The clock configuration about SysTick

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satellite
Posts: 1
Joined: Wed May 24, 2017 9:11 am

The clock configuration about SysTick

Post by satellite » Wed May 24, 2017 9:19 am

Good afternoon, I want to ask a question about STM32F051. The clock source of systick is 8 frequency division of HCLK and this is the datasheet of STM32F051: http://www.kynix.com/uploadfiles/pdf879 ... 51C4T6.pdf .
The code about my systick.c is given below:
[code]#include "Systick.h"

static __IO uint32_t TimingDelay;

void Delay_ms(__IO uint32_t nTime)

  TimingDelay = (nTime*1000);

  while(TimingDelay != 0);
}

void Delay_us(__IO uint32_t nTime)

  TimingDelay = nTime;

  while(TimingDelay != 0);
}

/**
  * @brief  Decrements the TimingDelay variable.
  * @param  None
  * @retval None
  */
void TimingDelay_Decrement(void)
{
  if (TimingDelay != 0x00)
  { 
    TimingDelay--;
  }
}

void Systick_Init(void)
{
  if (SysTick_Config(SystemCoreClock / 1000000))                //1us
  { 
    /* Capture error */ 
    while (1);
  }
}[/code]
And then invoking them in main:
[code] LED_Open();
                        Delay_us(500000);
                        LED_Close();
                        Delay_us(500000);[/code]
When in the file--it.c:
[code]void SysTick_Handler(void)
{
        TimingDelay_Decrement();
}[/code]
Then the light can’t flash. Here the default is set to be frequency division.
2)It can operate normally before. The code is :
[code]void Systick_Init(void)
{
  if (SysTick_Config(SystemCoreClock / 1000))                //1ms
  {
    /* Capture error */
    while (1);
  }
}[/code]
But when invoking them:
  [code] LED_Open();
                        Delay_ms(500);
                        LED_Close();
                        Delay_ms(500);[/code]
The SystemCoreClock is set to be: “uint32_t SystemCoreClock    = 48000000” and it haven’t be changed.
In this situation it is normal, why? ? ?
Last edited by satellite on Thu May 25, 2017 1:33 am, edited 1 time in total.

User avatar
dhylands
Posts: 2712
Joined: Mon Jan 06, 2014 6:08 pm
Location: Shuswap, BC, Canada
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Re: The clock configuration about SysTick

Post by dhylands » Wed May 24, 2017 5:19 pm

Are you porting MicroPyhon to the STM32F051?

If not, then this is definitely the wrong place to be asking about this. I'd recommend that you try the st forums instead.

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