/*******************************************************************************
* Function Name : DS18B20_Delay
* Description : 精确延时us,参数范围0~1000.利用SysTick延时
* Input : 延时时间
* Output : None
* Return : None
*******************************************************************************/
void OWDelay(unsigned int t)
{
unsigned int start,total,diff = 0;
unsigned int count = 0;
unsigned int temp;
#if OS_CRITICAL_METHOD == 3
OS_CPU_SR cpu_sr = 0;
#endif
temp = 10000*SYSCLK_1US;
OS_ENTER_CRITICAL();
start = SysTick_GetCounter();
total = t*SYSCLK_1US;
while(diff < total)
{
count = SysTick_GetCounter();
if(start < count)
{
diff = temp - (count - start);
}
else
{
diff = start -count;
}
}
OS_EXIT_CRITICAL();
}
void stop() { enabled = 0; us_counter_end = SysTick_GetCounter(); }
void start() { us_counter = SysTick_GetCounter(); enabled = 1; }