Interrupt dengan Prioritas

$MOD51
 CSEG
 ORG 4000H
 LJMP START
 ORG 4003H
 LJMP INTER0
 ORG 4013H
 LJMP INTER1
 ORG 4100H

INTER0: MOV P1,#00H
 SETB P1.0
 LCALL LDELAY
 CLR P1.0
 RETI
 
INTER1: MOV P1,#0H
 SETB P1.7
 LCALL LDELAY
 CLR P1.7
 RETI
 ORG 4200H
 
LDELAY: PUSH 7
 PUSH 6
 PUSH 5
 MOV R7,#24H
LUPA: MOV R6,#0FFH
LUPB: MOV R5,#0FFH
 DJNZ R5,$
 DJNZ R6,LUPB
 DJNZ R7,LUPA
 POP 5
 POP 6
 POP 7
 RET
 
SDELAY: PUSH 7
 PUSH 6
 PUSH 5
 MOV R7,#04H
LUP1: MOV R6,#0FFH
LUP2: MOV R5,#0FFH
 DJNZ R5,$
 DJNZ R6,LUP2
 DJNZ R7,LUP1
 POP 5
 POP 6
 POP 7
 RET
 
START: MOV SP,#30H
       MOV TCON,#05H
       MOV IP,#04H
       MOV IE,#85H
       
LOOP1: MOV P1,#01010101B
       ACALL SDELAY
       MOV P1,#10101010B
       ACALL SDELAY
       SJMP LOOP1
       END