NOTES FOR CMOS DEVICES
1
PRECAUTION AGAINST ESD FOR SEMICONDUCTORS
Note:
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 once, when it has occurred. Environmental control
must be adequate. When it is dry, humidifier should be used. It is recommended to avoid using
insulators that easily build 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 bench and floor should be grounded. The operator should be grounded using
wrist strap. Semiconductor devices must not be touched with bare hands. Similar precautions need
to be taken for PW boards with semiconductor devices on it.
2
HANDLING OF UNUSED INPUT PINS FOR CMOS
Note:
No connection for CMOS device inputs can be cause of malfunction. If no connection is provided
to the input pins, it is possible that an internal input level may be generated due to noise, etc., hence
causing malfunction. CMOS devices behave differently than Bipolar or NMOS devices. Input levels
of CMOS devices must be fixed high or low by using a pull-up or pull-down circuitry. Each unused
pin should be connected to V
DD
or GND with a resistor, if it is considered to have a possibility of
being an output pin. All handling related to the unused pins must be judged device by device and
related specifications governing the devices.
3
STATUS BEFORE INITIALIZATION OF MOS DEVICES
Note:
Power-on does not necessarily define initial status of MOS device. Production process of MOS
does not define the initial operation status of the device. Immediately after the power source is
turned ON, the devices with reset function have not yet been initialized. Hence, power-on does
not guarantee out-pin levels, I/O settings or contents of registers. Device is not initialized until the
reset signal is received. Reset operation must be executed immediately after power-on for devices
having reset function.
User’s Manual S16617EJ1V0UM
3
USB logo is a trademark of USB Implementers Forum, Inc.
•
The information in this document is current as of May, 2003. 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
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appear in this document.
•
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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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redundancy, fire-containment and anti-failure features.
•
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The "Specific" quality grade applies only to NEC Electronics products developed based on a customer-
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The quality grade of NEC Electronics products is "Standard" unless otherwise expressly specified in NEC
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(Note)
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M8E 02. 11-1
4
User’s Manual S16617EJ1V0UM
PREFACE
Readers
This manual is intended for engineers who need to be familiar with the capability of
the
µ
PD720112 in order to develop application systems based on it.
The purpose of this manual is to help users understand the hardware capabilities
(listed below) of the
µ
PD720112.
This manual consists of the following chapters:
•
Introduction
•
Pin functions
•
Descriptors Information
•
USB requests information
•
External serial ROM interface
•
How to connect to external discrete components
•
Product specifications
Purpose
Configuration
Guidance
Readers of this manual should already have a general knowledge of electronics, logic
circuits, and microcomputers.
Notation
This manual uses the following conventions:
Data bit significance:
Active low:
Note:
Caution:
Remark:
Numerical value:
High-order bits on the left side;
low-order bits on the right side
XXXXB (Pin and signal names are suffixed with B.)
Explanation of an indicated part of text
Information requiring the user’s special attention
Supplementary information
Binary ... xxxx or xxxxb
Decimal ... xxxx
Hexadecimal ... xxxxh
Related Document
Use this manual in combination with the following document.
The related documents indicated in this publication may include preliminary versions.
However, preliminary versions are not marked as such.
•
µ
PD720112 Data Sheet: S16616E
User’s Manual S16617EJ1V0UM
5
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