ORG      VECSCI
            FDB      SCI_ISR

            ORG      $C000
            lds      #$ff
INIT_SCI    LDX      #REGBAS
            CLR      SCCR1,X
            LDAA     #%00110000            ; 9600 BAUD
            STAA     BAUD,X
            LDAA     #%00101100            ; enable RX (RE=1;RIE=1)
            STAA     SCCR2,X               ; enable TX (TE=1)

            CLR      DDRC,X
            CLRB
            JSR      LCD
            CLI

*----------------------------------------------------------------------------

L00         LDAA     PORTC,X
            BPL      L00
            ANDA     #$7F
            STAA     PORTB,X
            LDAB     #%10101100            ; enable RX (RE=1;RIE=1)
            STAB     SCCR2,X               ; enable TX (TE=1;TIE=1)

L01         LDAA     PORTC,X
            BMI      L01
            ANDA     #$7F
            STAA     PORTB,X
            LDAB     #%10101100            ; enable RX (RE=1;RIE=1)
            STAB     SCCR2,X               ; enable TX (TE=1;TIE=1)

            BRA      L00

*----------------------------------------------------------------------------

SCI_ISR     BRSET    SCSR,X,RDRF,RX_ISR
            BRSET    SCSR,X,TDRE,TX_ISR
            BRA      SCI_RTI

RX_ISR      LDAB     SCDR,X                ;  reset vlag
            JSR      LCD
            BRA      SCI_RTI

*----------------------------------------------------------------------------

TX_ISR      STAA     SCDR,X
            LDAB     #%00101100            ; enable  RX (RE=1;RIE=1)
            STAB     SCCR2,X               ; disable TX (TE=1;TIE=0)

SCI_RTI     RTI

*----------------------------------------------------------------------------


$INCLUDE 'REGS.INC'
*$INCLUDE 'LCD.INC'
$INCLUDE 'SIMLCD.INC'