mc68hc908mr24 Freescale Semiconductor, Inc, mc68hc908mr24 Datasheet - Page 345

• Manufacturer Part Number: mc68hc908mr24
• Description: M68hc08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

MC68HC908MR24 — Rev. 4.1
Freescale Semiconductor
NOTE:
The external interrupt pins are falling-edge-triggered and are software-
configurable to be both falling-edge and low-level-triggered. The
MODE1 bit in the ISCR controls the triggering sensitivity of the IRQ pin.
When the interrupt pin is edge-triggered only, the interrupt latch remains
set until a vector fetch, software clear, or reset occurs.
When the interrupt pin is both falling-edge and low-level-triggered, the
interrupt latch remains set until both of the following occur:
The vector fetch or software clear can occur before or after the interrupt
pin returns to logic 1. As long as the pin is low, the interrupt request
remains pending.
When set, the IMASK1 bit in the ISCR masks all external interrupt
requests. A latched interrupt request is not presented to the interrupt
priority logic unless the IMASK bit is clear.
The interrupt mask (I) in the condition code register (CCR) masks all
interrupt requests, including external interrupt requests.
(See
•
•
Figure
Vector fetch, software clear, or reset
Return of the interrupt pin to logic 1
17-3.)
External Interrupt (IRQ)
External Interrupt (IRQ)
Advance Information
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