MC68HC08AZ60 Datasheet, PDF (166/452 Pages) Motorola, Inc – Advance Information

Freescale Semiconductor, Inc.
External Interrupt Module (IRQ)
Functional Description
A logic 0 applied to the external interrupt pin can latch a CPU interrupt
request. Figure 1 shows the structure of the IRQ module.
Interrupt signals on the IRQ pin are latched into the IRQ latch. An
interrupt latch remains set until one of the following actions occurs:
• 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
IRQ latch.
• Reset — A reset automatically clears both interrupt latches.
ACK1
VECTOR
FETCH
DECODER
IRQ
V_DD
CLR
D
Q
CK
IRQ
LATCH
SYNCHRO-
NIZER
IMASK1
MODE1
HIGH
VOLTAGE
DETECT
Figure 1. IRQ Block Diagram
TO CPU FOR
BIL/BIH
INSTRUCTIONS
IRQF
IRQ
INTERRUPT
REQUEST
TO MODE
SELECT
LOGIC
MC68HC08AZ60 — Rev 1.0
166
External Interrupt Module (IRQ)
For More Information On This Product,
Go to: www.freescale.com
2-irq
MOTOROLA