ORG 0 ; reset address
SJMP START ; jump over reserved area
ORG 13H ; INT1 address vector
SJMP TASK ; jump to interrupt routine
ORG 40H ; program start address
START: SETB IT1 ; interrupt edge triggered
SETB EA ; enable all set interrupts
SETB EX1 ; enable INT1 interrupt
AGAIN: SJMP AGAIN ; stay here till interrupt
TASK: CPL P1.7 ; interrupt task
RETI ; return from interrupt
END ; no more assembly language