MC9S08GT16 MOTOROLA [Motorola, Inc], MC9S08GT16 Datasheet - Page 145

• Manufacturer Part Number: MC9S08GT16
• Description: Microcontrollers
• Manufacturer: MOTOROLA [Motorola, Inc]

Chapter 9 Keyboard Interrupt (KBI) Module
9.1
The MC9S08GB/GT has one KBI module with eight keyboard interrupt inputs that share port A pins. See
Chapter 2, “Pins and
pins.
9.1.1
The following paragraphs discuss controlling the keyboard interrupt pins.
Port A is an 8-bit port which is shared among the KBI keyboard interrupt inputs and general-purpose I/O.
The eight KBIPEn control bits in the KBIPE register allow selection of any combination of port A pins to
be assigned as KBI inputs. Any pins which are enabled as KBI inputs will be forced to act as inputs and
the remaining port A pins are available as general-purpose I/O pins controlled by the port A data (PTAD),
data direction (PTADD), and pullup enable (PTAPE) registers.
KBI inputs can be configured for edge-only sensitivity or edge-and-level sensitivity. Bits 3 through 0 of
port A are falling-edge/low-level sensitive while bits 7 through 4 can be configured for
rising-edge/high-level or for falling-edge/low-level sensitivity.
The eight PTAPEn control bits in the PTAPE register allow you to select whether an internal pullup device
is enabled on each port A pin that is configured as an input. When any of bits 7 through 4 of port A are
enabled as KBI inputs and are configured to detect rising edges/high levels, the pullup enable bits enable
pulldown rather than pullup devices.
An enabled keyboard interrupt can be used to wake the MCU from wait or standby (stop3).
9.2
The keyboard interrupt (KBI) module features include:
Freescale Semiconductor
•
Keyboard interrupts selectable on eight port pins:
— Four falling-edge/low-level sensitive
— Four falling-edge/low-level or rising-edge/high-level sensitive
— Choice of edge-only or edge-and-level sensitivity
— Common interrupt flag and interrupt enable control
— Capable of waking up the MCU from stop3 or wait mode
Introduction
Features
Port A and Keyboard Interrupt Pins
MCU Pin:
Connections” for more information about the logic and hardware aspects of these
KBI1P7
PTA7/
MC9S08GB/GT Data Sheet, Rev. 2.3
KBI1P6
PTA6/
Figure 9-1. Port A Pin Names
KBI1P5
PTA5/
KBI1P4
PTA4/
KBI1P3
PTA3/
KBI1P2
PTA2/
KBI1P1
PTA1/
KBI1P0
PTA0/
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