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9 bits or 8 bits parity=E

 
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Coni
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9 bits or 8 bits parity=E
PostPosted: Tue May 02, 2006 11:13 pm     Reply with quote

Hello

I need some help with a very basic issue. I'm trying to use the following code:

Code:
#include <16F877A.h>
#fuses NOPROTECT, XT, NOWDT, PUT, NOLVP, BROWNOUT
#use delay(clock=3579500)
#use rs232(baud=9600, xmit=PIN_C6, rcv=PIN_C7, bits=9)

char c;

main() {


   setup_adc(ADC_OFF); 
   SET_TRIS_C( 0x80 );

   while (TRUE) {

   c=getc();
   putc(c);
     }

}

It compiles but it doesn't do anything ( once programmed on the PIC). If I try with 8 bits it works fine but with 9 it doesn't .I'm using hyperterminal, and all I want for now is to be able to detect errors. Please help Crying or Very sad
Thanks
asmallri



Joined: 12 Aug 2004
Posts: 1635
Location: Perth, Australia

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Re: 9 bits or 8 bits parity=E
PostPosted: Tue May 02, 2006 11:59 pm     Reply with quote

Coni wrote:

It compiles but it doesn't do anything ( once programmed on the PIC). If I try with 8 bits it works fine but with 9 it doesn't .I'm using hyperterminal, and all I want for now is to be able to detect errors. Please help Crying or Very sad
Thanks


Hyperterm only supports 7 or 8 data bits.
_________________
Regards, Andrew

http://www.brushelectronics.com/software
Home of Ethernet, SD card and Encrypted Serial Bootloaders for PICs!!
Coni
Guest







PostPosted: Wed May 03, 2006 9:32 am     Reply with quote

Thanks for you answer.
But if I want to use 8 bits and even /odd parity ( in hyperterminal) it doesn't work either Sad
Thanks
Javiere
Guest







9 bits or 8 bits parity=E
PostPosted: Wed May 17, 2006 9:16 am     Reply with quote

I have de same problem:

I� am developing a ModBus slave device and I need work with an interfaz RS-232 at 9600 bauds, 8 data bits, 1 even parity and 1 stop bit.

I utilise the PIC18F4620 with the CCS C compiler version 3.239.

My problem consists in that I can�t detect the parity errors.

My program utilizes the next code:

#use delay(clock=20000000,RESTART_WDT)
#use rs232(baud=9600,parity=E,xmit=PIN_C6,rcv=PIN_C7,bits=8,enable=PIN_C5,restart_wdt,errors,stream=HOST)
#bit parityError=rs232_errors.0

��.

#int_RDA
void RDA_isr ()
{
if (!parityError)
{
car = fgetc (HOST);
// processCar (car);
}
else
{
fgetc (HOST); // Discard the character.
}
}

With this code the transmission is Ok but in the reception y have a lot of wrong characters that look like good viewing with the oscilloscope.

�Have you got any example that shows the use of the check of the parity error?

Thank you very much.
PCM programmer



Joined: 06 Sep 2003
Posts: 21708

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PostPosted: Wed May 17, 2006 9:44 am     Reply with quote

The parity is calculated in software by the CCS fgetc() function.
So you have to call fgetc() first, in order to get the parity information.
Example:

Code:

#int_RDA
void RDA_isr()
{
int8 car;

car = fgetc(HOST);

if(!parityError)
  {
   // processCar(car);
  }

}
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