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。

1，开发环境

1，固件库：STM32F4xx_DSP_StdPeriph_Lib_V1.8.0

2，编译器：ARMCCV5.06

3，IDE：KeiluVision5

4，操作系统：Windows10专业版

2，程序源码

MeasureTime.h文件

［cpp］viewplaincopy/**

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

*@fileMeasureTime.h

*@authorXinLi

*@versionv1.0

*@date24-October-2017

*@briefMeasureprogramruntimemodule.

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

*@attention

*

*《h2》《center》Copyright©2017XinLi《/center》《/h2》

*

*Thisprogramisfreesoftware：youcanredistributeitand/ormodify

*itunderthetermsoftheGNUGeneralPublicLicenseaspublishedby

*theFreeSoftwareFoundation，eitherversion3oftheLicense，or

*(atyouroption)anylaterversion.

*

*Thisprogramisdistributedinthehopethatitwillbeuseful，

*butWITHOUTANYWARRANTY;withouteventheimpliedwarrantyof

*MERCHANTABILITYorFITNESSFORAPARTICULARPURPOSE.Seethe

*GNUGeneralPublicLicenseformoredetails.

*

*YoushouldhavereceivedacopyoftheGNUGeneralPublicLicense

*alongwiththisprogram.Ifnot，see《https://www.gnu.org/licenses/》。

*

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

*/

#ifndef__MEASURETIME_H

#define__MEASURETIME_H

#ifdef__cplusplus

extern“C”{

#endif

/*Headerincludes-----------------------------------------------------------*/

#include“stm32f4xx.h”

/*Macrodefinitions---------------------------------------------------------*/

/*Typedefinitions----------------------------------------------------------*/

/*Variabledeclarations-----------------------------------------------------*/

/*Variabledefinitions------------------------------------------------------*/

/*Functiondeclarations-----------------------------------------------------*/

/*Functiondefinitions------------------------------------------------------*/

/**

*@briefStartmeasuretime.

*@paramNone.

*@returnNone.

*/

__STATIC_INLINEvoidMeasureTimeStart(void)

{

SysTick-》CTRL|=SysTick_CLKSource_HCLK;/*SettheSysTickclocksource.*/

SysTick-》LOAD=0xFFFFFF;/*Timeload(SysTick-》LOADis24bit)。*/

SysTick-》VAL=0xFFFFFF;/*Emptythecountervalue.*/

SysTick-》CTRL|=SysTick_CTRL_ENABLE_Msk;/*Startthecountdown.*/

__nop();/*Waitingforamachinecycle.*/

}

/**

*@briefStopmeasuretime.

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

*@returnProgramruntime(unit：us)。

*/

__STATIC_INLINEdoubleMeasureTimeStop(uint32_tclock)

{

uint32_tcount=SysTick-》VAL;/*Readthecountervalue.*/

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

doubletime=0.0;

if(clock》0)

{

time=(double)(0xFFFFFF-count)/(double)clock;/*Calculateprogramruntime.*/

}

returntime;

}

#ifdef__cplusplus

}

#endif

#endif/*__MEASURETIME_H*/

main.c文件

［cpp］viewplaincopy/**

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

*@filemain.c

*@authorXinLi

*@versionv1.0

*@date24-October-2017

*@briefMainprogrambody.

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

*@attention

*

*《h2》《center》Copyright©2017XinLi《/center》《/h2》

*

*Thisprogramisfreesoftware：youcanredistributeitand/ormodify

*itunderthetermsoftheGNUGeneralPublicLicenseaspublishedby

*theFreeSoftwareFoundation，eitherversion3oftheLicense，or

*(atyouroption)anylaterversion.

*

*Thisprogramisdistributedinthehopethatitwillbeuseful，

*butWITHOUTANYWARRANTY;withouteventheimpliedwarrantyof

*MERCHANTABILITYorFITNESSFORAPARTICULARPURPOSE.Seethe

*GNUGeneralPublicLicenseformoredetails.

*

*YoushouldhavereceivedacopyoftheGNUGeneralPublicLicense

*alongwiththisprogram.Ifnot，see《https://www.gnu.org/licenses/》。

*

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

*/

/*Headerincludes-----------------------------------------------------------*/

#include“main.h”

#include“MeasureTime.h”

/*Macrodefinitions---------------------------------------------------------*/

/*Typedefinitions----------------------------------------------------------*/

/*Variabledeclarations-----------------------------------------------------*/

/*Variabledefinitions------------------------------------------------------*/

static__IOdoublerunTime=0.0;

/*Functiondeclarations-----------------------------------------------------*/

__STATIC_INLINEvoiddelay_1us(void);

/*Functiondefinitions------------------------------------------------------*/

/**

*@briefMainprogram.

*@paramNone.

*@returnNone.

*/

intmain(void)

{

for(;;)

{

MeasureTimeStart();

delay_1us();

runTime=MeasureTimeStop(84);

}

}

/**

*@briefOnemicroseconddelay.

*@paramNone.

*@returnNone.

*/

__STATIC_INLINEvoiddelay_1us(void)

{

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

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

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

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

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

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

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

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

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

}