mc68hc908jb8 Freescale Semiconductor, Inc, mc68hc908jb8 Datasheet - Page 224

• Manufacturer Part Number: mc68hc908jb8
• Description: M68hc08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

External Interrupt (IRQ)
13.8 IRQ Status and Control Register
Technical Data
224
Address:
The IRQ status and control register (ISCR) controls and monitors
operation of the IRQ module. The ISCR has the following functions:
IRQF — IRQ Flag
ACK — IRQ Interrupt Request Acknowledge Bit
IMASK — IRQ Interrupt Mask Bit
MODE — IRQ Edge/Level Select Bit
Reset:
Read:
Write:
•
•
•
•
This read-only status bit is high when the IRQ interrupt is pending.
Writing a logic 1 to this write-only bit clears the IRQ latch. ACK always
reads as logic 0. Reset clears ACK.
Writing a logic 1 to this read/write bit disables IRQ interrupt requests.
Reset clears IMASK.
This read/write bit controls the triggering sensitivity of the IRQ pin.
Reset clears MODE.
1 = IRQ interrupt pending
0 = IRQ interrupt not pending
1 = IRQ interrupt requests disabled
0 = IRQ interrupt requests enabled
1 = IRQ interrupt requests on falling edges and low levels
Shows the state of the IRQ flag
Clears the IRQ latch
Masks IRQ interrupt request
Controls triggering sensitivity of the IRQ pin
Figure 13-3. IRQ Status and Control Register (ISCR)
$001E
Bit 7
0
0
External Interrupt (IRQ)
= Unimplemented
6
0
0
MC68HC908JB8•MC68HC08JB8•MC68HC08JT8 — Rev. 2.3
5
0
0
4
0
0
IRQF
3
0
ACK
Freescale Semiconductor
0
0
2
IMASK
0
1
MODE
Bit 0
0