timer.c

c51串口编程的例子

#include<reg51.h>

#include "tdp.h"

#define TIMER0_COUNT	0xDC11  	/*10000h - ((11059200Hz/(12*FREQ)) - 17 )*/

static xdata unsigned timer0_tick;

/*Timer T0 Interrupt service func*/
static void timer0_isr(void) interrupt 1 using 1 {
	P1 |= 0x80;
	TR0 = 0;								/* Stop T0 */
	TL0 = TL0 + (TIMER0_COUNT & 0x00FF);
	TH0 = TH0 + (TIMER0_COUNT >> 8);
	TR0 = 1;								/* start T0 */
	timer0_tick++;
	P1 &= ~0x80;
}

/* Timer T0 Initialization*/
void timer0_initialize(void) {
	INT_DISABLE;							/* close interrupt */
	timer0_tick = 0;
	TR0 = 0;								/* Stop T0 */
	TMOD &= ~0x0F;							/* set T0 Working Type */
	TMOD |= 0x01;
	TL0 = (TIMER0_COUNT & 0x00FF);
	TH0 = (TIMER0_COUNT >> 8 );
	PT0 = 0;
	ET0 = 1;
	TR0 = 1;
	TR0 = 1;								/* start T0 */
	INT_ENABLE;								/* open Int */
}

/* Timer T0 tick func. */
unsigned timer0_count(void) {
	xdata unsigned t;
	INT_DISABLE;
	t = timer0_tick;
	INT_ENABLE;
	return (t);
}

/* TIMER T0 elapse COunter */
unsigned timer0_elapsed_count (unsigned count) {
	return (timer0_count() - count);
}

/* Timer T0 Waiting */
void timer0_wait(unsigned count) {
	xdata unsigned start_count;
	start_count = timer0_count();
	while (timer0_elapsed_count(start_count) <= count){}
}