STM32F4 (Using SysTick to accurately measure the program running time)

In the actual project development process, we often need to get the running time of a section of code. The usual method is to use an oscilloscope to measure it. This blog post will use SysTick to accurately measure the program running time. The core timer SysTick of STM32F4 is a 24-bit timer, and you need to pay attention to the maximum measurement time.

1. Development Environment

      1. Firmware library: STM32F4xx_DSP_StdPeriph_Lib_V1.8.0

      2. Compiler: ARMCC V5.06

      3. IDE: Keil uVision5

      4. Operating system: Windows 10 Professional

2. Program source code

      MeasureTime.h file

1. /** 

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

3.   * @file MeasureTime.h 

4.   * @author XinLi 

5.   * @version v1.0 

6.   * @date 24-October-2017 

7.   * @brief Measure program run time module. 

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

9.   * @attention 

10.   * 

11.   *

    Copyright © 2017 XinLi

     

12.   * 

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

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

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

16.   * (at your option) any later version. 

17.   * 

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

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

20.   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 

21.   * GNU General Public License for more details. 

22.   * 

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

24.   * along with this program. If not, see . 

25.   * 

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

27.   */  

28.   

29. #ifndef __MEASURETIME_H  

30. #define __MEASURETIME_H  

31.   

32. #ifdef __cplusplus  

33. extern "C" {  

34. #endif  

35.   

36. /* Header includes ----------------------------------------------- -------------*/  

37. #include "stm32f4xx.h"  

38.   

39. /* Macro definitions -------------------------------------------------- -----------*/  

40. /* Type definitions ----------------------------------------------- ----------*/  

41. /* Variable declarations ----------------------------------------------- -------*/  

42. /* Variable definitions -------------------------------------------------- --------*/  

43. /* Function declarations ----------------------------------------------- -------*/  

44. /* Function definitions ----------------------------------------------- --------*/  

45.   

46. /** 

47.   * @brief Start measure time. 

48.   * @param None. 

49.   * @return None. 

50.   */  

51. __STATIC_INLINE void MeasureTimeStart(void)  

52. {  

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

54.   SysTick->LOAD = 0xFFFFFF; /* Time load (SysTick-> LOAD is 24bit). */  

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

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

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

58. }  

59.   

60. /** 

61.   * @brief Stop measuring time. 

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

63.   * @return Program run time(unit: us). 

64.   */  

65. __STATIC_INLINE double MeasureTimeStop(uint32_t clock)  

66. {  

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

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

69.     

70.   double time = 0.0;  

71.     

72.   if(clock > 0)  

73.   {  

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

75.   }  

76.     

77.   return time;  

78. }  

79.   

80. #ifdef __cplusplus  

81. }  

82. #endif  

83.   

84. #endif /* __MEASURETIME_H */  

      main.c file

1. /** 

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

3.   * @file main.c 

4.   * @author XinLi 

5.   * @version v1.0 

6.   * @date 24-October-2017 

7.   * @brief Main program body. 

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

9.   * @attention 

10.   * 

11.   *

    Copyright © 2017 XinLi

     

12.   * 

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

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

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

16.   * (at your option) any later version. 

17.   * 

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

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

20.   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 

21.   * GNU General Public License for more details. 

22.   * 

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

24.   * along with this program. If not, see . 

25.   * 

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

27.   */  

28.   

29. /* Header includes ----------------------------------------------- -------------*/  

30. #include "main.h"  

31. #include "MeasureTime.h"  

32.   

33. /* Macro definitions -------------------------------------------------- -----------*/  

34. /* Type definitions ----------------------------------------------- ----------*/  

35. /* Variable declarations ----------------------------------------------- -------*/  

36. /* Variable definitions -------------------------------------------------- --------*/  

37. static __IO double runTime = 0.0;  

38.   

39. /* Function declarations ----------------------------------------------- -------*/  

40. __STATIC_INLINE void delay_1us(void);  

41.   

42. /* Function definitions ----------------------------------------------- --------*/  

43.   

44. /** 

45.   * @brief Main program. 

46.   * @param None. 

47.   * @return None. 

48.   */  

49. int main(void)  

50. {  

51.   for(;;)  

52.   {  

53.     MeasureTimeStart();  

54.     delay_1us();  

55.     runTime = MeasureTimeStop(84);  

56.   }  

57. }  

58.   

59. /** 

60.   * @brief One microsecond delay. 

61.   * @param None. 

62.   * @return None. 

63.   */  

64. __STATIC_INLINE void delay_1us(void)  

65. {  

66.   __nop(); __nop(); __nop(); __nop(); __nop(); __nop(); __nop(); __nop(); __nop(); __nop();  

67.   __nop(); __nop(); __nop(); __nop(); __nop(); __nop(); __nop(); __nop(); __nop(); __nop();  

68.   __nop(); __nop(); __nop(); __nop(); __nop(); __nop(); __nop(); __nop(); __nop(); __nop();  

69.   __nop(); __nop(); __nop(); __nop(); __nop(); __nop(); __nop(); __nop(); __nop(); __nop();  

70.   __nop(); __nop(); __nop(); __nop(); __nop(); __nop(); __nop(); __nop(); __nop(); __nop();  

71.   __nop(); __nop(); __nop(); __nop(); __nop(); __nop(); __nop(); __nop(); __nop(); __nop();  

72.   __nop(); __nop(); __nop(); __nop(); __nop(); __nop(); __nop(); __nop(); __nop(); __nop();  

73.   __nop(); __nop(); __nop(); __nop(); __nop(); __nop(); __nop(); __nop(); __nop(); __nop();  

74.   __nop(); __nop(); __nop(); __nop();  

75. }