7.1-4.c

单片机应用开发实例.rar

#include <stdio.h>
#include <reg51.h>

void putch(unsigned char);
unsigned char getch(void);

main()
{
 unsigned char ch;

 SCON = 0x50; 
 TMOD |= 0x20; 
 TH1 = 0xfd; 
 TL1 = 0xfd;
 TR1 = 1; 
 TI = 1; 
 RI = 0; 

 while(1)
{
  ch = getchar();
putchar(ch);

 }
}
void putchar(unsigned char ch) 
{

 SBUF = ch;
 TI = 0;
 while(!TI);
}
unsigned char getchar(void) 
{
 while(!RI);
 RI = 0;
 return(SBUF);
}