#pragma db oe sb 
#include<reg51.h>
#define uchar unsigned char

sbit STB=P3^5;
sbit BUSY=P3^3;

uchar code line[]= 
    {0x57,0x45,0x4c,0x43,0x4f,0x4d,0x45}; /* 預(yù)定義字符信息"WELCOME" */

void prnchar(uchar x) {      /* 字符打印函數(shù) */
   P1=x;                     /* 輸出一個ASCII字符 */
   STB=0;                    /* 產(chǎn)生STROBE低電平 */
   STB=1;                    /* 產(chǎn)生STROBE上升沿 */
   while(BUSY);              /* 查詢等待PP40打印結(jié)束 */
}

void prnline(void) {         /* 行打印函數(shù) */
  uchar i;
   for (i=0;i<=6;i++) {      /* 打印輸出一行預(yù)定義信息 */
       P1=line[i];
       STB=0;
       STB=1;
       while(BUSY);
   }
}

void main(void) {
   prnline();                /* 打印輸出"WELCOME" */
   prnchar(0x0D);            /* 換行 */
   prnchar(0x31);            /* 打印輸出"1997" */
   prnchar(0x39);
   prnchar(0x39);
   prnchar(0x37);
 }