s908gz60cfa Freescale Semiconductor, Inc, s908gz60cfa Datasheet - Page 115

• Manufacturer Part Number: s908gz60cfa
• Description: M68hc08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

Chapter 9
Keyboard Interrupt Module (KBI)
9.1 Introduction
The keyboard interrupt module (KBI) provides eight independently maskable external interrupts which are
accessible via PTA0–PTA7. When a port pin is enabled for keyboard interrupt function, an internal
pullup/pulldown device is also enabled on the pin.
9.2 Features
Features include:
9.3 Functional Description
Writing to the KBIE7–KBIE0 bits in the keyboard interrupt enable register independently enables or
disables each port A pin as a keyboard interrupt pin. Enabling a keyboard interrupt pin also enables its
internal pullup/pulldown device. On falling edge or low level selection a pullup device is configured. On
rising edge or high level selection a pulldown device is configured.
A keyboard interrupt is latched when one or more keyboard pins are asserted. The MODEK bit in the
keyboard status and control register controls the triggering mode of the keyboard interrupt.
Freescale Semiconductor
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Eight keyboard interrupt pins with separate keyboard interrupt enable bits and one keyboard
interrupt mask
Hysteresis buffers
Programmable edge-only or edge- and level- interrupt sensitivity
Edge detect programmable for rising or falling edges
Level detect programmable for high or low levels
Exit from low-power modes
Pullup/pulldown device automatically configured based on polarity of edge/level selection
A falling edge is detected when an enabled keyboard input signal is seen as a 1 (the deasserted
level) during one bus cycle and then a 0 (the asserted level) during the next cycle.
A rising edge is detected when the input signal is seen as a 0 during one bus cycle and then a 1
during the next cycle.
MC68HC908GZ60 • MC68HC908GZ48 • MC68HC908GZ32 Data Sheet, Rev. 6
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