The 8051 Microcontroller and Embedded

Department of Computer Scien

ce and Information Engineering

National Cheng Kung University, TAIWAN

HANEL

INTERRUPTSSix Interrupts in 8051

(cont’)

0023

Serial COM (RI and TI)

001B

Timer 1 (TF1)

P3.3 (13)

0013

External HW (INT1)

000B

Timer 0 (TF0)

P3.2 (12)

0003

External HW (INT0)

9

0000

Reset

Pin

ROM Location (hex)

Interrupt
Interrupt vector table

ORG 0 ;

wake-up ROM reset location

LJMP MAIN ;by-pass int. vector table

;---- the wake-up program

ORG 30H

MAIN:

....END

Only three bytes of ROM space assigned to the reset pin. We put the LJMP as the first instruction and redirect the processor away from the interrupt vector table.