;********************************************************************
; APPLICATION PROGRAM FOR SERIAL RS 232 WITH 89C51
; SERIAL PORT CONFIGURATION: 	BIT PER SECOND-	2400
; 				DATA BIT	8
;				PARITY		NONE
;				STOP BITS	1
;				FLOW CONTROL	HARDWARE 
; MCU 89C51 PIN NO.11				
;********************************************************************
;    	e-mail: goswamigagan@rediffmail.com
;       
;*******************************************************
      ORG     0000H
                LJMP    BEGIN           ;POWER-ON RESET

                ORG     0003H
                LJMP    INT0_ISR        ;EXTERNAL INTERRUPT 0

                ORG     000BH
                LJMP    TMR0_ISR        ;TIMER 0 OVERFLOW

                ORG     0013H
                LJMP    INT1_ISR        ;EXTERNAL INTERRUPT 1

                ORG     001BH
                LJMP    TMR1_ISR        ;TIMER 1 OVERFLOW

                ORG     0023H
                LJMP    SERIAL          ;UART RX/TX INTERRUPT

                ORG     002BH
                LJMP    TMR2_ISR        ;TIMER 2 OVERFLOW
;
;********************************************************************
; BYTE VARIABLES IN DIRECTLY ADDRESSABLE INTERNAL MEMORY SPACE
;
        DSEG    AT      30H

RINT:   DS      1
CHECK:  DS      1
;
;********************************************************************
; BYTE VARIABLES IN INDIRECTLY ADDRESSABLE INTERNAL MEMORY SPACE
;
        ISEG    AT      80H

RIND:   DS      1
;
;********************************************************************
; BYTE VARIABLES IN EXTERNAL DATA MEMORY SPACE
;
        XSEG    AT      0000H

REXT:   DS      1

;

;********************************************************************
; BIT VARIABLES
;
        BSEG    AT      00H

TST_FLG:        DBIT    1

;********************************************************************
; MAIN PROGRAM STARTS HERE
;
        CSEG
BEGIN:          MOV     A,#47H         ;GAGAN SEND TO SERIAL PORT P3.1 PIN NO. 11
                LCALL   SERIAL1
                MOV     A,#41H
                LCALL   SERIAL1
                MOV     A,#47H
                LCALL   SERIAL1
                MOV     A,#41H
                LCALL   SERIAL1
                MOV     A,#4EH
                LCALL   SERIAL1
                SJMP    BEGIN


;
;********************************************************************
; FUNCTIONS/SUBROUTINES
SERIAL1:        MOV     TMOD,#20H
                MOV     TH1,#0F3H    ;BAUD RATE 2400
                MOV     SCON,#50H    ;8-BIT, 1 STOP BIT, REN ENABLED  
                SETB    TCON.6
               
                
XMIT:           MOV     SBUF,A          ;TRANMIT SERIAL DATA
                JNB     SCON.1,$
                CLR     SCON.1

                RET

;********************************************************************
; INTERRUPT SERVICE ROUTINES
;********************************************************************
;
INT0_ISR:       NOP
                RETI
;
;********************************************************************
;
TMR0_ISR:       NOP
                RETI
;
;********************************************************************
;
INT1_ISR:       NOP
                RETI
;
;********************************************************************
;
TMR1_ISR:       NOP
                RETI
;
;********************************************************************
;
SERIAL:         NOP
                RETI
;
;********************************************************************
;
TMR2_ISR:       NOP
                RETI
;********************************************************************
;
END