8051 serial port enable

[Hareesh Kumar]

#include <reg52.h>

void delay_max()
{
unsigned int i=0,j=0;
for(j=0; j<100; j++)
for(i=0; i<6000; ++i);
}

void main(void){

TMOD |= 0x20; //use Timer 1, mode 2
TH1=0xFD; //9600 baud rate
SCON=0x50;
TR1=1; //start timer
//RI=0;
//TI=0;
while (1) {

SBUF=0x0A; //place value in buffer
while (TI==0); //wait until transmitted
TI=0;

delay_max();

SBUF=0x0F; //place value in buffer
while (TI==0); //wait until transmitted
TI=0;

delay_max();
}
}
i used this code for enabling serial communication in hyperterminal but connection is geting,not geting corect result in the hyperterminal...settings are alright...

 

[bigdogguru]

What's is the exact make and model of the of the 8051 you are using?

And what is the crystal frequency as well.

Are you getting any characters or garbage on the hyperterminal?

 

[ckshivaram]

what characters you get on the window........ is it purposeful that you have put it in an infinite loop???????? you will get ascii value of these in the terminal window only.......

what do you expect the result????

---------- Post added at 11:32 ---------- Previous post was at 11:30 ----------

you will get * and / when it prints.........

 

[Hareesh Kumar]

iam getting a symbol like * in hyperterminal..but in keil debugger i can see the corect values 0x0f and 0x0a

 

[ckshivaram]

hyperterminal will only show * and /

 

[bigdogguru]

Well 0x0A is the ASCII value for a linefeed (LF) and 0x0F is the ASCII value for the Shift In (SI) which may appear as a little star.

Try modifying your code:

#include <reg52.h>

void delay_max()
{
unsigned int i=0,j=0;
for(j=0; j<100; j++)
for(i=0; i<6000; ++i);
}

void main(void){

TMOD |= 0x20; //use Timer 1, mode 2
TH1=0xFD; //9600 baud rate
SCON=0x50;
TR1=1; //start timer
//RI=0;
//TI=0; 
while (1) {

SBUF='A';       //place ASCII value Character 'A' in buffer
while (TI==0); //wait until transmitted
TI=0;

delay_max();

SBUF='F';       //place ASCII value Character 'F' in buffer
while (TI==0); //wait until transmitted
TI=0;

delay_max();
}
}

This should improve your output, dont't confuse hex with ASCII Values:

**broken link removed**

 

[Hareesh Kumar]

how can i enable timer 2 for serial communication?what the value of registers in that situation?

 

[ckshivaram]

see this its explained clearly...
How Do I Set the Baud-Rate for the 8051’s Dedicated UART?