MC908QL4 FREESCALE [Freescale Semiconductor, Inc], MC908QL4 Datasheet - Page 89

• Manufacturer Part Number: MC908QL4
• Description: M68HC08 Microcontrollers
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

Chapter 9
Keyboard Interrupt Module (KBI)
9.1 Introduction
The keyboard interrupt module (KBI) provides independently maskable external interrupts.
The KBI shares its pins with general-purpose input/output (I/O) port pins. See
of these shared pins.
9.2 Features
Features of the keyboard interrupt module include:
9.3 Functional Description
The keyboard interrupt module controls the enabling/disabling of interrupt functions on the KBI pins.
These pins can be enabled/disabled independently of each other. See
9.3.1 Keyboard Operation
Writing to the KBIEx bits in the keyboard interrupt enable register (KBIER) independently enables or
disables each KBI pin. The polarity of the keyboard interrupt is controlled using the KBIPx bits in the
keyboard interrupt polarity register (KBIPR). Edge-only or edge and level sensitivity is controlled using the
MODEK bit in the keyboard status and control register (KBISCR).
Enabling a keyboard interrupt pin also enables its internal pullup or pulldown device based on the polarity
enabled and the corresponding port pullup/down enable bit, PTAPUEx see
Pullup/Down Enable
rising edge or high level detection, a pulldown device is configured.
Freescale Semiconductor
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Keyboard interrupt pins with separate keyboard interrupt enable bits and one keyboard interrupt
mask
Programmable edge-only or edge and level interrupt sensitivity
Edge sensitivity programmable for rising or falling edge
Level sensitivity programmable for high or low level
KBI can be configured to use either internal or external pullup/pulldown devices using PTAPUE,
see
–
Exit from low-power modes
When in internal device is enabled, pullup or pulldown device automatically configured based
on the polarity of edge or level detect
12.3.3 Port A Input Pullup/Down Enable Register
Register. On falling edge or low level detection, a pullup device is configured. On
MC68HC908QL4 Data Sheet, Rev. 7
Figure
12.3.3 Port A Input
Figure 9-1
9-2.
for port location
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