
CHAPTER 2 PIN FUNCTIONS
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(a) Port mode
Each port specified as port mode by the port 3 mode control (PMC3) register can be specified as input/output bit-wise
by means of the port 3 mode register (PM3).
(b) Control signal input/output mode
Pins can be set as control pins bit-wise by setting the port 3 mode control (PMC3) register.
(i)
RxD (Receive Data)/SI1 (Serial Input 1)
RxD is the asynchronous serial interface serial data input pin.
SI1 is the serial data input pin (in 3-wire serial I/O1 mode).
(ii)
TxD (Transmit Data)/SO1 (Serial Output 1)
TxD is the asynchronous serial interface serial data output pin.
SO1 is the serial data output pin (in 3-wire serial I/O1 mode).
(iii) SCK0 (Serial Clock 0)/SCL (Serial Clock)
SCK0 is the clocked serial interface serial clock input/output pin (in 3-wire serial I/O 0 mode).
SCL is the synchronous serial interface serial clock input/output pin (in 2-wire serial I/O mode/I
2
C bus mode
Note
).
Note
μ
PD784038Y Subseries only
(iv) SO0 (Serial Output 0)/SDA (Serial Data)
SO0 is the serial data output pin (in 3-wire serial I/O 0 mode), and SDA is the serial data input/output pin (in 2-
wire serial I/O mode/I
2
C bus mode
Note
).
Note
μ
PD784038Y Subseries only
(v)
TO0 to TO3 (Timer Output)
The timer output pins.
(5) P40 to P47 (Port 4) ... 3-state input/output
Port 4 is an 8-bit input/output port with an output latch. Input/output can be specified bit-wise by means of the port 4 mode
register (PM4). Each pin incorporates a software programmable pull-up resistor. This port has direct LED drive capability.
Port 4 also functions as the time division address/data bus (AD0 to AD7) by the memory extension mode register (MM) when
external memory or I/Os are extended.
With the
μ
PD784031, P40 to P47 cannot be used as port pins. These pins function only as the time division address/data
bus pins (AD0 to AD7).
When RESET is input, port 4 is set as an input port (output high-impedance state), and the output latch contents are
undefined.
(6) P50 to P57 (Port 5) ... 3-state input/output
Port 5 is an 8-bit input/output port with an output latch. Input/output can be specified bit-wise by means of the port 5 mode
register (PM5). Each pin incorporates a software programmable pull-up resistor. This port has direct LED drive capability.
In addition, P50 to P57 can be selected by means of the memory extension mode register (MM) in 2-bit units as pins that
function as the address bus (A8 to A15) when external memory or I/Os are extended.
With the
μ
PD784031, P50 to P57 cannot be used as port pins. These pins function only as the address bus pins (A8 to
A15).
When RESET is input, port 5 is set as an input port (output high-impedance state), and the output latch contents are
undefined.