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CHAPTER 3 PIN FUNCTIONS (
μ
PD78018F SUBSERIES)
3.2.4 P30-P37 (Port3)
These pins constitute an 8-bit I/O port, port 3. In addition, they also functions as timer I/O, clock output, and buzzer
output pins.
Port 3 can be set in the following operation modes in 1-bit units.
(1) Port mode
In this mode, port 3 functions as 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 3 (PM3). 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, the pins of port 3 can be used as timer I/O, clock output, and buzzer output pins.
(a) TI1, TI2
These pins input an external count clock to the 8-bit timer/event counter.
(b) TO0-TO2
Timer output pins.
(c) PCL
Clock output pin.
(d) BUZ
Buzzer output pin.
3.2.5 P40-P47 (Port4)
These pins form an 8-bit I/O port, port 4. In addition, they also form an address/data bus.
When the falling edge of these pins is detected, the test input flag (KRIF) can be set to 1.
This port can be set in the following operation modes in 8-bit units.
(1) Port mode
In this mode, P40 through P47 function as an 8-bit I/O port which can be set in the input or output mode in
8-bit units by using the memory extension mode register (MM). 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, P40 through P47 function as the low-order address/data bus pins (AD0-AD7) in the external
memory extension mode. The pins used as address/data bus pins are automatically disconnected from the
internal pull-up resistor.