C51控制并口打印机实例：
/* 沈阳新荣达电子 */
/* 2004-12-7 */
#include <reg52.h>
#define uchar unsigned char
#define uint unsigned int
#define data_8 P0
sbit BUSY = P1^2; //打印机 BUSY 接P1.2
sbit STB = P1^0; //打印机 STB 接P1.0
void print(uchar j) //打印子程序
{ uchar i;
while(BUSY){}; //BUSY=1，打印机忙，等待BUSY 为0 再发数
data_8=j;
STB=0;
i++;
i--;
STB=1; //给出数据锁存时钟
BUSY=1;
}
void main(void)
{BUSY = 1; //忙信号置高
STB = 1; //选通信号置高
print(0x1b); //打印机初始化命令
print(0x38);
print(0x04);
for(;;)
{
print(0xd0); //发送汉字内码“新荣达”
print(0xc2);
print(0xc8);
print(0xd9);
print(0xb4);
print(0xef);
print(0x0d); //换行
}
}
