BlankHave you written to the LCD by itself, without getting data from the
RS232 line? I had similar problems (wrong characters showing up) and they
were caused by faulty wiring between the PIC and the LCD, so when I thought
it was getting data it really was not on one line. If you are already seeing
things the PIC writes to the LCD on its own, then I guess the hardware is
fine.

Andy
----- Original Message -----
From: <Adriaan Nel>
To: PICLIST@MITVMA.MIT.EDU
Sent: Sunday, October 28, 2001 5:04 AM
Subject: [PIC:] Need help with USART on PIC16F628


Hi,

I need to implement communication from a terminal window, to the PIC using
it's USART function, and then writing the values out on a LCD, via a MAX232
IC.  I can communicate with moderate stability, the problem however is:
when I enter j on the terminal, it display's U on the LCD, the only
character that display's correctly is f, some of the others even displays
characters that doesn't exist in the ASCII table.

I have replaced the MAX232 IC with other makes, still the same problem, I
have also checked all the hardware, no problem there....

Here is a piece of my code, please help

As you will see, I need to txmit aswell, but I've taken that out for now...

Adriaan

usetp
 bcf 03,06
 bsf 03,05     ;bank1
 movlw d'25'  ;set SPBRG to 9600
 movwf 19h

 bsf 18,02  ;BRGH = High Speed
 bsf 18,05  ;TXEN
 bcf 18,04  ;Async mode
 bcf 18,06  ;8 bits

 bcf 03,05  ;bank0

 bsf 18,07  ;enable serial port

 bsf 03,05  ;bank1

 bsf 18,07  ;Internal clock

 bcf 03,05  ;bank0

 bcf 18,06  ;8 bits
 bsf 18,04  ;enable RX
 return

;---Receive Routine-------------------------------------------------------

rxdat
 movf 1A,0
 movwf readtmp
 return

;---Transmit Routine------------------------------------------------------

;txdat
; movwf 19h
; return

;---Initial main Routine (setup of LCD for USART characters)--------------

main
 call usetp
 bcf lcdprt,lcdcmd
 movlw b'00000111' ;increment
 movwf 06  ;display shift on
 movwf lcdr
 call pulse
 swapf lcdr,0
 movwf 06
 call pulse
 movlw b'00011000' ;display shift on
 movwf lcdr  ;left shift
 movwf 06
 call pulse
 swapf lcdr,0
 movwf 06
 call pulse
 movlw b'11001111' ;display address
 movwf lcdr
 movwf 06
 call pulse
 swapf lcdr,0
 movwf 06
 call pulse
 bsf lcdprt,lcdcmd

;---Secondary main Routine (RX and writing on LCD of USART values)--------

main2
 btfss 0C,05
 goto main2
 call rxdat
 movf readtmp,0
 movwf lcdr
 movwf 06
 call pulse
 swapf lcdr,0  ;swap nibbles
 movwf 06
 call pulse  ;write second nibble
 bcf 0C,05  ;clear RX flag
; movf readtmp,0

;---Tertiary main Routine (Continued from above, and TX)------------------

;main3
; btfss 0C,04
; goto main3
; call txdat
 goto main2
 end


_________________________________________________________
Do You Yahoo!?
Get your free @yahoo.com address at http://mail.yahoo.com


--
http://www.piclist.com hint: To leave the PICList
mailto:piclist-unsubscribe-request@mitvma.mit.edu