MC68HC908QY2 MOTOROLA [Motorola, Inc], MC68HC908QY2 Datasheet - Page 172

• Manufacturer Part Number: MC68HC908QY2
• Description: Microcontrollers
• Manufacturer: MOTOROLA [Motorola, Inc]

External Interrupt (IRQ)
13.4 Functional Description
172
MC68HC908QY4•MC68HC908QT4•MC68HC908QY2•MC68HC908QT2•MC68HC908QY1•MC68HC908QT1
IRQPUD
IRQ
DECODER
VECTOR
RESET
FETCH
ACK1
V
DD
INTERNAL
PULLUP
DEVICE
IRQ pin functionality is enabled by setting configuration register 2
(CONFIG2) IRQEN bit accordingly. A 0 disables the IRQ function and
IRQ will assume the other shared functionalities. A1 enables the IRQ
function.
A logic 0 applied to the external interrupt pin can latch a central
processur unit (CPU) interrupt request.
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:
Figure 13-1. IRQ Module Block Diagram
•
•
•
V
MODE1
DD
Vector fetch — A vector fetch automatically generates an interrupt
acknowledge signal that clears the IRQ latch.
Software clear — Software can clear the interrupt latch by writing
to the 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 the interrupt latch.
D
CK
CLR
IRQ
FF
Q
External Interrupt (IRQ)
IMASK1
SYNCHRO-
VOLTAGE
DETECT
NIZER
HIGH
Figure 13-1
IRQF1
shows the structure
MOTOROLA
TO CPU FOR
BIL/BIH
INSTRUCTIONS
IRQ
INTERRUPT
REQUEST
TO MODE
SELECT
LOGIC