timer.c

LED控制

#include	<pic.h>
#include	"..\inc\include.h"

/***********************************************************************
**  Fosc = 8MHz, CLKO = Fosc/4 = 2MHz
**
***********************************************************************/

volatile uchar   Cnt10us;						//延时10us定时器计数器
volatile uchar   Cnt1ms;						//延时1ms定时器计数器

void Timer_Init(void)
{
	//注意：OPTION复位值为0xFF
	//CLKO = Fosc/4 = 1MHz
//---Timer0---
	OPTION &= ~7;	//PS<2:0> = 0
	//OPTION |= 3;	//PS<2:0> = 3,TMR0 rate = 1:16, 
	//OPTION |= 2;	//PS<2:0> = 2,TMR0 rate = 1:8,
	//OPTION |= 1;	//PS<2:0> = 1,TMR0 rate = 1:4,
	OPTION |= 0;	//PS<2:0> = 0,TMR0 rate = 1:2,
	
	T0CS = 0;		//clock source slecet internal
	PSA = 0;		//Prescaler is assigned to the Timer0 module
	//TMR0 = (256-250);	// 4us*250=1000us(1ms)
	//TMR0 = (256-1);	// 4us*250=1000us(1ms)
	TMR0IE = 0;		//Disable Timer0 interrupt
//---Timer1---
	T1CKPS1 = 0;	//prescale value 1:1
	T1CKPS0 = 0;
	TMR1CS = 0;		//Clock Source Select,0=Internal clock (FOSC/4)
	
	TMR1IF = 0;		//Clear interrupt flag
	TMR1IE = 0;		//Disable Timer1 interrupt

	TMR1ON = 0;		//Disable Timer1
//---Timer2---

}
/***********************************************************************
**  10us延时
***********************************************************************/
void  Delay10us(uchar t)
{
	if(t==0) return;
	Cnt10us = t;
	TMR0 = (256-5);		//(0.5us*2)*5 = 5us	
	TMR0IF = 0;
	TMR0IE = 1;
    
    while(Cnt10us);
	TMR0IE = 0;
}

void Timer0_ISR(void)
{
	TMR0IF = 0;
	if(Cnt10us){
		Cnt10us--;	
	}
	if(Cnt10us){
		TMR0 = (256-5);		//(0.5us*2)*5 = 5us	
	}
}
/***********************************************************************
**  10ms延时
***********************************************************************/
void  Delay1ms(uchar t)
{
	if(t==0) return;
	Cnt1ms = t;
	TMR1H = (65536-2000)/256;	//0.5us*2000 = 1000us(1ms)
	TMR1L = (65536-2000)%256;

	TMR1IF = 0;		//Clear interrupt flag
	TMR1IE = 1;		//Enable Timer1 interrupt
	TMR1ON = 1;		//Enable Timer1
    
    while(Cnt1ms);
	TMR1ON = 0;		//Disable Timer1
	TMR1IE = 0;		//Disable Timer1 interrupt
}

void Timer1_ISR(void)
{
	TMR1IF = 0;
	if(Cnt1ms){
		Cnt1ms--;	
	}
	if(Cnt1ms){
		TMR1H = (65536-2000)/256;	//0.5us*20000 = 10000us(10ms)
		TMR1L = (65536-2000)%256;
	}
}