MC68HC08LT8 Datasheet, PDF (110/156 Pages) Freescale Semiconductor, Inc – Microcontrollers

External Interrupt (IRQ)
10.5 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
Address: $001E
Bit 7
Read: 0
Write:
Reset: 0
6
5
0
0
0
0
= Unimplemented
4
3
2
1
Bit 0
0
IRQF
0
IMASK MODE
ACK
0
0
0
0
0
Figure 10-3. IRQ Status and Control Register (INTSCR)
IRQF — IRQ Flag Bit
This read-only status bit is high when the IRQ interrupt is pending.
1 = IRQ interrupt pending
0 = IRQ interrupt not pending
ACK — IRQ Interrupt Request Acknowledge Bit
Writing a logic one to this write-only bit clears the IRQ latch. ACK always reads as logic zero. Reset
clears ACK.
IMASK — IRQ Interrupt Mask Bit
Writing a logic one to this read/write bit disables IRQ interrupt requests. Reset clears IMASK.
1 = IRQ interrupt requests disabled
0 = IRQ interrupt requests enabled
MODE — IRQ Edge/Level Select Bit
This read/write bit controls the triggering sensitivity of the IRQ pin. Reset clears MODE.
1 = IRQ interrupt requests on falling edges and low levels
0 = IRQ interrupt requests on falling edges only
MC68HC08LT8 Data Sheet, Rev. 1
110
Freescale Semiconductor