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CHAPTER 2 PIN FUNCTIONS
(a) Port mode
Each port pin set in the port mode by the port 3 mode control register (PMC3) can be set in the input or output
mode by the port 3 mode register (PM3).
(b) Control signal I/O mode
Each pin of port 3 can be set in the control mode in 1-bit units by using the port 3 mode control register (PMC3).
(i) TO10, TO11 (Timer Output)
These are timer output pins of timer 1.
(ii) RxD, RxD2 (Receive Data)
These are serial data input pins of the asynchronous serial interface.
(iii) TxD, TxD2 (Transmit data)
These are serial data output pins of the asynchronous serial interface.
(iv) SI1, SI2 (Serial Input)
These are serial data input pins of the 3-wire serial I/O.
(v) SO1, SO2 (Serial Output)
These are serial data output pins of the 3-wire serial I/O.
(vi) ASCK, ASCK2 (Asynchronous Serial Clock)
These are external baud rate clock input pins.
(vii) SCK1, SCK2 (Serial Clock)
These are serial clock I/O pins of the 3-wire serial I/O.
(5) P40 through P47 (Port 4) ... 3-state I/O
Port 4 is an 8-bit I/O port with an output latch. This port can be set in the input or output mode in 1-bit units by using
port 4 mode register (PM4). Each pin is provided with a software programmable pull-up resistor.
Port 4 functions as the low-order multiplexed address/data bus (AD0 through AD7) if so specified by memory
expansion mode register (MM) when an external memory or I/O is connected, in addition to the I/O port function.
When RESET is input, this port is set in the input mode (output high-impedance status), and the contents of the
output latch are undefined.
(6) P50 through P57 (Port 5) ... 3-state I/O
Port 5 is an 8-bit I/O port with an output latch. This port can be set in the input or output mode in 1-bit units by using
port 5 mode register (PM5). Each pin is provided with a software programmable pull-up resistor.
This port functions as follows if so specified by memory expansion mode register (MM) when an external memory
or I/O is connected:
When external 8-bit bus is specified
As the high-order address bus (AD8 through AD15)
When external 16-bit bus is specified
As the high-order multiplexed address/data bus (AD8 through AD15).
When RESET is input, this port is set in the input mode (output high-impedance status), and the contents of the
output latch are undefined.