控制控制每个函数每秒执行次数。
方法1相对方法2更整洁，不用每次在时钟中断里添加新的计数值。减低代码间耦合，非常nice！
方法1：

void __attribute__((interrupt)) _SysTick_exception (void)
{
	SYSTICK_Counter_Updata();   
	SysTick++;
}
//关键函数:计时判断。
uint32_t IsSysTimeout(uint32_t *timer)
{
	if(*timer == 0)
		return 1;
	else if((SysTick - *timer) <= 0x7fffffff)
	{
		*timer = 0;
		return 1;
	}
	else
		return 0;
}
void SetSysTimer(uint32_t *timer,uint32_t TimeParaVal)
{
	*timer = TimeParaVal + SysTick;
	if(*timer == 0)	*timer = 1; //not set timer to 0 for timer is running
}


//main主循环
int main()
{
	uint32_t loop10hz,loop1000hz;
	...
	while(1)
	{
		if(IsSysTimeout(&loop10hz))
		{
			SetSysTimer(&loop10hz,100);
			Demo_LED1_ON_OFF();
		}
		
		if(IsSysTimeout(&loop1000hz))
		{
			SetSysTimer(&loop1000hz,1);
			Demo_LED2_ON_OFF();
		}
	}
}

方法2

void TIM4_IRQHandler(void)		//1ms中断一次
{
    if( TIM_GetITStatus(TIM4 , TIM_IT_Update) != RESET ) 
    {     
					anyCnt++;
					loop200HzCnt++;
					loop100HzCnt++;

					if(++loop50HzCnt * 50 >= (1000))
					{
							loop50HzCnt=0;
							loop50HzFlag=1;
					}
					if(++loop20HzCnt * 20 >=1000 )
					{
							loop20HzCnt=0;
							loop20HzFlag=1;
					}
					if(++loop10HzCnt * 10 >=1000 )
					{
							loop10HzCnt=0;
							loop10HzFlag=1;
					}
          
          TIM_ClearITPendingBit(TIM4 , TIM_FLAG_Update);   //清除中断标志   
    }
}
int main(void)
{
    while (1)
    { 
        if(anyCnt>=5)
        {
            anyCnt=0;
            realExecPrd[0]=micros()-startTime[0];
            startTime[0]=micros();
            ....
            execTime[0]=micros()-startTime[0];	//测量任务执行时间，CPU占用率
        }
		//100Hz Loop
        if(loop100HzCnt>=10)
        {
            loop100HzCnt=0;
            realExecPrd[1]=micros()-startTime[1];
            startTime[1]=micros();
			....
            execTime[1]=micros()-startTime[1];
        }
 
        //50Hz Loop
        if(loop50HzFlag)
        {
            loop50HzFlag=0;
            realExecPrd[3]=micros()-startTime[3];
            startTime[3]=micros();
            ...
            execTime[3]=micros()-startTime[3];
            ...
        }

        //10Hz loop
        if(loop10HzFlag)
        {
            loop10HzFlag=0;
            realExecPrd[2]=micros()-startTime[2];
            startTime[2]=micros();
			....   
			execTime[2]=micros()-startTime[2];  
        }
}