#include "tdp.h"
#include <reg51.h>
#define TIMER0_COUNT	 0xDC11	 /* 10000h-((11059200Hz/(12*FREQ))-17) */

static xdata unsigned timer0_tick;

/* 定時器T0中斷服務函數 */
static void timer0_isr (void) interrupt 1 using 1  {
		P1 |= 0x80;
		TR0 = 0;				    /* 停止 T0 */
		TL0 = TL0 + (TIMER0_COUNT & 0x00FF);
		TH0 = TH0 + (TIMER0_COUNT >> 8);
		TR0 = 1;		     		/* 啟動T0 */		
		timer0_tick++;		
		P1 &= ~0x80;
	}

/* 定時器T0初始化函數 */
void timer0_initialize (void) {
	INT_DISABLE;			/* 關中斷 */	
	timer0_tick = 0;
	TR0 = 0;			    /* 停止T0 */	
	TMOD &= ~0x0F;		/* 設置T0工作方式 */
	TMOD |= 0x01;			
	TL0 = (TIMER0_COUNT & 0x00FF);
	TH0 = (TIMER0_COUNT >> 8);	
	PT0 = 0;				/* 設置T0中斷優先級 */
	ET0 = 1;				/* 允許T0中斷 */	
	TR0 = 1;				/* 啟動T0 */	
	INT_ENABLE;			/* 開中斷 */
}

/* 定時器T0節拍函數 */
unsigned timer0_count (void) {
	xdata unsigned t;
	INT_DISABLE;
	t = timer0_tick;
	INT_ENABLE;	
	return (t);
}

/* 定時器T0節拍計數函數 */
unsigned timer0_elapsed_count (unsigned count) {
	return (timer0_count () - count);
}

/*  定時器T0延時函數  */
void timer0_wait (unsigned count) {
	xdata unsigned start_count;
	start_count = timer0_count ();	
	while (timer0_elapsed_count (start_count) <= count)
	  {
	  }
}