Changing code with 9600 baud rate to 4800

Regarding Baud rate

The code shown below which is of 9600 baud rate i want to change for 4800
Please guide me

/*------------------------------------------------------------------------------
Serial.c
------------------------------------------------------------------------------*/

#include <REG52.H> /* special function register declarations */
/* for the intended 8051 derivative */

#include <stdio.h> /* prototype declarations for I/O functions */


#ifdef MONITOR51 /* Debugging with Monitor-51 needs */
char code reserve [3] _at_ 0x23; /* space for serial interrupt if */
#endif /* Stop Exection with Serial Intr. */
/* is enabled */

/*------------------------------------------------
The delay function
------------------------------------------------*/
void Delay (const unsigned int DELAY)
{
unsigned int x, y;
for (x = 0; x <= DELAY; x++)
{
for (y = 0; y <= 120; y++);
}
}

/*------------------------------------------------
The main C function. Program execution starts
here after stack initialization.
------------------------------------------------*/
void main (void) {

/*------------------------------------------------
Setup the serial port for 9600 baud at 11.0952 MHz.
------------------------------------------------*/
#ifndef MONITOR51
SCON = 0x42; /* SCON: mode 1, 8-bit UART, enable rcvr */
TMOD |= 0x20; /* TMOD: timer 1, mode 2, 8-bit reload */
TH1 = 0xFD; /* TH1: reload value for 9600 baud @ 11.0592 MHz */
TR1 = 1; /* TR1: timer 1 run */
TI = 1; /* TI: set TI to send first char of UART */
#endif

/*------------------------------------------------
Note that an embedded program never exits (because
there is no operating system to return to). It
must loop and execute forever.
------------------------------------------------*/
while (1)
{
P1 ^= 0x01; /* Toggle P1.0 each time we print */
Delay(2000);
printf ("Gprmc, utc, date, Time, Lat, Long, Speed"); /*Print "Character Data" */
}
}

Re: Regarding Baud rate

Change the TH1 reload value from FDh to FAh ..

Regards,
IanP

Re: Regarding Baud rate

Please can you explain me how to calculate the bard rate Is there is any formula?

Re: Regarding Baud rate

This info (including formulas) is readily available on the web ..
For example, here:
"Setting the Serial Port Baud Rate"
**broken link removed**

Regards,
IanP

Re: Regarding Baud rate

Can you help me how to write a program to receive and to transmit the data in uart of 89c52, 4800 baud rate

Please

Re: Regarding Baud rate

You need tree functions:

void initBaudRate(void)
{
SCON = 0x42; /* SCON: mode 1, 8-bit UART, enable rcvr */
TMOD |= 0x20; /* TMOD: timer 1, mode 2, 8-bit reload */
TH1 = 0xFA; /* TH1: reload value for 4800 baud @ 11.0592 MHz */
TR1 = 1; /* TR1: timer 1 run */
TI = 1; /* TI: set TI to send first char of UART */
}

unsigned char uartSend(unsigned char uc)
{
while(TI==0)
; /* wait until transmiter empty */
TI = 0;
SBUF = uc; /* send char */
return uc;
}

unsigned char uartGet(void)
{
unsigned char uc;
while(RI==0)
; /* wait for char */
uc =SBUF; /* read the received char */
RI = 0;
return uc;
}

Added after 19 minutes:

The formulas for baudrate in modes 1 and 3 are:

BaudRate = (1+SMOD)•(fXTAL/ 12 ) / (32•(256-TH1)) = (1+SMOD)•(fXTAL/ 384) / (256-TH1)

TH1 = 256 – (1+SMOD)•(fXTAL/ 384) / BaudRate

TH1 = 256 – (fXTAL/ 384) / BaudRate if SMOD = 0
TH1 = 256 – (fXTAL/ 192) / BaudRate if SMOD = 1

You can use a better initBaudRate function:

void initBaudRate(unsigned baudrate)
{
PCON |= 0x80; /* SMOD = 1 */
SCON = 0x42; /* SCON: mode 1, 8-bit UART, enable rcvr */
TMOD |= 0x20; /* TMOD: timer 1, mode 2, 8-bit reload */
TH1 = (unsigned char)(256 – ((fXTAL/ 384) / BaudRate))
TR1 = 1; /* TR1: timer 1 run */
TI = 1; /* TI: set TI to send first char of UART */
}

Re: Regarding Baud rate

hey i dont know about c but in assembly you just change the value in scon