#include <AT89X51.H>
#include <stdio.h>

void main(void)
{
	unsigned int I = 1;
	unsigned int SUM = 0; //設初值

	SCON = 0x50; //串口方式1,允許接收
	TMOD = 0x20; //定時器1定時方式2
	TCON = 0x40; //設定時器1開始計數
	TH1 = 0xE8;	//11.0592MHz 1200波特率
	TL1 = 0xE8;
	TI = 1;
	TR1 = 1; //啟動定時器
	
	while(I<=10)
		{
			SUM = I + SUM; //累加
			printf ("%d SUM=%d\n",I,SUM); //顯示
			I++;
		}
	while(1); //這句是為了不讓程序完后，程序指針繼續向下造成程序“跑飛”
}
//最后運行結果是SUM=55;