南昌航空大学单片机之间RS-232串行通信的实现(5)

case 2: keyno = 1;break; case 4: keyno = 2;break; case 8: keyno = 3;break;

default: keyno = 16; //无键按下 }

//低四位置1，放入4列 KEY = 0xf0; delay(1); //

i = KEY >> 4 ^ 0x0f; //对0-3行分别附件起始值 switch(i) {

case 1: keyno += 0;break; case 2: keyno += 4;break; case 4: keyno += 8;break; case 8: keyno += 12;break; }

delay(100); }

2.从机程序清单

#include //包含头文件 unsigned char temp; unsigned char flag = 'n'; #define DIG P1

void delay(unsigned int x) {

unsigned char i;

17

while(x--) {

for(i = 0;i < 120;i++); } }

void explanation(unsigned char date) { }

//字符发送函数

void putchar(unsigned char data1) {

SBUF = data1; //将待发送的字符送入发送缓冲器 while(TI == 0); //等待发送完成 TI = 0; //发送中断标志请0 } //主函数 void main(void) {

SCON = 0x50; //串口方式1 ，允许接收 TMOD = 0x20; //T1工作于方式2 PCON = 0x00; //波特率不倍增 TL1 = 0xfd; //波特率设置 TH1 = 0xfd; //

EA = 1; //开总中断 ES = 1; //开串口接收中断 TR1 = 1; //定时器开启 delay(200); delay(50); while(1)

18

DIG = date;

{ } }

19