如何用SysTick实现测量程序运行时间

算法&编程学院 2018-05-09 5933

描述

在实际的项目开发过程中，常常遇到需要得到一段代码的运行时间，通常的方法是用示波器来测量，这篇博文将用SysTick来实现精确测量程序运行的时间。STM32F4的内核定时器SysTick是一个24位的定时器，需要注意最大的测量时间。

Systick

1，开发环境

1，固件库：STM32F4xx_DSP_StdPeriph_Lib_V1.8.0

2，编译器：ARMCC V5.06

3，IDE：Keil uVision5

4，操作系统：Windows 10 专业版

2，程序源码

MeasureTime.h文件

［cpp］ view plain copy/**

******************************************************************************

* @file MeasureTime.h

* @author XinLi

* @version v1.0

* @date 24-October-2017

* @brief Measure program run time module.

******************************************************************************

* @attention

* This program is free software： you can redistribute it and/or modify

* it under the terms of the GNU General Public License as published by

* the Free Software Foundation， either version 3 of the License， or

* （at your option） any later version.

* This program is distributed in the hope that it will be useful，

* but WITHOUT ANY WARRANTY; without even the implied warranty of

* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the

* GNU General Public License for more details.

* You should have received a copy of the GNU General Public License

* along with this program. If not， see 《https://www.gnu.org/licenses/》。

******************************************************************************

#ifndef __MEASURETIME_H

#define __MEASURETIME_H

#ifdef __cplusplus

extern “C” {

#endif

/* Header includes -----------------------------------------------------------*/

#include “stm32f4xx.h”

/* Macro definitions ---------------------------------------------------------*/

/* Type definitions ----------------------------------------------------------*/

/* Variable declarations -----------------------------------------------------*/

/* Variable definitions ------------------------------------------------------*/

/* Function declarations -----------------------------------------------------*/

/* Function definitions ------------------------------------------------------*/

/**

* @brief Start measure time.

* @param None.

* @return None.

__STATIC_INLINE void MeasureTimeStart（void）

{

SysTick-》CTRL |= SysTick_CLKSource_HCLK; /* Set the SysTick clock source. */

SysTick-》LOAD = 0xFFFFFF; /* Time load （SysTick-》 LOAD is 24bit）。 */

SysTick-》VAL = 0xFFFFFF; /* Empty the counter value. */

SysTick-》CTRL |= SysTick_CTRL_ENABLE_Msk; /* Start the countdown. */

__nop（）; /* Waiting for a machine cycle. */

}

/**

* @brief Stop measure time.

* @param ［in］ clock： System clock frequency（unit： MHz）。

* @return Program run time（unit： us）。

__STATIC_INLINE double MeasureTimeStop（uint32_t clock）

{

uint32_t count = SysTick-》VAL; /* Read the counter value. */

SysTick-》CTRL &= ~SysTick_CTRL_ENABLE_Msk; /* Close counter. */

double time = 0.0;

if（clock 》 0）

{

time = （double）（0xFFFFFF - count） / （double）clock; /* Calculate program run time. */

}

return time;

}

#ifdef __cplusplus

}

#endif

#endif /* __MEASURETIME_H */

main.c文件

［cpp］ view plain copy/**

******************************************************************************

* @file main.c

* @author XinLi

* @version v1.0

* @date 24-October-2017

* @brief Main program body.

******************************************************************************

* @attention

* This program is free software： you can redistribute it and/or modify

* it under the terms of the GNU General Public License as published by

* the Free Software Foundation， either version 3 of the License， or

* （at your option） any later version.

* This program is distributed in the hope that it will be useful，

* but WITHOUT ANY WARRANTY; without even the implied warranty of

* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the

* GNU General Public License for more details.

* You should have received a copy of the GNU General Public License

* along with this program. If not， see 《https://www.gnu.org/licenses/》。

******************************************************************************

/* Header includes -----------------------------------------------------------*/

#include “main.h”

#include “MeasureTime.h”

/* Macro definitions ---------------------------------------------------------*/

/* Type definitions ----------------------------------------------------------*/

/* Variable declarations -----------------------------------------------------*/

/* Variable definitions ------------------------------------------------------*/

static __IO double runTime = 0.0;

/* Function declarations -----------------------------------------------------*/

__STATIC_INLINE void delay_1us（void）;

/* Function definitions ------------------------------------------------------*/

/**

* @brief Main program.

* @param None.

* @return None.

int main（void）

{

for（;;）

{

MeasureTimeStart（）;

delay_1us（）;

runTime = MeasureTimeStop（84）;

}

/**

* @brief One microsecond delay.

* @param None.

* @return None.

__STATIC_INLINE void delay_1us（void）

{

__nop（）; __nop（）; __nop（）; __nop（）; __nop（）; __nop（）; __nop（）; __nop（）; __nop（）; __nop（）;

__nop（）; __nop（）; __nop（）; __nop（）;

}

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