P40 To P47 (Port 4); P120 To P123 (Port 12); P130 (Port 13); Reset - NEC 78K0S/KB1+ User Manual

(d) TO00
This pin outputs a signal from 16-bit timer/event counter 00.

2.2.4 P40 to P47 (Port 4)

P40 to P47 constitute an 8-bit I/O port, port 4. In addition to I/O port pins, P41 to P44 also have functions to output
a timer signal, input external interrupt request signals, and input/output the data of the serial interface.
These pins can be set to the following operation modes in 1-bit units.
(1) Port mode
P40 to P47 function as an 8-bit I/O port. Each bit of this port can be set to the input or output mode by using
port mode register 4 (PM4). In addition, an on-chip pull-up resistor can be connected to the port by using pull-
up resistor option register 4 (PU4).
(2) Control mode
P41 to 44 function to output a signal from an internal timer, input external interrupt request signals, and
input/output data of the serial interface.
(a) INTP1 and INTP3
These are external interrupt request input pins for which the valid edge (rising edge, falling edge, or both
rising and falling edges) can be specified.
(b) TOH1
This is the output pin of 8-bit timer H1.
(c) TxD6
This pin outputs serial data from the asynchronous serial interface.
(d) RxD6
This pin inputs serial data to the asynchronous serial interface.

2.2.5 P120 to P123 (Port 12)

P120 to P123 constitute a 4-bit I/O port, port 12.
Each bit of this port can be set to the input or output mode by using port mode register 12 (PM12). An on-chip pull-
up resistor can be connected to P120 and P123 by using pull-up resistor option register 12 (PU12).
P121 and P122 also function as the X1 and X2, respectively. For settings of alternate function, refer to CHAPTER
18 OPTION BYTE.
Caution The P121/X1 and P122/X2 pins are pulled down during reset.

2.2.6 P130 (Port 13)

This is a 1-bit output-only port.

2.2.7 RESET

This pin inputs an active-low system reset signal. When the power is turned on, this is the reset function,
regardless of the option byte setting.
CHAPTER 2 PIN FUNCTIONS
User's Manual U17446EJ3V1UD
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