mc68hc908gr8vp Freescale Semiconductor, Inc, mc68hc908gr8vp Datasheet - Page 121

• Manufacturer Part Number: mc68hc908gr8vp
• Description: M68hc08 Microcontrollers Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

Chapter 13
Keyboard Interrupt (KBI)
13.1 Introduction
The keyboard interrupt module (KBI) provides four independently maskable external interrupts which are
accessible via PTA0–PTA3. When a port pin is enabled for keyboard interrupt function, an internal pullup
device is also enabled on the pin.
13.2 Features
13.3 Functional Description
Writing to the KBIE3–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 device. A low level applied to an enabled keyboard interrupt pin latches a keyboard
interrupt request.
Freescale Semiconductor
TO PULLUP
TO PULLUP
•
•
•
•
•
KBD0
KBD3
ENABLE
ENABLE
Four 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
Exit from low-power modes
I/O (input/output) port bit(s) software configurable with pullup device(s) if configured as input port
bit(s)
KB0IE
KB3IE
.
.
.
Figure 13-1. Keyboard Module Block Diagram
MC68HC908GR8 • MC68HC908GR4 Data Sheet, Rev. 7
MODEK
VDD
D
CK
CLR
Q
INTERRUPT FF
KEYBOARD
RESET
ACKK
IMASKK
VECTOR FETCH
INTERNAL BUS
DECODER
SYNCHRONIZER
KEYF
KEYBOARD
INTERRUPT
REQUEST
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