CHAPTER 2 PIN FUNCTIONS
User's Manual U11919EJ3V0UM00
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2.2 Description of Pin Functions
2.2.1 P00 to P07 (Port 0)
These pins constitute an 8-bit I/O port and 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 on-chip pull-up resistor can be used in the
pull-up resistor option register (PUO).
This port can drive LEDs directly.
2.2.2 P10 to P17 (Port 1)
These pins constitute an 8-bit I/O port. Can be set in the input or output port mode in 1-bit units by using port
mode register 1 (PM1). When these pins are used as an input port, an on-chip pull-up resistor can be used in the
pull-up resistor option register (PUO).
This port can drive LEDs directly.
2.2.3 P20 to P22 (Port 2)
These pins constitute a 3-bit I/O port. In addition, these pins provide the function to input/output the data and
clock of the serial interface.
This port can drive LEDs directly.
Port 2 can be specified in the following operation modes in bit-wise.
(1)
Port mode
In this mode, port 2 functions as a 3-bit I/O port. Port 2 can be set in the input or output mode in 1-bit units
by using the port mode register 2 (PM2). When the port is used as an input port, an on-chip pull-up resistor
can be used in the pull-up resistor option register (PUO).
(2)
Control mode
In this mode, port 2 functions as the data input/output and the clock input/output of the serial interface.
(a) SI0, SO0
These are the serial data I/O pins of the serial interface.
(b) SCK0
This is the serial clock I/O pin of the serial interface.
(c) RxD, TxD
These are the serial data I/O pins of asynchronous serial interface.
(d) ASCK
This is the serial clock input pin of asynchronous serial interface.
Caution
When using port 2 as serial interface pins, the input/output mode and output latch must
be set according to the functions to be used. For details of the setting, see Table 9-2.
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