MC68HC05K1 FREESCALE [Freescale Semiconductor, Inc], MC68HC05K1 Datasheet - Page 69

• Manufacturer Part Number: MC68HC05K1
• Description: HCMOS Microcontroller Unit
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

7.3.4 Port A External Interrupts
7.3.5 Port A Logic
MC68HC05K0 • MC68HC05K1 — Rev. 2.0
NOTE:
READ $0004
WRITE $0004
WRITE $0000
READ $0000
WRITE $0010
RESET
If the mask option for port A external interrupts is selected, the PA3–PA0
pins serve as external interrupt pins in addition to the IRQ/V
External interrupts can be positive edge-triggered or positive edge- and
high level-triggered.
When testing for external interrupts, the BIH and BIL instructions test the
voltage on the IRQ/V
Therefore, BIH and BIL do not test the port A external interrupt pins.
Port A interrupts are not sensitive to the direction of the port pins. Driving
a logic 1 on PA0–PA3 while port interrupts are enabled will cause an
interrupt, even if PA0–PA3 are set to outputs.
Figure 7-4
Freescale Semiconductor, Inc.
PULLDOWNS ENABLED (ACTIVE LOW)
For More Information On This Product,
Figure 7-4. Port A I/O Circuit
DATA DIRECTION
(MASK OPTION)
PORT A DATA
REGISTER A
REGISTER A
REGISTER
shows the port A I/O logic.
PULLDOWN
BIT DDRAx
BIT PDIAx
BIT PAx
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Parallel Input/Output (I/O)
PP
pin, not the state of the internal IRQ signal.
(PINS PA3–PA0)
INTERRUPT
EXTERNAL
REQUEST
Parallel Input/Output (I/O)
100-mA
PULLDOWN
DEVICE
(PINS PA7–PA4)
CAPABILITY
8-mA SINK
PAx
Technical Data
PP
pin.
Port A