mc68hc08ln56 Freescale Semiconductor, Inc, mc68hc08ln56 Datasheet - Page 86

• Manufacturer Part Number: mc68hc08ln56
• Description: M68hc08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

External Interrupt Module (IRQ)
The vector fetch or software clear can occur before or after the interrupt pin returns to logic one. As long
as the pin is low, the interrupt request remains pending. A reset will clear the latch and the MODEx control
bit, thereby clearing the interrupt even if the pin stays low.
When set, the IMASK1 and IMASK2 bits in the ISCR mask all external interrupt requests. A latched
interrupt request is not presented to the interrupt priority logic unless the corresponding IMASK bit is clear.
86
IRQ Status/Control Register
IRQ1/V
Register Name
IRQ2
PP
DECODER
DECODER
VECTOR
VECTOR
RESET
FETCH
RESET
FETCH
ACK1
ACK2
MC68HC08LN56 • MC68HC708LN56 General Release Specification, Rev. 2.1
(ISCR)
IRQF2
Bit 7
Figure 8-1. IRQ Module Block Diagram
Figure 8-2. IRQ I/O Register Summary
V
V
MODE1
MODE2
DD
DD
ACK2
D
D
CK
CK
6
IRQ1
IRQ2
CLR
CLR
FF
FF
Q
Q
IMASK2
5
MODE2
4
IMASK1
IMASK2
IRQF1
3
SYNCHRO-
SYNCHRO-
VOLTAGE
DETECT
NIZER
NIZER
HIGH
ACK1
2
IMASK1
1
IRQ1F
IRQ2F
MODE1
Freescale Semiconductor
Bit 0
$0032
Addr.
TO CPU FOR
BIL/BIH
INSTRUCTIONS
IRQ1
INTERRUPT
REQUEST
TO MODE
SELECT
LOGIC
IRQ2
INTERRUPT
REQUEST