Hello Fred,

I use the 16C74 in a datalogger that send the measured data to a PC via RS232.
Here is the code fragment:


        LIST P=16C74
        include <p16c74.inc>

clockrate       equ .3686400         ;define clock rate here
baudrate        equ    .9600         ;define baud rate here
tim0            equ      .48
bdclk           equ      .24
RESET_V                 EQU             0x0000                  ; Address of RES
ET Vector

        ;RS232 **************
#define _tx             PORTC,6 ; TXD UART
#define _rx             PORTC,7 ; RXD UART


txregx          equ     0x20    ;used as temp transmit register
rcregx          equ     0x21    ;received char is saved here

       org     RESET_V                 ; RESET vector location
RESET       GOTO    START              ;

START                               ; POWER_ON Reset (Beginning of program)

                        ; INIT UART *********************************
            bsf         STATUS, RP0
            movlw       B'00100100'
            movwf       TXSTA
            movlw       bdclk
            movwf       SPBRG
            bcf         STATUS, RP0
            movlw       B'10010000'
            movwf       RCSTA
                        ;**********************************************
loop

        goto    loop



;************************************************************
; RS232 - Routines
;************************************************************

send                    ;Send Character via RS232
        movwf   txregx
send1
        btfss   PIR1,TXIF
        goto    send1
        movf    txregx,w
        movwf   TXREG
        return

;*******************************************************************
; Poll Characters via RS232
;*******************************************************************
prozedur
        btfss   PIR1,RCIF       ;Test if Character has been received
        goto    kein_zeichen

        movf    RCREG,W         ;Get Character
        movwf   rcregx
        movlw   0x01
        subwf   rcregx,W
        btfss   STATUS,Z
        goto    keine_anforderung

        ;........


keine_anforderung

        ;........


kein_zeichen

        return

        END

----------
Von:    Fred Thompson[SMTP:fthompso@MAIL.WIN.ORG]
Gesendet:       Donnerstag, 4. September 1997 17:47
An:     PICLIST@MITVMA.MIT.EDU
Betreff:        Serial Input for 16C74

        Would someone please post/send me a sample of source code that
correctly receives Async. serial using the hardware UART.  I have been
working on this problem for some time and still have not gotten anything
to work.  I would prefer interrupt driven, but I'm not picky.  Anything
that actually works would be a real help.

Fred Thompson
fthompso@mail.win.org