8051 development board Exp.9 74ls138 74hc138 3 to 8 decoder reverser assembly code tutorial

org 0000h
ajmp main
org 0080h;
AA EQU P1.0
BB EQU P1.1
CC EQU P1.2
MAIN:
CLR CC ;
CLR BB
CLR AA
CALL DELAY ;
CLR CC ;
CLR BB
SETB AA
CALL DELAY ;
CLR CC ;
SETB BB
CLR AA
CALL DELAY
CLR CC
SETB BB
SETB AA
CALL DELAY
SETB CC
CLR BB
CLR AA
CALL DELAY
SETB CC
CLR BB
SETB AA
CALL DELAY
SETB CC
SETB BB
CLR AA
CALL DELAY
SETB CC
SETB BB
SETB AA
CALL DELAY
JMP MAIN ;
DELAY:
MOV R5,#255
D3:MOV R2,#255
D4: DJNZ R2,D4
DJNZ R5,D3
RET
END