8

µPD66P04B

Data Sheet U13596EJ2V1DS00

1.4 Dealing with Unused Pins

The following connections are recommended for unused pins in the normal operation mode.

Table 1-1. Connections for Unused Pins

Pin

Connection

Inside the microcontroller

Outside the microcontroller

KI/O

INPUT mode

—

Open

OUTPUT mode

High-level output

REM

—

S1/LED

OUTPUT mode (LED) setting

S0

OFF mode setting

Directly connected to GND

KI

—

RESETNote

Built-in POC circuit

Open

Note If the circuit is an applied one requiring high reliability, be sure to design it in such a manner that the RESET

signal is entered externally.

Caution The I/O mode and the terminal output level are recommended to be fixed by setting them

repeatedly in each loop of the program.

1.5 Notes on Using KI Pin at Reset

In order to prevent malfunction, do not input a high level signal to pins KI0 to KI3 (leaving these pins open is

possible, however, when these pins are left open, do not disconnect any connected pull-down resistors) when reset

is released (when RESET pin changes from low level to high level, or POC is released due to supply voltage startup).