MC908KX2MDWE Datasheet, PDF(95/210 Page) Freescale Semiconductor, Inc – High-performance M68HC08 architecture, Fully upward-compatible object code with M6805, M146805, and M68HC05 Families

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MC908KX2MDWE Datasheet, PDF (95/210 Pages) Freescale Semiconductor, Inc – High-performance M68HC08 architecture, Fully upward-compatible object code with M6805, M146805, and M68HC05 Families

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Chapter 9

Keyboard Interrupt Module (KBI)

9.1 Introduction

The keyboard interrupt module (KBI) provides five independently maskable external interrupt pins.

9.2 Features

KBI features include:

â¢ Five keyboard interrupt pins, on the MC68HC08KX8, are with separate keyboard interrupt enable

bits and one keyboard interrupt mask

â¢ Hysteresis buffers

â¢ Programmable edge-only or edge- and level-interrupt sensitivity

â¢ Automatic interrupt acknowledge

â¢ Exit from low-power modes

INTERNAL BUS

KBD0

TO PULLUP

ENABLE

.

.

KB0IE

.

KBD4

or KBD3

TO PULLUP

ENABLE

KB4IE or KB3IE

VDD

CLR

D

Q

CK

ACKK

RESET

VECTOR FETCH

DECODER

KEYF

SYNCHRONIZER

MODEK

KEYBOARD

INTERRUPT FF

IMASKK

KEYBOARD

INTERRUPT

REQUEST

Figure 9-1. Keyboard Module Block Diagram

MC68HC908KX8 â¢ MC68HC908KX2 â¢ MC68HC08KX8 Data Sheet, Rev. 2.1

Freescale Semiconductor

95

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