Thanks! Your advise helped me to locate the problem! The pins on the female
socket were reversed by misunderstanding of the schematic, I realise that
when I was trying to make the HyperTerminal to talk to its self.

Now I have my own example running and I will make the required changes to
adopt it to my future applications when needed. I am providing the code
below just to look at it as an experienced PIC user (compared to the
beginner me) and comment if there is a better way to do some things.

Haris

;This fragment of code receives a character from a terminal through RS-232
;and sends it back plus "OK"

 bsf STATUS,RP0 ;Goto Bank 1
 bsf TRISC, 7   ;Set bits 6,7 as specified in the
 bsf TRISC, 6   ;datasheet
 clrf TXSTA     ;Clear TX control register.
 bsf TXSTA,TXEN  ;Enable Transmit
 bcf TXSTA,BRGH  ;Select low speed baud rate
 movlw .51        ;constant for 1200 baud
 movwf SPBRG      ;Load the constant for 1200 baud
 bcf STATUS, RP0  ;Back to bank 0
 bsf RCSTA,SPEN   ;Enable Serial RX
 bcf RCSTA,RX9    ;Select 8bit RX
 bsf RCSTA, CREN  ;Enable continuous RX

loop    btfss PIR1, RCIF   ;Wait for RX
 goto loop    ;
 movf RCREG, w    ;Get the char
 bcf PIR1, RCIF     ; clear char. present flag
 movwf TXREG    ;Send the char. back
 movlw 'O'          ;Send OK
 movwf TXREG
 bsf STATUS, RP0  ;bank 1
wait    btfss TXSTA, TRMT  ;Is TSR Reg. Empty i.e. Ready to send new char?
 goto wait          ;No? wait a while
 bcf STATUS, RP0  ;Back to bank 0
 movlw 'K'
 movwf TXREG
 goto loop          ;go back


----- Original Message -----
From: "Bob Barr" <bbarr@CALIFORNIA.COM>
To: <PICLIST@MITVMA.MIT.EDU>
Sent: Saturday, December 29, 2001 8:22 PM
Subject: Re: [PIC]:16F877 MAX232 RS-232 to PC Example Request
>
> Luck has very little to do with RS-232 interfacing; you need to use a
> bit of witchcraft. :=) Part of the witchcraft involves breaking down
> the problem into smaller chunks.
>
>
> 1) Hardware connection -
>
> You don't say so here but you did connect the Signal Ground as well,
> didn't you? :=)
>
>
> 2) Handshaking -
>
> Try jumpering the Tx to Rx at the cable end (without your board
> connected). Can Hyperterminal talk to itself? You should see the
> characters echoed as you type them. If not, there is either a
> connection or a handshaking problem. You can either turn off the
> handshaking in Hyperterminal or jumper the handshake signals at your
> board.
>
> [Note: If you change the settings in Hyperterminal, you need to exit
> and restart Hyperterminal to get the new settings to take effect. I'm
> not sure why this is necessary but it just seems to be the case. There
> may be another method to accomplish this but I don't know what it may
> be.]
>
> 3) PIC to Hyperterminal -
>
> Once you have Hyperterminal able to talk to itself, you can then set
> up your PIC code to loop repeatedly sending a character to the PC. If
> this works, then you've got the Tx and Rx right and the baud rate and
> parity are the same at both ends. If not, you'll need to get them set
> the same.
>
>
> Breaking the interfacing down into these smaller steps may help you
> diagnose the problem. Good luck.
>
> Regards, Bob
>
> --
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>
>

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