PIC18F2455/2550/4455/4550 Data Sheet 28/40/44-Pin, High-Performance, Enhanced Flash, USB Microcontrollers with nanoWatt Technology 2006 Microchip Technology Inc. Preliminary DS39632CNote the following details of the code protection feature on Microchip devices: Microchip products meet the specification contained in their particular Microchip Data Sheet. Microchip believes that its family of products is one of the most secure families of its kind on the market today, when used in the intended manner and under normal conditions. There are dishonest and possibly illegal methods used to breach the code protection feature. All of these methods, to our knowledge, require using the Microchip products in a manner outside the operating specifications contained in Microchips Data Sheets. Most likely, the person doing so is engaged in theft of intellectual property. Microchip is willing to work with the customer who is concerned about the integrity of their code. Neither Microchip nor any other semiconductor manufacturer can guarantee the security of their code. Code protection does not mean that we are guaranteeing the product as unbreakable. Code protection is constantly evolving. We at Microchip are committed to continuously improving the code protection features of our products. Attempts to break Microchips code protection feature may be a violation of the Digital Millennium Copyright Act. If such acts allow unauthorized access to your software or other copyrighted work, you may have a right to sue for relief under that Act. Information contained in this publication regarding device Trademarks applications and the like is provided only for your convenience The Microchip name and logo, the Microchip logo, Accuron, and may be superseded by updates. It is your responsibility to dsPIC, KEELOQ, microID, MPLAB, PIC, PICmicro, PICSTART, ensure that your application meets with your specifications. PRO MATE, PowerSmart, rfPIC and SmartShunt are MICROCHIP MAKES NO REPRESENTATIONS OR WAR- registered trademarks of Microchip Technology Incorporated RANTIES OF ANY KIND WHETHER EXPRESS OR IMPLIED, in the U.S.A. and other countries. WRITTEN OR ORAL, STATUTORY OR OTHERWISE, AmpLab, FilterLab, Migratable Memory, MXDEV, MXLAB, RELATED TO THE INFORMATION, INCLUDING BUT NOT PICMASTER, SEEVAL, SmartSensor and The Embedded LIMITED TO ITS CONDITION, QUALITY, PERFORMANCE, Control Solutions Company are registered trademarks of MERCHANTABILITY OR FITNESS FOR PURPOSE. Microchip Technology Incorporated in the U.S.A. Microchip disclaims all liability arising from this information and its use. Use of Microchip devices in life support and/or safety Analog-for-the-Digital Age, Application Maestro, dsPICDEM, applications is entirely at the buyers risk, and the buyer agrees dsPICDEM.net, dsPICworks, ECAN, ECONOMONITOR, to defend, indemnify and hold harmless Microchip from any and FanSense, FlexROM, fuzzyLAB, In-Circuit Serial all damages, claims, suits, or expenses resulting from such Programming, ICSP, ICEPIC, Linear Active Thermistor, use. No licenses are conveyed, implicitly or otherwise, under MPASM, MPLIB, MPLINK, MPSIM, PICkit, PICDEM, any Microchip intellectual property rights. PICDEM.net, PICLAB, PICtail, PowerCal, PowerInfo, PowerMate, PowerTool, Real ICE, rfLAB, rfPICDEM, Select Mode, Smart Serial, SmartTel, Total Endurance, UNI/O, WiperLock and Zena are trademarks of Microchip Technology Incorporated in the U.S.A. and other countries. SQTP is a service mark of Microchip Technology Incorporated in the U.S.A. All other trademarks mentioned herein are property of their respective companies. 2006, Microchip Technology Incorporated, Printed in the U.S.A., All Rights Reserved. Printed on recycled paper. Microchip received ISO/TS-16949:2002 quality system certification for its worldwide headquarters, design and wafer fabrication facilities in Chandler and Tempe, Arizona and Mountain View, California in October 2003. The Companys quality system processes and procedures are for its PICmicro 8-bit MCUs, KEELOQ code hopping devices, Serial EEPROMs, microperipherals, nonvolatile memory and analog products. In addition, Microchips quality system for the design and manufacture of development systems is ISO 9001:2000 certified. DS39632C-page ii Preliminary 2006 Microchip Technology Inc.