MC68HC908KX2 MOTOROLA [Motorola, Inc], MC68HC908KX2 Datasheet - Page 166

• Manufacturer Part Number: MC68HC908KX2
• Description: Microcontrollers
• Manufacturer: MOTOROLA [Motorola, Inc]

External Interrupt (IRQ)
12.4 Functional Description
Technical Data
166
IRQ1
DECODER
VECTOR
V
FETCH
''
INTERNAL
PULLUP
DEVICE
ACK1
A logic 0 applied to the external interrupt pin can latch a central
processor unit (CPU) interrupt request.
of the IRQ module.
Interrupt signals on the IRQ1 pin are latched into the IRQ1 latch. An
interrupt latch remains set until one of these actions occurs:
The external interrupt pin is falling-edge triggered and is software-
configurable to be both falling-edge and low-level triggered. The MODE1
bit in the ISCR controls the triggering sensitivity of the IRQ1 pin.
•
•
•
V
MODE1
''
Vector fetch — A vector fetch automatically generates an interrupt
acknowledge signal that clears the latch that caused the vector
fetch.
Software clear — Software can clear an interrupt latch by writing
to the appropriate acknowledge bit in the interrupt status and
control register (ISCR). Writing a logic 1 to the ACK1 bit clears the
IRQ1 latch.
Reset — A reset automatically clears the interrupt latch.
Figure 12-1. IRQ Block Diagram
D
CK
LATCH
IRQ1
CLR
Q
External Interrupt (IRQ)
MC68HC908KX8 • MC68HC908KX2 • MC68HC08KX8 — Rev. 1.0
IMASK1
SYNCHRONIZER
VOLTAGE
DETECT
HIGH
Figure 12-1
shows the structure
IRQF1
TO CPU FOR
BIL/BIH
INSTRUCTIONS
IRQ1
INTERRUPT
REQUEST
TO MODE
SELECT
LOGIC
MOTOROLA