UPD784938 Datasheet, PDF (55/733 Pages) NEC – 16-Bit Single-Chip Microcontrollers

CHAPTER 2 PIN FUNCTIONS
2.2 Pin Functions
2.2.1 Normal operation mode
(1) P00 to P07 (Port 0) ... 3-state input/output
Port 0 is an 8-bit input/output port with an output latch, and has direct transistor drive capability. Input/output can be specified
in 1-bit units by setting the port 0 mode register (PM0). Each pin incorporates a software programmable pull-up resistor.
P00 to P03 and P04 to P07 can output the port 0 buffer register (P0L, P0H) contents at any time interval as 4-bit or 8-bit
real-time output port. The real-time output port control register (RTPC) is used to select whether this port is used as a normal
output port or a real-time output port.
When RESET is input, port 0 is set as an input port (output high-impedance state), and the output latch contents become
undefined.
(2) P10 to P17 (Port 1) ... 3-state input/output
Port 1 is an 8-bit input/output port with an output latch. Input/output can be specified in 1-bit units by setting the port 1 mode
register (PM1). Each pin incorporates a software programmable pull-up resistor. This port has direct LED drive capability.
Pins P12 to P14 can also be made to function as serial input/output pins by setting the port 1 mode control register (PMC1).
When RESET is input, port 1 is set as an input port (output high-impedance state), and the output latch contents are
undefined.
Table 2-1. Port 1 Operation Modes
Pin Name
P10
P11
P12
P13
P14
P15 to P17
Port Mode
Input/output port
Control Signal Input/Output Mode
Operation to Operate as Control Pin
—
—
—
—
ASCK2/SCK2 input/output
Set (to 1) PMC12 bit of PMC1
RxD2/SI2 input
Set (to 1) PMC13 bit of PMC1
TxD2/SO2 output
Set (to 1) PMC14 bit of PMC1
—
—
(a) Port mode
P12 to P14 operate as port mode pins when the relevant bits of the port 1 mode control (PMC1) register are cleared
(0), and P10 and P11 and P15 to P17 always operate as port mode pins. Input/output can be specified in 1-bit units
by setting the port 1 mode register (PM1).
(b) Control signal input/output mode
P12 to P14 can be set as control pins in 1-bit units by setting the port 1 mode control (PMC1) register.
(i) ASCK2/SCK2
ASCK2 is the asynchronous serial interface baud rate clock input pin.
SCK2 is the serial clock input/output pin (in 3-wire serial I/O2 mode).
(ii) RxD2/SI2
RxD2 is the asynchronous serial interface serial data input pin.
SI2 is the serial data input pin (in 3-wire serial I/O2 mode).
(iii) TxD2/SO2
TxD2 is the asynchronous serial interface serial data output pin.
SO2 is the serial data output pin (in 3-wire serial I/O2 mode).
Preliminary User’s Manual U13987EJ1V0UM00
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