mc68hc05j1a Freescale Semiconductor, Inc, mc68hc05j1a Datasheet - Page 43

• Manufacturer Part Number: mc68hc05j1a
• Description: M68hc05 Microcontrollers Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

MC68HC05J1A — Rev. 3.0
EXTERNAL INTERRUPTS
PA0
IRQ
PA3
PA2
PA1
(MASK OPTION)
ENABLED
PORT A
External interrupt triggering sensitivity is a mask option. The IRQ pin can
be negative edge-triggered only or negative edge- and low
level-triggered.
With the mask option for an edge- and level-sensitive external interrupt
trigger, a falling edge or a low level on the IRQ pin latches an external
interrupt request. Edge- and level-sensitive triggering allows the use of
multiple wired-OR external interrupt sources. An external interrupt
request is latched as long as any source is holding the IRQ pin low.
With the mask option for an edge-sensitive only external interrupt trigger,
a falling edge on the IRQ pin latches an external interrupt request. A
subsequent external interrupt request can be latched only after the
voltage level on the IRQ pin returns to logic 1 and then falls again to
logic 0.
Freescale Semiconductor, Inc.
Figure 4-1. External Interrupt Logic
For More Information On This Product,
IRQ VECTOR FETCH
INTERNAL DATA BUS
Go to: www.freescale.com
LEVEL-SENSITIVE TRIGGER
RST
Interrupts
V
DD
(MASK OPTION)
LATCH
IRQ
R
IRQ STATUS AND CONTROL REGISTER
TO BIH & BIL
INSTRUCTION
PROCESSING
EXTERNAL
INTERRUPT
REQUEST
Interrupt Sources
Technical Data
Interrupts