serial communicatin with pc in C18 compiler

[Munib]

how to set pll in c18 compiler

im interfacing my PIC 18f452 with my computer with windows XP as OS.

the problem is that i can not send my data correctly to the computer via COM1,

the data which uis received by the hyperterminal is not correct, i wrote a program IN MY COMPUTER WHICH GENRATED AN INTEGER , send it to my mcu via the serial port , the mcu got the data and then send the same data back t the PC,


now when my pc send "1" to mcu, it received 1 but it returned 129 to pc,
when send 2, the mcu returned 130,
and i concluded that the mcu returned the value with an addition of 128, but i was wrong this factor of 128 was not cnstant and it kept on changing

so far i was using C 18 compiler, when i used my mcu with pic basic pro, this problem didnt occur ,
is there ne thing wrong with C 18 or if iam doing ne thing wrong

 

[pirev]

c18 serial

Can you post MCC 18 code, when receive data from PC and when send it back to PC. How is defined your data: unsigned char or char ?

 

[metao]

rcsta port c18

cause of error may ..
1 error in broadrate timming
2 differance between sign data and unsign data
3 number of stop bit
4 number of bit per transmit

 

[Munib]

delay10ktcyx(8) - compiler (c18)

#include <p18f452.h>  /* for the special function register declarations */
#include <delays.h>
#pragma config OSC = HS

#pragma config WDT = OFF
#pragma config LVP = OFF

//char data_string[100];
 unsigned char i = 0;
unsigned char ch=0;
//int r = 0;

//~~~~~ START OF MAIN~~~~~~

void main()
{
TRISB=0;
PORTB=0;

//for ( r = 0 ; r < 100 ; r++)
//	data_string[r] = r;


TMR0H=0x00;
TMR0L=0x00;
SPBRG=0x0B;
RCSTA=0b10011001;
TXSTA=0b00100010;


//for (i=0 ; i<123 ; i++)
while(1)
{	
	while(PIR1bits.RCIF==0);
	
	//if(PIR1bits.RCIF==1)
	ch = RCREG;
	PORTB = ch;
    Delay10KTCYx(50);
	if (PIR1bits.TXIF)
	{	
/*			if(i%5 == 1 )
			{
				TXREG = '\n';
				while (TXSTAbits.TRMT==0);
			}//end of small if*/
			TXREG = (ch&0xFF);
			while (TXSTAbits.TRMT==0);

//			PORTB=data_string[i];
	}		

		
	// end of big if


}//end of for

/*	TXREG = '\0';
	while (TXSTAbits.TRMT==0);
*/
	//PORTB = 0xAA;
} // end of main

here is the cde which i have used for communication of pic with PC



here the baudrate is set by
SPBERG=0x0B

which is for 7.37MHz crystal, i have with me 8Mhz crystal, will it affect me, it didnot when i compiled this code in MIKRObasic, but answer goes awry if i use C18 compiler

, Also can any one give me some sample code which worked correctly for data transfer from MCU to PC using the C18 compilerr

 

[newfound]

7 bit serial c18

SPBERG=0x0B

Use SPBRG = 0xC for 9600 baud @ 8MHz, BRGH=0
This will probably fix the problem.

TXSTA=0b00100010;

This is wrong. Bit-1 is read only. Why are you writing a '1' to it?

RCSTA=0b10011001;

Now this is just silly. Did you read the data sheet?

Try
RCSTA = 0b10010000

(and do read the data sheet.) ;-)

Regards,

Jim Robertson
NEWFOUND ELECTRONICS

 

[Munib]

calculating baud rate in mcc18 compiler

ok
i will try out these new settings
but i would like to know
that how u concluded taht instead of 0x0B should be replaced 0x0C

ne way me out to check whether these new settings work or not,

Added after 1 hours 39 minutes:

and also if i want to know baud rates at other crystal configuartions

for example : for 7.73Mhz baudrate is 0x0B and u told that use 0x0C for 8 Mhz,
now if i also use PLL mode too, then what would be the baudrate then :S

 

[newfound]

pir1bits.rcif mikrobasic

ok
i will try out these new settings
but i would like to know
that how u concluded taht instead of 0x0B should be replaced 0x0C

ne way me out to check whether these new settings work or not,

Added after 1 hours 39 minutes:

and also if i want to know baud rates at other crystal configuartions

for example : for 7.73Mhz baudrate is 0x0B and u told that use 0x0C for 8 Mhz,
now if i also use PLL mode too, then what would be the baudrate then :S

Read the data sheet! ;-)

BRGH = 0

Baud Rate = FOSC/(64(x+1)

= 8000000/(64(13))

= 8000000/(832) = 9615 baud

With PLL

Baud Rate = FOSC/(64(x+1)

= 32000000/(64(13))

= 32000000/(832) = 38462 baud

Have a look at this file. **broken link removed**

It may also help.


Regards,

Jim Robertson
NEWFOUND ELECTRONICS