STM32定时器时间的计算方法

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TM32中的定时器有很多用法:

(一)系统时钟(SysTick)

设置非常简单,以下是产生1ms中断的设置,和产生10ms延时的函数:

void RCC_Configuration(void){RCC_ClocksTypeDef RCC_ClockFreq;SystemInit();//源自system_stm32f10x.c文件,只需要调用此函数,则可完成RCC的配置.RCC_GetClocksFreq(&RCC_ClockFreq);

//SYSTICK分频–1ms的系统时钟中断if (SysTick_Config(SystemFrequency / 1000)){while (1); // Capture error}}

void SysTick_Handler(void)//在中断处理函数中的程序{while(tim){tim–;}}

//调用程序:Delay_Ms(10);

当然,前提是要设置好,变量tim要设置成volatile类型的。

(二)第二种涉及到定时器计数时间(TIMx)

TIM_TimeBaseStructure.TIM_Prescaler = 2;//预分频(时钟分频)72M/(2+1)=24MTIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;//向上计数TIM_TimeBaseStructure.TIM_Period = 65535; //装载值18k/144=125hzTIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1;TIM_TimeBaseStructure.TIM_RepetitionCounter = 0x0;TIM_TimeBaseInit(TIM3,&TIM_TimeBaseStructure);

定时时间计算:TIM_TimeBaseStructure.TIM_Prescaler = 2;//分频2 72M/(2+1)/2=24MHzTIM_TimeBaseStructure.TIM_Period = 65535; //计数值65535((1+TIM_Prescaler)/72M)*(1+TIM_Period )=((1+2)/72M)*(1+65535)=0.00273秒=366.2Hz*/

注意两点(来自大虾网,未经检验)(1)TIMx(1-8),在库设置默认的情况下,都是72M的时钟;(2)TIM_TimeBaseStructure.TIM_RepetitionCounter=0;是重复计数,就是重复溢出多少次才给你来一个溢出中断,它对应的寄存器叫TIM1 RCR.如果这个值不配置,上电的时候寄存器值可是随机的,本来1秒中断一次,可能变成N秒中断一次,让你超级头大!

假设系统时钟是72Mhz,TIM1是由PCLK2(72MHz)得到,TIM2-7是由PCLK1得到

关键是设定时钟预分频数,,自动重装载寄存器周期的值

定时器的基本设置

1、 TIM_TimeBaseStructure.TIM_Prescaler = 7199;//时钟预分频数 例如:时

钟频率=72/(时钟预分频+1)

2、TIM_TimeBaseStructure.TIM_Period = 9999; //自动重装载寄存器周期的值(定时

时间) 累计0xFFFF个频率后产生个更新或者中断(也是说定时时间到)

3、 TIM_TimeBaseStructure.TIM_CounterMode = TIM1_CounterMode_Up;//定时器

模式 向上计数

4、TIM_TimeBaseStructure.TIM_ClockDivision = 0x0; //时间分割值

5、TIM_TimeBaseInit(TIM2,&TIM_TimeBaseStructure);//初始化定时器2

6、TIM_ITConfig(TIM2, TIM_IT_Update, ENABLE); //打开中断 溢出中断

7、TIM_Cmd(TIM2, ENABLE);//打开定时器

或者:

TIM_TimeBaseStructure.TIM_Prescaler = 35999;//分频35999 72M/

(35999+1)/2=1Hz 1秒中断溢出一次

TIM_TimeBaseStructure.TIM_Period = 2000; //计数值2000

((1+TIM_Prescaler )/72M)*(1+TIM_Period)=((1+35999)/72M)*(1+2000)=1秒*/

STM32通用定时器的基本定时器功能实现灯闪烁

#include "stm32f10x.h"#include "misc.h"

void RCC_Configuration(void);void NVIC_Configuration(void);void GPIO_Configuration(void);void TIM3_Configuration(void);

int main(void){RCC_Configuration();NVIC_Configuration();GPIO_Configuration();TIM3_Configuration();

TIM_ClearFlag(TIM3, TIM_FLAG_Update);TIM_ARRPreloadConfig(TIM3, DISABLE);

TIM_ITConfig(TIM3, TIM_IT_Update, ENABLE);TIM_Cmd(TIM3, ENABLE);while (1) {;}}void TIM3_Configuration(void){

TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;TIM_TimeBaseStructure.TIM_Period = 9999;TIM_TimeBaseStructure.TIM_Prescaler = 7199;TIM_TimeBaseStructure.TIM_ClockDivision = 0;TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;TIM_TimeBaseInit(TIM3,&TIM_TimeBaseStructure);}void RCC_Configuration(void){SystemInit();RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE);RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOC, ENABLE);

}

void NVIC_Configuration(void){NVIC_InitTypeDef NVIC_InitStructure;NVIC_InitStructure.NVIC_IRQChannel = TIM3_IRQn;NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;NVIC_Init(&NVIC_InitStructure);}void GPIO_Configuration(void){GPIO_InitTypeDef GPIO_InitStructure;GPIO_InitStructure.GPIO_Pin = GPIO_Pin_7;GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;GPIO_Init(GPIOC, &GPIO_InitStructure);

}

#include "stm32f10x_it.h"

把艰辛的劳作看作是生命的必然,

STM32定时器时间的计算方法

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