滴答定时器

SysTick.h

#ifndef __SysTick_h
#define __SysTick_h
#include "stm32f10x.h"

void SysTick_ms(uint32_t ms);
void SysTick_us(uint32_t us);

#endif

SysTick.c

#include <stdio.h>
#include "SysTick.h"
#include "stm32f10x.h"

void SysTick_ms(uint32_t ms)
{
    SysTick->CTRL = 0x00;                   //控制及状态寄存器复位
    SysTick->LOAD = 9000 * ms;          //滴答延时
    SysTick->VAL = 0;                           //当前寄存器为0
    SysTick->CTRL |= 0x01;                  //打开
    while((SysTick->CTRL & 0x10000) == 0);  //读取寄存器位时，跳出循环
    SysTick->CTRL &= 0xfffe;                //复位
}

void SysTick_us(uint32_t us)
{
    SysTick->CTRL = 0x00;                   
    SysTick->LOAD = 9 * us;                
    SysTick->VAL = 0;                                               
    SysTick->CTRL |= 0x01;                                  
    while((SysTick->CTRL & 0x10000) == 0); 
    SysTick->CTRL &= 0xfffe;   
}