新手求教，关于systick中的timingdelay变量

如下一段代码

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static __IO uint32_t TimingDelay;



void Delay(__IO uint32_t nTime);

void TimingDelay_Decrement(void);



int main(void)

{



//初始化略去



/* Setup SysTick Timer for 1 msec interrupts */

if (SysTick_Config(SystemFrequency / 1000))

{ 

/* Capture error */ 

while (1);

}



while (1)

{

GPIO_SetBits(GPIOC, GPIO_Pin_6); 



Delay(500); //ms



GPIO_ResetBits(GPIOC, GPIO_Pin_6); 



Delay(500);

}

}





void TimingDelay_Decrement(void)

{

if (TimingDelay != 0x00)

{ 

TimingDelay--;

}

}





void Delay(__IO uint32_t nTime)

{ 

TimingDelay = nTime;



while(TimingDelay != 0);

}

为什么TimingDelay能被自减，用keil仿真就死在void Delay（）里了
下载下去运行就没问题
搞不懂

找到了

复制

void SysTick_Handler(void)

{

TimingDelay_Decrement();

}