MC68HC908LJ24 Datasheet, PDF (405/464 Pages) Motorola, Inc – Microcontrollers

External Interrupt (IRQ)
IRQ Module During Break Interrupts
19.5 IRQ Module During Break Interrupts
The system integration module (SIM) controls whether the IRQ latch can
be cleared during the break state. The BCFE bit in the break flag control
register (BFCR) enables software to clear the latches during the break
state. (See Section 23. Break Module (BRK).)
To allow software to clear the IRQ latch during a break interrupt, write a
logic 1 to the BCFE bit. If a latch is cleared during the break state, it
remains cleared when the MCU exits the break state.
To protect the latches during the break state, write a logic 0 to the BCFE
bit. With BCFE at logic 0 (its default state), writing to the ACK bit in the
IRQ status and control register during the break state has no effect on
the IRQ latch.
19.6 IRQ Status and Control Register (INTSCR)
The IRQ status and control register (INTSCR) controls and monitors
operation of the IRQ module. The INTSCR has the following functions:
• Shows the state of the IRQ flag
• Clears the IRQ latch
• Masks IRQ and interrupt request
• Controls triggering sensitivity of the IRQ interrupt pin
MC68HC908LJ24/LK24 — Rev. 2.1
Freescale Semiconductor
External Interrupt (IRQ)
Data Sheet
405