PIC18F2420/2520/4420/4520 Data Sheet 28/40/44-Pin Enhanced Flash Microcontrollers with 10-Bit A/D and nanoWatt Technology 2008 Microchip Technology Inc. DS39631ENote 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and the like is provided only for your convenience The Microchip name and logo, the Microchip logo, Accuron, and may be superseded by updates.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, KEELOQ logo, MPLAB, PIC, PICmicro, ensure that your application meets with your specifications. PICSTART, rfPIC, SmartShunt and UNI/O are registered MICROCHIP MAKES NO REPRESENTATIONS OR trademarks of Microchip Technology Incorporated in the WARRANTIES OF ANY KIND WHETHER EXPRESS OR U.S.A. and other countries. IMPLIED, WRITTEN OR ORAL, STATUTORY OR FilterLab, Linear Active Thermistor, MXDEV, MXLAB, OTHERWISE, RELATED TO THE INFORMATION, SEEVAL, SmartSensor and The Embedded Control Solutions INCLUDING BUT NOT LIMITED TO ITS CONDITION, Company are registered trademarks of Microchip Technology QUALITY, PERFORMANCE, MERCHANTABILITY OR Incorporated in the U.S.A. FITNESS FOR PURPOSE. Microchip disclaims all liability arising from this information and its use. Use of Microchip Analog-for-the-Digital Age, Application Maestro, CodeGuard, devices in life support and/or safety applications is entirely at dsPICDEM, dsPICDEM.net, dsPICworks, dsSPEAK, ECAN, the buyers risk, and the buyer agrees to defend, indemnify and ECONOMONITOR, FanSense, In-Circuit Serial hold harmless Microchip from any and all damages, claims, Programming, ICSP, ICEPIC, Mindi, MiWi, MPASM, MPLAB suits, or expenses resulting from such use. No licenses are Certified logo, MPLIB, MPLINK, mTouch, PICkit, PICDEM, 32 conveyed, implicitly or otherwise, under any Microchip PICDEM.net, PICtail, PIC logo, PowerCal, PowerInfo, intellectual property rights. PowerMate, PowerTool, REAL ICE, rfLAB, Select Mode, Total Endurance, 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. 2008, Microchip Technology Incorporated, Printed in the U.S.A., All Rights Reserved. Printed on recycled paper. Microchip received ISO/TS-16949:2002 certification for its worldwide headquarters, design and wafer fabrication facilities in Chandler and Tempe, Arizona Gresham, Oregon and design centers in California and India. The Companys quality system processes and procedures are for its PIC MCUs and dsPIC DSCs, 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. DS39631E-page ii 2008 Microchip Technology Inc.