s908ab32ag0cfue Freescale Semiconductor, Inc, s908ab32ag0cfue Datasheet - Page 343

• Manufacturer Part Number: s908ab32ag0cfue
• Description: M68hc08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

18.5 IRQ Status and Control Register (ISCR)
MC68HC908AB32
Freescale Semiconductor
—
Rev. 1.1
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
0 = IRQ interrupt requests on falling edges only
Shows the state of the IRQ flag
Clears the IRQ latch
Masks IRQ interrupt request
Controls triggering sensitivity of the IRQ interrupt pin
Figure 18-3. IRQ Status and Control Register (ISCR)
$001A
Bit 7
0
0
External Interrupt (IRQ)
= Unimplemented
6
0
0
5
0
0
4
0
0
IRQF
3
0
ACK
2
0
0
External Interrupt (IRQ)
IMASK
1
0
Technical Data
MODE
Bit 0
0
343