Display character typed ( Input from user )

 

  Code : 

#include<reg51.h>                        // Include 8051 library 

void ser_init();                               // Initialize serial communications.

void tx(unsigned char w);              // Serial transmission function definition.

unsigned char d;                            // Store the character received from user temporary.

unsigned char rx();                        // Serial receive function definition.

void main()                                        // Main function starts.

{

ser_init();                                   // Serial function calling.

d=rx();                                       // Receive data and store it in d.

tx(d);                                          // Transmit data stored in d.

}

void tx(unsigned char w)          // Transmit function.
{
SBUF = w;                    // SBUF temporary buffer location where character is stored.
while(TI==0);               // Wait until transmission completed flag gets high.
TI=0;                             // Once high , make it zero for the next character. 
}

unsigned char rx()                  // Receive function.

{

while(RI==0);                 // Wait while receive flag is not high.

RI=0;                               // Reset the receive flag.

return SBUF;                   // Return data received in SBUF.

}

void ser_init()                     // Serial transmission function
{
SCON = 0X50;           // Mode 1 (8-bit UART ) 
TMOD = 0X20;          // Timer 1 in Mode 2.
TH1 = 0XFD;            // Baud rate of 9600.
TR1 = 1;                     // Timer run flag enabled.
}

  :  Circuit Diagram

A terminal window is connected to microcontroller 

for serial comm. 

 

 RxD of  8051 is connected to TxD of terminal.

TxD of  8051 is connected to RxD of terminal.

Character Output Results : 

The character that you type gets immediately displayed on the screen.