Hitachi H8S/2378, H8S/2378R Series Hardware Manual page 3

General Precautions on the Handling of Products
1. Treatment of NC Pins
Note: Do not connect anything to the NC pins.
The NC (not connected) pins are not connected to any of the internal circuitry; they are
used as test pins or to reduce noise. If something is connected to the NC pins, the
operation of the LSI is not guaranteed.
2. Treatment of Unused Input Pins
Note: Fix all unused input pins to high or low level.
Generally, the input pins of CMOS products are high-impedance input pins. If unused pins
are in their open states, intermediate levels are induced by noise in the vicinity, a pass-
through current flows internally, and a malfunction may occur.
3. Processing before Initialization
Note: When power is first supplied, the product's state is undefined. The states of internal
circuits are undefined until full power is supplied throughout the chip and a low level is
input on the reset pin. During the period where the states are undefined, the register
settings and the output state of each pin are also undefined. Design your system so that it
does not malfunction because of processing while it is in this undefined state. For those
products which have a reset function, reset the LSI immediately after the power supply has
been turned on.
4. Prohibition of access to undefined or reserved address
Note: Access to undefined or reserved addresses is prohibited.
The undefined or reserved addresses may be used to expand functions, or test registers
may have been be allocated to these address. Do not access these registers: the system's
operation is not guaranteed if they are accessed.
Rev. 1.0, 09/01, page iii of xliv