OC1Init(TIM3, &TIM_OCInitStruct);

	TIM_Cmd(TIM3, ENABLE);  //使能TIMx		

	TIM_OC2PreloadConfig(TIM3, TIM_OCPreload_Enable); /*开启输出比较2的预装载功能*/ 
	//TIM_OC1PreloadConfig(TIM3, TIM_OCPreload_Enable); /*开启输出比较2的预装载功能*/ 
	
	TIM_SetCompare2(TIM3, 500);
	//TIM_SetCompare1(TIM3, 500);
}

main.c

#include "stm32f10x.h"
#include "timer_driver.h"
#include "led_driver.h"
#include "systick_driver.h"
#include "key_board.h"

unsigned int led_pwm_ctr_cnt = 0;
unsigned int led_pwm = 500;

/*外设时钟初始化*/
void RCC_PeriphClock_Config(void)
{
	/*GPIO口时钟初始化*/
	RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_GPIOB | RCC_APB2Periph_GPIOC | RCC_APB2Periph_AFIO, ENABLE);
	RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE);
}

int main()
{
	NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);        //设置中断优先级分组
	SysTick_Init(INT_10MS,SysTick_CLKSource_HCLK_Div8);    //内核滴答定时器配置,用于led任务轮循 
	RCC_PeriphClock_Config();
	Led_Init();                                            //led灯初始化 
	Key_Init();
	TIM3_Init(999,71);                                     //定时器3初始化,pwm周期为1KHZ
	
	while(1)
	{
		if(led_pwm_ctr_cnt >= 1)    //500ms轮询一次
 		{
			led_pwm_ctr_cnt = 0;
			if(K1 == 0)                //k1按键被按下
			{
				if(led_pwm < 1000)
					led_pwm++;
				TIM_SetCompare2(TIM3, led_pwm);
				TIM_SetCompare1(TIM3, led_pwm);
			}
			else
			if(K2 == 0)
			{
				if(led_pwm > 0)
					led_pwm--;
				TIM_SetCompare2(TIM3, led_pwm);
				TIM_SetCompare1(TIM3, led_pwm);
			}
		}
	}
}