mc68hc05j5ap Freescale Semiconductor, Inc, mc68hc05j5ap Datasheet - Page 31

• Manufacturer Part Number: mc68hc05j5ap
• Description: General Description The Mc68hc05j5a Is A Member Of The Low-cost High-performance M68hc05 Family Of 8-bit Microcontroller Units Mcus . The M68hc05 Family Is Based On The Customer-speci Ed Integrated Circuit Design Strategy. All Mcus In The Family
• Manufacturer: Freescale Semiconductor, Inc

4.5.1 IRQ CONTROL/STATUS REGISTER (ICSR) $0A
REV 2.1
$000A
ICSR
reset
The IRQ interrupt function is controlled by the ICSR located at $000A. All unused
bits in the ICSR will read as logic zeros. The IRQF, IRQF1, IRQE1 bits are cleared
and IRQE bit is set by reset.
IRQR 1 - PA7 Interrupt Acknowledge
IRQR - IRQ Interrupt Acknowledge
IRQF1 - PA7 Interrupt Request Flag
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The IRQR1 acknowledge bit clears an IRQ interrupt triggered by a falling edge
on PA7 by clearing the IRQ1 latch. The IRQR1 acknowledge bit will always read
as a logic zero.
The IRQR acknowledge bit clears an IRQ interrupt by clearing the IRQ latch.
The IRQR acknowledge bit will always read as a logic zero.
Writing to the IRQF1 flag bit will have no effect on it. If the additional setting of
IRQF1 flag bit is not cleared in the IRQ service routine and the IRQE1 enable
bit remains set the CPU will re-enter the IRQ interrupt sequence continuously
until either the IRQF1 flag bit or the IRQE1 enable bit is cleared. The IRQF1
latch is cleared by reset.
RESERVED FOR TEST
1 = Writing a logic one to the IRQR1 acknowledge bit will clear the IRQ1
0 = Writing a logic zero to the IRQR1 acknowledge bit will have no effect
1 = Writing a logic one to the IRQR acknowledge bit will clear the IRQ
0 = Writing a logic zero to the IRQR acknowledge bit will have no effect
1 = Indicates that an IRQ request triggered by a falling edge on PA7 is
0 = Indicates that no IRQ request triggered by a falling edge on PA7 is
IRQE
1
7
latch.
on the IRQ1 latch.
latch.
on the IRQ latch.
pending.
pending. The IRQF1 flag bit can ONLY be cleared by writing a logic
one to the IRQR1 acknowledge bit. Doing so before exiting the
service routine will mask out additional occurrences of the IRQF1.
Figure 4-3. IRQ Status & Control Register
IRQE1
Freescale Semiconductor, Inc.
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6
For More Information On This Product,
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Go to: www.freescale.com
0
5
0
INTERRUPTS
July 16, 1999
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0
4
0
UNIMPLEMENTED
IRQF
0
3
GENERAL RELEASE SPECIFICATION
IRQF1
0
2
IRQR
0
1
0
IRQR1
0
0
0
4-5