Datasheet

Keyboard Interrupt Module (KBI)
Functional Description
MC68HC908QY4•MC68HC908QT4•MC68HC908QY2•MC68HC908QT2•MC68HC908QY1•MC68HC908QT1
MOTOROLA Keyboard Interrupt Module (KBI) 179
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14.4 Functional Description
Figure 14-2. Keyboard Interrupt Block Diagram
Writing to the KBIE0–KBIE5 bits in the keyboard interrupt enable register
(KBIER) independently enables or disables each port A pin as a
keyboard interrupt pin. Enabling a keyboard interrupt pin in port A also
enables its internal pullup device irrespective of PTAPUEx bits in the
port A input pullup enable register (see 12.3.3 Port A Input Pullup
Enable Register). A logic 0 applied to an enabled keyboard interrupt pin
latches a keyboard interrupt request.
Writing the AWUIE bit in the keyboard interrupt enable register enables
or disables the auto wake-up interrupt input (see Figure 14-5). A logic 1
applied to the AWUIREQ input with auto wake-up interrupt request
enabled, latches a keyboard interrupt request.
KBIE0
KBIE5
.
.
.
DQ
CK
CLR
V
DD
MODEK
IMASKK
KEYBOARD
INTERRUPT FF
VECTOR FETCH
DECODER
ACKK
INTERNAL BUS
RESET
KBI5
KBI0
SYNCHRONIZER
KEYF
KEYBOARD
INTERRUPT
REQUEST
TO PULLUP ENABLE
AWUIREQ
(1)
TO PULLUP ENABLE
1. For AWUGEN logic refer to Figure 14-5.