HI there

Thank you Andrew Warren for your last bit of advice
concerning the setting of bits.

I now have another problem with 16C74. I have written
a program that will receive 8-bits from a PC at 9600b/s
and display it on port B. It will then transmit those same
8-bits back to the PC. The problem is, it seems to put FFH
or FEH onto port B on matter what I send it and it transmits 00H
back. Occasionally it sends 01H back, but not often.
I put an LED onto port A,0 to indicate if it had any errors
but it never turns on. I'm using a 2.4576MHz crystal which
divides down and I load 03H into SPBRG.
I have BRGH cleared for low speed. If any one has the time,
please have a look at the program.

Thanks in advance

Gavin
vulcan@ihug.co.nz

                ORG             00H
                GOTO            START
                ORG             04H
                GOTO            ISR
START           CLRF            PORTB
                CLRF            PORTA
                BSF             STATUS,RP0      ;page 1
                CLRF            TRISA           ;port A output
                CLRF            TRISB           ;port B output
                MOVLW   07H
                MOVWF   ADCON1  ;select digital
                CLRF            PIE1
                BSF             PIE1,RCIE       ;rx int enable
                MOVLW   03H
                MOVWF   SPBRG           ;baud rate
                CLRF            TXSTA
                BSF             TXSTA,TXEN      ;tx enable
                BCF             STATUS,RP0      ;page 0
                CLRF            RCSTA
                BSF             RCSTA,SPEN      ;enable serial
                BSF             RCSTA,CREN
                CLRF            INTCON
                BSF             INTCON,PEIE     ;peripheral int enable
                BSF             INTCON,GIE      ;global int enable
                BSF             PORTA,1
LOOP            GOTO            LOOP

ISR             BCF             PORTA,1 ;indicate problem 1
                BCF             PORTA,0 ;clear problem 2
                MOVLW   06H
                ANDWF   RCSTA,W
                BTFSS           STATUS,Z
                GOTO            RXERROR
                BTFSS           PIR1,5
                RETFIE
                MOVF            RCREG,W ;read data received
                MOVWF   PORTB           ;show data received
                MOVWF   TXREG           ;tx back to PC
                BSF             PORTA,1 ;clear problem 1
                RETFIE
RXERROR BCF             RCSTA,CREN
                BSF             RCSTA,CREN
                MOVLW   0FFH
                MOVWF   PORTB
                BSF             PORTA,0 ;indicate problem 2
                RETFIE
                END