Thanks for the suggestions, now I adapted the code :)
In fact, now I put directly the value 25 in SPBRG, which is for 9600 baud rate, at 4 MHz (that's what I understood from a microchip application note). Is this value correct for my setup ? The TX interrupts are enabled when the send buffer has something and disabled when empty. The code for the ISR is inspired from an example from HT-PIC C Compiler, so I thought it is correct. If I deactivate the flag in the main loop, is it correct ?

        if(RCIF) {
                led2_on();
                receivebuffer[RecvBufferPos] = RCREG;

                if ((++RecvBufferPos)==MAXRECEIVEBUFFER) RecvBufferPos = 0;
                led2_off();
        }
        if(TXIF && TXIE)
        {
                led1_on();
                TXREG = sendbuffer[SendBufferPos];
                if ((++SendBufferPos)==MAXSENDBUFFER) SendBufferPos=0;
                led1_off();
        }
        sci_CheckOERR();

I tried all this, but still, it is not functioning :( It acts like it ignores the serial part, the links are not blinking when they should (they are supposed to blink when a byte is transmitted). Any ideas are welcomed.

Lucian
-----Original Message-----
From: pic microcontroller discussion list [mailto:PICLIST@MITVMA.MIT.EDU] On Behalf Of piclist@XARGS.COM
Sent: 4 octombrie 2003 19:07
To: PICLIST@MITVMA.MIT.EDU
Subject: Re: [PIC]: 16F628 USART Problem

On Sat, 4 Oct 2003, Lucian wrote:

>         tmp = 16UL * baud;
>         X = (int)(XTAL/tmp) - 1;

How are "tmp" and "X" declared?  How is "XTAL" defined?

>         TXIE = 1;       /* enable tx interrupts */

You don't want to turn on transmit interrupts until you have something to transmit.  Is your transmit buffer initialized at this point?

>         if(TXIF && TXIE)
>         {
>                 led1_on();
>                 if(SendBufferPos == SendBufferRecPos)
>                         TXEN = 0;

You wouldn't normally want to disable the transmitter in your ISR, because the transmitter is still active after your ISR has finished loading bytes into TXREG.

>                         sci_PutByte(sendbuffer[SendBufferPos]);

What does this function do?  You don't need to call a function to place a byte in TXREG.

--
John W. Temples, III

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Lucian


----

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