>         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.

Interrupt handler:
reset           org     h'00'           ;reset vector
                goto    init
                org     h'04'           ;interrupt vector
                PUSH                    ;store valuables
                btfsc   INTCON,RBIF     ;test for portB interrupt
                call    intonb          ;portB isr
                btfsc   PIR1,RCIF       ;test for async rx interrupt
                call    asyncrx         ;serial rx isr
                btfsc   PIR1,TMR1IF     ;test for timer1 interrupt
                call    timeout1        ;timer1 isr
                ;btfss  PIR1,TXIF       ;test for async tx interrupt
                ;call   asynctx         ;serial tx isr
                ;btfsc  INTCON,T0IF     ;test for timer0 interrupt
                ;call   timeout0        ;timer0 isr
                ;btfsc  PIR1,TMR2IF     ;test for timer2 interrupt
                ;call   timeout2        ;timer2 isr
                ;btfsc  PIR1,SSPIF      ;test for spi interrupt
                ;call   donespi         ;spi isr
                PULL                    ;restore valuables
                retfie
and ISR:
asyncrx:                                ;serial rx isr
                btfsc   RCSTA,OERR      ;check for overrun error
                call    commserrors     ;cleared by clearing cren
                btfsc   RCSTA,FERR      ;check for framing error
                call    commserrors     ;cleared by reading rcreg
                movf    RCV1,F
                skpz
                call    commserrors     ;flag overrun
                movf    RCREG,W         ;get new data
                movwf   RCV1
                movf    RCV1,W
                sublw   h'52'           ;='R'?
                skpz
                retlw   0
                bcf     KEYBUFF,UP
                bcf     KEYBUFF,DOWN
                retlw   0
commserrors:                            ;report comms errors
                bsf     MOREFLAGS,OVERRUN;set rx error flag here
                bcf     RCSTA,CREN      ;clear cren
                bsf     RCSTA,CREN      ;reset cren
                retlw   0

This works fine even on the buggy 65A with BRGH set. I've got a 455KHz
clock, and run at 9600 baud.

Does this help?

* Alex_Barrett@iee.org
Robert Cooke Electronics, Norwich, UK