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4.4
Port2
Port 2 is a general-purpose I/O port that also serves as a peripheral resource I/O pin.
Use port 2 by switching between the resource pin and the general-purpose I/O port.
The configuration, pin assignment, block diagram of the pins, and registers for port 2
are shown below.
I Configuration of Port 2
Port 2 consists of the following four elements:
• General-purpose I/O port, resource I/O pin (P20/TIN0 to P27/INT7)
• Port 2 data register (PDR2)
• Port 2 direction register (DDR2)
• High address control register (HACR)
I Pin Assignment of Port 2
• The pin is used either a resource pin or a general-purpose I/O pin
• Since the port serves as resource pin, when used as a resource pin the port cannot be used as general-
purpose I/O port.
• When using port 2 as the input pin of the resource, set the pin corresponding to the resource in the
DDR2 as an input port.
• When using the port as the output of the resource, set the output of the corresponding resource to
enabled.Port 2 functions as the output pin of the resource regardless of the settings of the DDR2.
CHAPTER 4 I/O PORT
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