mc68hsc705j1a Freescale Semiconductor, Inc, mc68hsc705j1a Datasheet - Page 106

• Manufacturer Part Number: mc68hsc705j1a
• Description: M68hc05 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

External Interrupt Module (IRQ)
8.4 IRQ Status and Control Register
Technical Data
Address:
The IRQ status and control register (ISCR) controls and monitors
operation of the IRQ module. All unused bits in the ISCR read as
logic 0s. The IRQF bit is cleared and the IRQE bit is set by reset.
IRQR — Interrupt Request Reset Bit
IRQF — External Interrupt Request Flag
IRQE — External Interrupt Request Enable Bit
The STOP and WAIT instructions set the IRQE bit so that an external
interrupt can bring the MCU out of these low-power modes. In addition,
reset sets the I bit which masks all interrupt sources.
Reset:
Read:
Write:
This write-only bit clears the external interrupt request flag.
The external interrupt request flag is a clearable, read-only bit that is
set when an external interrupt request is pending. Reset clears the
IRQF bit.
This read/write bit enables external interrupts. Reset sets the IRQE
bit.
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1 = Clears external interrupt and IRQF bit
0 = No effect on external interrupt and IRQF bit
1 = External interrupt request pending
0 = No external interrupt request pending
1 = External interrupt requests enabled
0 = External interrupt requests disabled
Figure 8-3. IRQ Status and Control Register (ISCR)
$000A
IRQE
Bit 7
1
External Interrupt Module (IRQ)
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= Unimplemented
6
0
0
5
0
0
R
4
0
0
R = Reserved
IRQF
3
0
MC68HC705J1A — Rev. 4.0
2
0
0
IRQR
1
0
0
Bit 0
0
0