We are to write two programs-one without debounce and one with it-even the program with debounce didn't work. It looked like this:

.ORG 2000H
MOV A,#9FH ;SET UP
MOV DPTR,#0F803H ; PORT A
MOVX @DPTR,A ; AS AN INPUT
MOV A,#89H ;SET UP
MOV DPTR,#0F903H ; PORT E
MOVX @DPTR,A ; AS AN OUTPUT
MOV 40H,#00 ;CLEAR FLAG-IS LED ON/OFF
MOV A,#0FFH
MOV DPTR,#0F901H ;POINT TO PORT E
MOVX @DPTR,A ;TURN OFF ALL LED ATTACHED TO PORT E
DELAY:ACALL DLY250 ;CALL DELAY(SWITCH BOUNCE)
READ:MOV DPTR,#0F800H ;POINT TO PORT A
MOVX A,@DPTR
JNZ DELAY ;
MOV A,40H ;MONITOR FLAG
JNZ CLEAR ;
INC 40H ;SET FLAG
MOV DPTR,#0F901H ;POINT TO PORT E
MOV A,#0FEH ;
MOVX @DPTR,A ;TURN ON LED
SJMP DELAY
CLEAR:DEC 40H ;CLEAR FLAG
MOV DPTR,#0F901H ;POINT TO PORT E
MOV A,#0FFH ;
MOVX @DPTR,A ;TURN OFF LED
SJMP DELAY

DLY250:MOV R3,#3
LOOP:MOV R4,#150
LOOP1:MOV R5,#255
LOOP2:NOP
DJNZ R5,LOOP2
DJNZ R4,LOOP1
DJNZ R3,LOOP
RET