[嵌入式]STM32F103 用SysTick写延时函数范例代码

#ifndef _BSP_SYSTICK_H
#define _BSP_SYSTICK_H

#include "stm32f10x.h"
#include "core_cm3.h"

void SysTick_Dalay_us(uint32_t us);
void SysTick_Dalay_ms(uint32_t ms);
#endif /* _BSP_SYSTICK_H */

#include "bsp_systick.h"

static __INLINE uint32_t _SysTick_Config(uint32_t ticks)
{ 
  if (ticks > SysTick_LOAD_RELOAD_Msk)  return (1);            /* Reload value impossible */
                                                               
  SysTick->LOAD  = (ticks & SysTick_LOAD_RELOAD_Msk) - 1;      /* set reload register */
  NVIC_SetPriority (SysTick_IRQn, (1<<__NVIC_PRIO_BITS) - 1);  /* set Priority for Cortex-M0 System Interrupts */
  SysTick->VAL   = 0;                                          /* Load the SysTick Counter Value */
  SysTick->CTRL  = SysTick_CTRL_CLKSOURCE_Msk | 
                   SysTick_CTRL_TICKINT_Msk   | 
                   SysTick_CTRL_ENABLE_Msk;                    /* Enable SysTick IRQ and SysTick Timer */
  return (0);                                                  /* Function successful */
}

void SysTick_Dalay_us(uint32_t us)
{
	int i;
	_SysTick_Config(72);
	for(i=0;i<us;i++){
		while(!(SysTick->CTRL & (1<<16)));
	}
	SysTick->CTRL &= ~SysTick_CTRL_ENABLE_Msk;
}

void SysTick_Dalay_ms(uint32_t ms)
{
	int i;
	_SysTick_Config(72000);
	for(i=0;i<ms;i++){
		while(!(SysTick->CTRL & (1<<16)));
	}
	SysTick->CTRL &= ~SysTick_CTRL_ENABLE_Msk;
}