V0.41 电调定时器程序中,延时是怎么回事?请教高人解救。。。
V0.41 电调定时器程序中,延时是怎么回事?请教高人解救。。。#include "main.h"
volatile unsigned int CountMilliseconds = 0;//毫秒计数
volatile unsigned char Timer0Overflow;
enum {
STOP = 0,
CK = 1,
CK8 = 2,
CK64 = 3,
CK256 = 4,
CK1024 = 5,
T0_FALLING_EDGE= 6,
T0_RISING_EDGE = 7
};
SIGNAL(SIG_OVERFLOW0)
{
static unsigned char cnt;
Timer0Overflow++;
if(!cnt--)
{
cnt = 3;
CountMilliseconds += 1;
if(I2C_Timeout) I2C_Timeout--;
if(PPM_Timeout) PPM_Timeout--; else anz_ppm_werte = 0;
if(SIO_Timeout) SIO_Timeout--;
}
}
void Timer0_Init(void)
{
TCCR0= TIMER_TEILER;
// TCNT0 = -TIMER_RELOAD_VALUE;// reload
TIM0_START;
TIMER2_INT_ENABLE;
}
unsigned int SetDelay(unsigned int t)
{
return(CountMilliseconds + t - 1);
}
char CheckDelay (unsigned int t)
{
return(((t - CountMilliseconds) & 0x8000) >> 8); 这部分起到什么作用?
}
void Delay_ms(unsigned int w)
{
unsigned int akt;
akt = SetDelay(w);
while (!CheckDelay(akt)); 这又是说明了什么呢?
} 同问,希望高手能指点 char CheckDelay (unsigned int t)
{
return(((t - CountMilliseconds) & 0x8000) >> 8); 这部分起到什么作用?
}
//这里最高为变成1的时候,就说明时间到了。正数的最高为为0,复苏最高位为1.
void Delay_ms(unsigned int w)
{
unsigned int akt;
akt = SetDelay(w);
while (!CheckDelay(akt)); 这又是说明了什么呢?
}
//也简单就是 卡 while, 等在 时间的过去!
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