在實際的項目開發(fā)過程中，常常遇到需要得到一段代碼的運行時間，通常的方法是用示波器來測量，這篇博文將用SysTick來實現(xiàn)精確測量程序運行的時間。STM32F4的內(nèi)核定時器SysTick是一個24位的定時器，需要注意最大的測量時間。

1，開發(fā)環(huán)境

1，固件庫：STM32F4xx_DSP_StdPeriph_Lib_V1.8.0

2，編譯器：ARMCC V5.06

3，IDE：Keil uVision5

4，操作系統(tǒng)：Windows 10 專業(yè)版

2，程序源碼

MeasureTime.h文件

1. /**

2. ******************************************************************************

3. *@fileMeasureTime.h

4. *@authorXinLi

5. *@versionv1.0

6. *@date24-October-2017

7. *@briefMeasureprogramruntimemodule.

8. ******************************************************************************

9. *@attention

10. *

11. *

    Copyright©2017XinLi

12. *

13. *Thisprogramisfreesoftware:youcanredistributeitand/ormodify

14. *itunderthetermsoftheGNUGeneralPublicLicenseaspublishedby

15. *theFreeSoftwareFoundation,eitherversion3oftheLicense,or

16. *(atyouroption)anylaterversion.

17. *

18. *Thisprogramisdistributedinthehopethatitwillbeuseful,

19. *butWITHOUTANYWARRANTY;withouteventheimpliedwarrantyof

20. *MERCHANTABILITYorFITNESSFORAPARTICULARPURPOSE.Seethe

21. *GNUGeneralPublicLicenseformoredetails.

22. *

23. *YoushouldhavereceivedacopyoftheGNUGeneralPublicLicense

24. *alongwiththisprogram.Ifnot,see.

25. *

26. ******************************************************************************

27. */

29. #ifndef__MEASURETIME_H

30. #define__MEASURETIME_H

32. #ifdef__cplusplus

33. extern"C"{

34. #endif

36. /*Headerincludes-----------------------------------------------------------*/

37. #include"stm32f4xx.h"

39. /*Macrodefinitions---------------------------------------------------------*/

40. /*Typedefinitions----------------------------------------------------------*/

41. /*Variabledeclarations-----------------------------------------------------*/

42. /*Variabledefinitions------------------------------------------------------*/

43. /*Functiondeclarations-----------------------------------------------------*/

44. /*Functiondefinitions------------------------------------------------------*/

46. /**

47. *@briefStartmeasuretime.

48. *@paramNone.

49. *@returnNone.

50. */

51. __STATIC_INLINEvoidMeasureTimeStart(void)

52. {

53. SysTick->CTRL|=SysTick_CLKSource_HCLK;/*SettheSysTickclocksource.*/

54. SysTick->LOAD=0xFFFFFF;/*Timeload(SysTick->LOADis24bit).*/

55. SysTick->VAL=0xFFFFFF;/*Emptythecountervalue.*/

56. SysTick->CTRL|=SysTick_CTRL_ENABLE_Msk;/*Startthecountdown.*/

57. __nop();/*Waitingforamachinecycle.*/

58. }

60. /**

61. *@briefStopmeasuretime.

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

63. *@returnProgramruntime(unit:us).

64. */

65. __STATIC_INLINEdoubleMeasureTimeStop(uint32_tclock)

66. {

67. uint32_tcount=SysTick->VAL;/*Readthecountervalue.*/

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

70. doubletime=0.0;

72. if(clock>0)

73. {

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

75. }

77. returntime;

78. }

80. #ifdef__cplusplus

81. }

82. #endif

84. #endif/*__MEASURETIME_H*/

main.c文件

1. /**

2. ******************************************************************************

3. *@filemain.c

4. *@authorXinLi

5. *@versionv1.0

6. *@date24-October-2017

7. *@briefMainprogrambody.

8. ******************************************************************************

9. *@attention

10. *

11. *

    Copyright©2017XinLi

12. *

13. *Thisprogramisfreesoftware:youcanredistributeitand/ormodify

14. *itunderthetermsoftheGNUGeneralPublicLicenseaspublishedby

15. *theFreeSoftwareFoundation,eitherversion3oftheLicense,or

16. *(atyouroption)anylaterversion.

17. *

18. *Thisprogramisdistributedinthehopethatitwillbeuseful,

19. *butWITHOUTANYWARRANTY;withouteventheimpliedwarrantyof

20. *MERCHANTABILITYorFITNESSFORAPARTICULARPURPOSE.Seethe

21. *GNUGeneralPublicLicenseformoredetails.

22. *

23. *YoushouldhavereceivedacopyoftheGNUGeneralPublicLicense

24. *alongwiththisprogram.Ifnot,see.

25. *

26. ******************************************************************************

27. */

29. /*Headerincludes-----------------------------------------------------------*/

30. #include"main.h"

31. #include"MeasureTime.h"

33. /*Macrodefinitions---------------------------------------------------------*/

34. /*Typedefinitions----------------------------------------------------------*/

35. /*Variabledeclarations-----------------------------------------------------*/

36. /*Variabledefinitions------------------------------------------------------*/

37. static__IOdoublerunTime=0.0;

39. /*Functiondeclarations-----------------------------------------------------*/

40. __STATIC_INLINEvoiddelay_1us(void);

42. /*Functiondefinitions------------------------------------------------------*/

44. /**

45. *@briefMainprogram.

46. *@paramNone.

47. *@returnNone.

48. */