STM32F030R8 SYSTICK延时函数时间不对

秋夜月汐 · 发表于 2015-9-15 19:28:24

delay.c文件

#include <delay.h>
static unsigned char fac_us=0;
static unsigned char fac_ms=0;

void delay_init()
{
   SysTick_CLKSourceConfig(SysTick_CLKSource_HCLK_Div8); //?????????±?? HCLK/8
   fac_us=SystemCoreClock/8000000;                                       //???????±????1/8
   fac_ms=(unsigned int)fac_us*1000;
}

void delay_us(int nus)
{
   unsigned int temp;
   SysTick->LOAD=nus*fac_us; //?±??????
   SysTick->VAL=0x00;        //?????????÷
   SysTick->CTRL|=SysTick_CTRL_ENABLE_Msk ;          //????????
   do
   {
       temp=SysTick->CTRL;
   }
   while(temp&0x01&&!(temp&(1<<16)));//?????±??????
   SysTick->CTRL&=~SysTick_CTRL_ENABLE_Msk;       //??±??????÷
   SysTick->VAL =0X00;       //?????????÷
}

void delay_ms(int nms)
{
   unsigned int temp;
   SysTick->LOAD=(unsigned int)nms*fac_ms;//?±??????(SysTick->LOAD??24bit)
   SysTick->VAL =0x00;           //?????????÷
   SysTick->CTRL|=SysTick_CTRL_ENABLE_Msk ;          //????????
   do
   {
       temp=SysTick->CTRL;
   }
   while(temp&0x01&&!(temp&(1<<16)));//?????±??????
   SysTick->CTRL&=~SysTick_CTRL_ENABLE_Msk;       //??±??????÷
   SysTick->VAL =0X00;       //?????????÷
}

main.c文件

#include <stm32f0xx.h>
#include <led.h>
#include <delay.h>

int main()
{

   delay_init();
   LED_Init();
   while(1)
   {
       GPIO_SetBits(GPIOA,GPIO_Pin_5);
       delay_ms(1000);
       GPIO_ResetBits(GPIOA,GPIO_Pin_5);
       delay_ms(1000);
   }
}

然后板子上的LED闪的飞快.....
求大神帮我看看哪里出问题了