User’s Manual
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PD789489 Subseries
8-Bit Single-Chip Microcontrollers
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PD789488
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PD789489
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PD78F9488
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PD78F9489
Document No. U15331EJ4V1UD00 (4th edition)
Date Published July 2005 NS CP(K)
©
Printed in Japan
[MEMO]
2
User’s Manual U15331EJ4V1UD
NOTES FOR CMOS DEVICES
1
VOLTAGE APPLICATION WAVEFORM AT INPUT PIN
Waveform distortion due to input noise or a reflected wave may cause malfunction. If the input of the
CMOS device stays in the area between V
IL
(MAX) and V
IH
(MIN) due to noise, etc., the device may
malfunction. Take care to prevent chattering noise from entering the device when the input level is fixed,
and also in the transition period when the input level passes through the area between V
IL
(MAX) and
V
IH
(MIN).
2
HANDLING OF UNUSED INPUT PINS
Unconnected CMOS device inputs can be cause of malfunction. If an input pin is unconnected, it is
possible that an internal input level may be generated due to noise, etc., causing malfunction. CMOS
devices behave differently than Bipolar or NMOS devices. Input levels of CMOS devices must be fixed
high or low by using pull-up or pull-down circuitry. Each unused pin should be connected to V
DD
or GND
via a resistor if there is a possibility that it will be an output pin. All handling related to unused pins must
be judged separately for each device and according to related specifications governing the device.
3
PRECAUTION AGAINST ESD
A strong electric field, when exposed to a MOS device, can cause destruction of the gate oxide and
ultimately degrade the device operation. Steps must be taken to stop generation of static electricity as
much as possible, and quickly dissipate it when it has occurred.
Environmental control must be
adequate. When it is dry, a humidifier should be used. It is recommended to avoid using insulators that
easily build up static electricity. Semiconductor devices must be stored and transported in an anti-static
container, static shielding bag or conductive material. All test and measurement tools including work
benches and floors should be grounded.
The operator should be grounded using a wrist strap.
Semiconductor devices must not be touched with bare hands. Similar precautions need to be taken for
PW boards with mounted semiconductor devices.
4
STATUS BEFORE INITIALIZATION
Power-on does not necessarily define the initial status of a MOS device. Immediately after the power
source is turned ON, devices with reset functions have not yet been initialized. Hence, power-on does
not guarantee output pin levels, I/O settings or contents of registers. A device is not initialized until the
reset signal is received. A reset operation must be executed immediately after power-on for devices
with reset functions.
5
POWER ON/OFF SEQUENCE
In the case of a device that uses different power supplies for the internal operation and external
interface, as a rule, switch on the external power supply after switching on the internal power supply.
When switching the power supply off, as a rule, switch off the external power supply and then the
internal power supply. Use of the reverse power on/off sequences may result in the application of an
overvoltage to the internal elements of the device, causing malfunction and degradation of internal
elements due to the passage of an abnormal current.
The correct power on/off sequence must be judged separately for each device and according to related
specifications governing the device.
6
INPUT OF SIGNAL DURING POWER OFF STATE
Do not input signals or an I/O pull-up power supply while the device is not powered. The current
injection that results from input of such a signal or I/O pull-up power supply may cause malfunction and
the abnormal current that passes in the device at this time may cause degradation of internal elements.
Input of signals during the power off state must be judged separately for each device and according to
related specifications governing the device.
User’s Manual U15331EJ4V1UD
3
EEPROM and FIP are trademarks of NEC Electronics Corporation.
Windows and Windows NT are either registered trademarks or trademarks of Microsoft Corporation in the
United States and/or other countries.
PC/AT is a trademark of International Business Machines Corporation.
HP9000 series 700 and HP-UX are trademarks of Hewlett-Packard Company.
SPARCstation is a trademark of SPARC International, Inc.
Solaris and SunOS are trademarks of Sun Microsystems, Inc.
These commodities, technology or software, must be exported in accordance
with the export administration regulations of the exporting country.
Diversion contrary to the law of that country is prohibited.
4
User’s Manual U15331EJ4V1UD
•
The information in this document is current as of July, 2005. The information is subject to change
without notice. For actual design-in, refer to the latest publications of NEC Electronics data sheets or
data books, etc., for the most up-to-date specifications of NEC Electronics products. Not all
products and/or types are available in every country. Please check with an NEC Electronics sales
representative for availability and additional information.
•
No part of this document may be copied or reproduced in any form or by any means without the prior
written consent of NEC Electronics. NEC Electronics assumes no responsibility for any errors that may
appear in this document.
•
NEC Electronics does not assume any liability for infringement of patents, copyrights or other intellectual
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or any other liability arising from the use of such products. No license, express, implied or otherwise, is
granted under any patents, copyrights or other intellectual property rights of NEC Electronics or others.
•
Descriptions of circuits, software and other related information in this document are provided for illustrative
purposes in semiconductor product operation and application examples. The incorporation of these
circuits, software and information in the design of a customer's equipment shall be done under the full
responsibility of the customer. NEC Electronics assumes no responsibility for any losses incurred by
customers or third parties arising from the use of these circuits, software and information.
•
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customers agree and acknowledge that the possibility of defects thereof cannot be eliminated entirely. To
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Electronics products, customers must incorporate sufficient safety measures in their design, such as
redundancy, fire-containment and anti-failure features.
•
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support systems and medical equipment for life support, etc.
The quality grade of NEC Electronics products is "Standard" unless otherwise expressly specified in NEC
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(Note)
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defined above).
M8E 02. 11-1
User’s Manual U15331EJ4V1UD
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