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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: 1634
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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