Keyboard Interrupt (S08Kbiv2); Introduction; Kbi Clock Gating; Features - ROHS MC9S08QE128 Reference Manual

Chapter 7

Keyboard Interrupt (S08KBIV2)

7.1

Introduction

The keyboard interrupt (KBI) module provides up to eight independently enabled external interrupt
sources. MC9S08QE128 Series devices contain two KBI modules, called KBI1 and KBI2. Each KBI
module has up to eight interrupt sources.
7.1.1

KBI Clock Gating

The bus clock to the KBI can be gated on and off using the KBI bit in SCGC2. This bit is set after any
reset, which enables the bus clock to this module. To conserve power, the KBI bit can be cleared to disable
the clock to this module when not in use. See
7.1.2

Features

The KBI features include:
• Up to eight keyboard interrupt pins with individual pin enable bits.
• Each keyboard interrupt pin is programmable as falling edge (or rising edge) only, or both falling
edge and low level (or both rising edge and high level) interrupt sensitivity.
• One software enabled keyboard interrupt.
• Exit from low-power modes.
7.1.3

Modes of Operation

This section defines the KBI operation in wait, stop, and background debug modes.
7.1.3.1 KBI in Wait Mode
The KBI continues to operate in wait mode if enabled before executing the WAIT instruction. Therefore,
an enabled KBI pin (KBPEx = 1) can be used to bring the MCU out of wait mode if the KBI interrupt is
enabled (KBIE = 1).
7.1.3.2 KBI in Stop Modes
The KBI operates asynchronously in stop3 mode if enabled before executing the STOP instruction.
Therefore, an enabled KBI pin (KBPEx = 1) can be used to bring the MCU out of stop3 mode if the KBI
interrupt is enabled (KBIE = 1).
Freescale Semiconductor
Section 5.7, "Peripheral Clock
MC9S08QE128 MCU Series Reference Manual, Rev. 2
Gating," for details.
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