UPD784938 Datasheet, PDF (126/733 Pages) NEC – 16-Bit Single-Chip Microcontrollers

CHAPTER 6 PORT FUNCTIONS
6.3 Port 1
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 programmable pull-up resistor. This port has direct LED drive capability.
In addition to their input/output port function, P10 to P14 also have an alternate function as serial interface pins. The operation
mode can be specified bit-wise by setting the port 1 mode control register (PMC1), as shown in Table 6-3. The level of any pin
can be read and tested at any time irrespective of the alternate-function operation.
When RESET is input, port 1 is set as an input port (output high-impedance state), and the output latch contents are undefined.
Table 6-3. Port 1 Operation Modes
Pin Name
P10, P11
P12
P13
P14
P15 to P17
Port Mode
I/O port
Control Signal I/O Mode
—
ASCK2 I/O/SCK2 I/O
RxD2 input/SI2 input
TxD2 output/SO2 output
—
Operation to Operate Control Pin
—
Setting PMC12 bit of PMC1 to 1
Setting PMC13 bit of PMC1 to 1
Setting PMC14 bit of PMC1 to 1
—
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Preliminary User’s Manual U13987EJ1V0UM00