PIC18F2420/2520/4420/4520 Data Sheet 28/40/44-Pin Enhanced Flash Microcontrollers with 10-Bit A/D and nanoWatt Technology 2004 Microchip Technology Inc. Preliminary DS39631ANote 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and the like is intended through suggestion only The Microchip name and logo, the Microchip logo, Accuron, and may be superseded by updates.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 No representation or warranty is given and no liability is registered trademarks of Microchip Technology Incorporated assumed by Microchip Technology Incorporated with respect in the U.S.A. and other countries. to the accuracy or use of such information, or infringement of AmpLab, FilterLab, MXDEV, MXLAB, PICMASTER, SEEVAL, patents or other intellectual property rights arising from such SmartSensor and The Embedded Control Solutions Company use or otherwise. Use of Microchips products as critical are registered trademarks of Microchip Technology components in life support systems is not authorized except Incorporated in the U.S.A. with express written approval by Microchip. No licenses are conveyed, implicitly or otherwise, under any intellectual Analog-for-the-Digital Age, Application Maestro, dsPICDEM, property rights. dsPICDEM.net, dsPICworks, ECAN, ECONOMONITOR, FanSense, FlexROM, fuzzyLAB, In-Circuit Serial Programming, ICSP, ICEPIC, Migratable Memory, MPASM, MPLIB, MPLINK, MPSIM, PICkit, PICDEM, PICDEM.net, PICLAB, PICtail, PowerCal, PowerInfo, PowerMate, PowerTool, rfLAB, rfPICDEM, Select Mode, Smart Serial, SmartTel and Total Endurance 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. 2004, 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. DS39631A-page ii Preliminary 2004 Microchip Technology Inc.