MC68HC08GZ32 Datasheet, PDF (92/320 Pages) Freescale Semiconductor, Inc – Microcontrollers

External Interrupt (IRQ)
RESET
ACK
VECTOR
FETCH
DECODER
V_DD
INTERNAL
PULLUP
DEVICE
IRQ
V_DD
CLR
D
Q
CK
SYNCHRONIZER
IMASK
TO CPU FOR
BIL/BIH
INSTRUCTIONS
IRQF
IRQ
INTERRUPT
REQUEST
MODE
HIGH
VOLTAGE
DETECT
Figure 8-1. IRQ Module Block Diagram
TO MODE
SELECT
LOGIC
The vector fetch or software clear may occur before or after the interrupt pin returns to logic 1. As long as
the pin is low, the interrupt request remains pending. A reset will clear the latch and the MODE control bit,
thereby clearing the interrupt even if the pin stays low.
When set, the IMASK bit in the INTSCR masks all external interrupt requests. A latched interrupt request
is not presented to the interrupt priority logic unless the IMASK bit is clear.
NOTE
The interrupt mask (I) in the condition code register (CCR) masks all
interrupt requests, including external interrupt requests.
Addr.
$001D
Register Name
Bit 7
6
5
IRQ Status and Control ^Read:
0
0
0
Register (INTSCR) Write:
See page 94. _Reset:
0
0
0
= Unimplemented
4
3
0
IRQF
0
0
Figure 8-2. IRQ I/O Register Summary
2
1
Bit 0
0
IMASK MODE
ACK
0
0
0
8.4 IRQ Pin
A falling edge on the IRQ pin can latch an interrupt request into the IRQ latch. A vector fetch, software
clear, or reset clears the IRQ latch.
MC68HC08GZ32 Data Sheet, Rev. 3
92
Freescale Semiconductor