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CHAPTER 3 PIN FUNCTIONS (
μ
PD78018F SUBSERIES)
3.2 Description of Pin Functions
3.2.1 P00-P04 (Port0)
These pins constitute a 5-bit I/O port, port 0. In addition, these pins are also used to input external interrupt request
signals, an external count clock to timer, a capture trigger signal, and to connect a crystal resonator for subsystem
clock oscillation.
Port 0 can be specified in the following operation modes in 1-bit units.
(1) Port mode
In the port mode, P00 and P04 function as input port lines, and P01 through P03 function as I/O port lines.
P01 through P03 can be set in the input or output port mode in 1-bit units by using port mode register 0 (PM0).
When these pins are used as an input port, an internal pull-up resistor can be used if so specified by the pull-
up resistor option register (PUO).
(2) Control mode
In this mode, P00 through P04 are used to input external interrupt requests, an external count clock to timer,
and to connect a crystal resonator for subsystem clock oscillation.
(a) INTP0-INTP3
INTP0 through INTP2 are external interrupt request input pins for which valid edge can be specified
(rising edge, falling edge, and both rising and falling edges). INTP0 also functions as the capture
trigger input pin of the 16-bit timer/event counter when a valid edge is input. INTP3 is a falling edge-
triggered external interrupt request input pin.
(b) TI0
External count clock input pin of the 16-bit timer/event counter
(c) XT1
Subsystem clock oscillation crystal connecting pin
3.2.2 P10-P17 (Port1)
These pins form an 8-bit I/O port, port 1. These pins also serve as the analog input pins of the A/D converter.
They can be set in the following operation modes in 1-bit units.
(1) Port mode
In this mode, P10 through P17 constitute an 8-bit I/O port which can be set in the input or output mode in 1-
bit units by using the port mode register 1 (PM1). When used as an input port, an internal pull-up resistor
can be used if so specified by the pull-up resistor option register (PUO).
(2) Control mode
In this mode, P10 through P17 function as the analog input pins (ANI0-ANI7) of the A/D converter. When these
pins are specified to serve as analog input pins, the internal pull-up resistor is automatically disconnected.