User’s Manual
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PD789426, 789436, 789446,
789456 Subseries
8-Bit Single-Chip Microcontrollers
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PD789425
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PD789426
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PD789435
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PD789436
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PD78F9436
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PD789445
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PD789446
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PD789455
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PD789456
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PD78F9456
Document No. U15075EJ2V1UD00 (2nd edition)
Date Published August 2005 N CP(K)
©
Printed in Japan
[MEMO]
2
User’s Manual U15075EJ2V1UD
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 U15075EJ2V1UD
3
FIP and EEPROM 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.
4
User’s Manual U15075EJ2V1UD
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.
•
The information in this document is current as of August, 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
property rights of third parties by or arising from the use of NEC Electronics products listed in this document
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.
•
While NEC Electronics endeavors to enhance the quality, reliability and safety of NEC Electronics products,
customers agree and acknowledge that the possibility of defects thereof cannot be eliminated entirely. To
minimize risks of damage to property or injury (including death) to persons arising from defects in NEC
Electronics products, customers must incorporate sufficient safety measures in their design, such as
redundancy, fire-containment and anti-failure features.
•
NEC Electronics products are classified into the following three quality grades: "Standard", "Special" and
"Specific".
The "Specific" quality grade applies only to NEC Electronics products developed based on a customer-
designated "quality assurance program" for a specific application. The recommended applications of an NEC
Electronics product depend on its quality grade, as indicated below. Customers must check the quality grade of
each NEC Electronics product before using it in a particular application.
"Standard": Computers, office equipment, communications equipment, test and measurement equipment, audio
and visual equipment, home electronic appliances, machine tools, personal electronic equipment
and industrial robots.
"Special": Transportation equipment (automobiles, trains, ships, etc.), traffic control systems, anti-disaster
systems, anti-crime systems, safety equipment and medical equipment (not specifically designed
for life support).
"Specific": Aircraft, aerospace equipment, submersible repeaters, nuclear reactor control systems, life
support systems and medical equipment for life support, etc.
The quality grade of NEC Electronics products is "Standard" unless otherwise expressly specified in NEC
Electronics data sheets or data books, etc. If customers wish to use NEC Electronics products in applications
not intended by NEC Electronics, they must contact an NEC Electronics sales representative in advance to
determine NEC Electronics' willingness to support a given application.
(Note)
(1) "NEC Electronics" as used in this statement means NEC Electronics Corporation and also includes its
majority-owned subsidiaries.
(2) "NEC Electronics products" means any product developed or manufactured by or for NEC Electronics (as
defined above).
M8E 02. 11-1
User’s Manual U15075EJ2V1UD
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