PIC usart problem

 Hi everyone,
 I am having a big trouble with my PIC's serial communication. I have
codes like these:
GPS:
			CALL 	set4800
A0:		      CALL    RCread
			CALL	TXsend
			XORLW	'G'
			BNZ	 A0

	                MOVLW	0XFF
			MOVWF	PORTA
			RETURN
    I have incoming messages and I want to take the one which starts
with 'G', so I write these simple codes. Althoug I have sentences which
starts with 'G', PortA never gets FF. I tried these codes with Proteus
and it works. But it doesnt work with my pic16f877 in my circuit. From
TX output I get the bytes which I sent from RC, I see that there are
G's in RC but they dont make the port A to be FF. Please hellllppppp
me.
Here are my functions:
RCread:     bcf     STATUS,RP0      ; Select Bank 0.
getc1          btfss   PIR1,RCIF	   ; Skip if RC int flag set
	         goto    getc1           ; Try again
	         movf	   RCREG,W         ; Read the character
	         bcf     PIR1,RCIF       ; Clear the interrupt flag
	         return


TXsend  	bcf     STATUS,RP0      ; Select Bank 0.
putc1  		btfss   PIR1,TXIF         ; Skip if TXbuffer empty
	           goto    putc1           ; Try again
        	   movwf   TXREG           ; Write it!
	           bcf     STATUS,RP0      ; Select Bank 0.
		  return
set4800:	bsf		STATUS,RP0
			MOVLW	D'51'
			MOVWF	SPBRG
			movlw   0xA4            ; CSRC/TXEN (Internal clock, 8 bit mode,
Async
                                                         ;operation,
High Speed)
			movwf   TXSTA           ; Write to TX control register.
			BSF		TXSTA,BRGH
			BCF		STATUS,RP0 				;
			RETURN

ali.keles@gmail.com wrote:
> Hi everyone,
>  I am having a big trouble with my PIC's serial communication. I have
> codes like these:
> GPS:
> 			CALL 	set4800
> A0:		      CALL    RCread
> 			CALL	TXsend
> 			XORLW	'G'
> 			BNZ	 A0
>
> 	                MOVLW	0XFF
> 			MOVWF	PORTA
> 			RETURN
>     I have incoming messages and I want to take the one which starts
> with 'G', so I write these simple codes. Althoug I have sentences which
> starts with 'G', PortA never gets FF. I tried these codes with Proteus
> and it works. But it doesnt work with my pic16f877 in my circuit.

The problem may not be with this code (I can't see a bug either). Are
you initialising TRISA?

> From
> TX output I get the bytes which I sent from RC, I see that there are
> G's in RC but they dont make the port A to be FF. Please hellllppppp
> me.
> Here are my functions:
> RCread:     bcf     STATUS,RP0      ; Select Bank 0.
> getc1          btfss   PIR1,RCIF	   ; Skip if RC int flag set
> 	         goto    getc1           ; Try again
> 	         movf	   RCREG,W         ; Read the character
> 	         bcf     PIR1,RCIF       ; Clear the interrupt flag
> 	         return
>
>
> TXsend  	bcf     STATUS,RP0      ; Select Bank 0.
> putc1  		btfss   PIR1,TXIF         ; Skip if TXbuffer empty
> 	           goto    putc1           ; Try again
>         	   movwf   TXREG           ; Write it!
> 	           bcf     STATUS,RP0      ; Select Bank 0.
> 		  return
> set4800:	bsf		STATUS,RP0
> 			MOVLW	D'51'
> 			MOVWF	SPBRG
> 			movlw   0xA4            ; CSRC/TXEN (Internal clock, 8 bit mode,
> Async
>                                                          ;operation,
> High Speed)
> 			movwf   TXSTA           ; Write to TX control register.
> 			BSF		TXSTA,BRGH
> 			BCF		STATUS,RP0 				;
> 			RETURN

Hi,

Hope you have configured the PORTA as only digital, check the ADCON0
and ADCON1 register''


toby wrote:
> ali.keles@gmail.com wrote:
> > Hi everyone,
> >  I am having a big trouble with my PIC's serial communication. I have
> > codes like these:
> > GPS:
> > 			CALL 	set4800
> > A0:		      CALL    RCread
> > 			CALL	TXsend
> > 			XORLW	'G'
> > 			BNZ	 A0
> >
> > 	                MOVLW	0XFF
> > 			MOVWF	PORTA
> > 			RETURN
> >     I have incoming messages and I want to take the one which starts
> > with 'G', so I write these simple codes. Althoug I have sentences which
> > starts with 'G', PortA never gets FF. I tried these codes with Proteus
> > and it works. But it doesnt work with my pic16f877 in my circuit.
>
> The problem may not be with this code (I can't see a bug either). Are
> you initialising TRISA?
>
> > From
> > TX output I get the bytes which I sent from RC, I see that there are
> > G's in RC but they dont make the port A to be FF. Please hellllppppp
> > me.
> > Here are my functions:
> > RCread:     bcf     STATUS,RP0      ; Select Bank 0.
> > getc1          btfss   PIR1,RCIF	   ; Skip if RC int flag set
> > 	         goto    getc1           ; Try again
> > 	         movf	   RCREG,W         ; Read the character
> > 	         bcf     PIR1,RCIF       ; Clear the interrupt flag
> > 	         return
> >
> >
> > TXsend  	bcf     STATUS,RP0      ; Select Bank 0.
> > putc1  		btfss   PIR1,TXIF         ; Skip if TXbuffer empty
> > 	           goto    putc1           ; Try again
> >         	   movwf   TXREG           ; Write it!
> > 	           bcf     STATUS,RP0      ; Select Bank 0.
> > 		  return
> > set4800:	bsf		STATUS,RP0
> > 			MOVLW	D'51'
> > 			MOVWF	SPBRG
> > 			movlw   0xA4            ; CSRC/TXEN (Internal clock, 8 bit mode,
> > Async
> >                                                          ;operation,
> > High Speed)
> > 			movwf   TXSTA           ; Write to TX control register.
> > 			BSF		TXSTA,BRGH
> > 			BCF		STATUS,RP0 				;
> > 			RETURN

<ali.keles@gmail.com> wrote in message
news:1151333610.439573.258960@u72g2000cwu.googlegroups.com...
> Hi everyone,
>  I am having a big trouble with my PIC's serial communication. I have
> codes like these:

Try following the examples on www.piclist.com and then expand on them.  :)

You can get some pretty good bitrates out of the 40Mhz PICs clocked at 60Mhz
but have to guess the divisor-thingies almost (thoroughly untechnical term I
know).