PIC18F to PIC24F Migration: An Overview - Microchip

SUMMARYThe preceding represents the most important considerationsfor moving a legacy, 8-bit PIC18F application to aPIC24F platform. Since there are so many ways forimplementing a given solution, it is impractical in thisspace to list every possible code or algorithm translationinto its 16-bit equivalent. Instead, this document shouldbe thought of as a checklist of the most importantdifferences between those features shared by bothdevice families.Nor does this document consider all the possibilities ofthe PIC24F architecture and its expanded peripheral set.Features, such as the Programmable CRC Generator,hardware Real-Time Clock/Calendar and ParallelMaster Port, may offer the chance for making an existingapplication smaller and more efficient. Ultimately, theuser will need to review their application’s design andimplementation, and make the decisions as to how theircode and hardware design must be changed to work onthe new platform.REFERENCESFor more specific information on the device familiesused as the basis for this document, please refer to thefollowing data sheets:• “PIC18F8722 Family Data Sheet” (DS39646)• “PIC24FJ128GA Family Data Sheet” (DS39747)Detailed information on oscillator design and troubleshootingfor PICmicro microcontroller applications isprovided in these Microchip application notes:• AN826, “Crystal Oscillator Basics and CrystalSelection for rfPIC ® and PICmicro ® Devices”(DS00826)• AN849, “Basic PICmicro ® Oscillator Design”(DS00849)• AN943, “Practical PICmicro ® Oscillator Analysisand Design” (DS00943)• AN949, “Making Your Oscillator Work” (DS00949)Microchip also has additional data sheet and referencematerial available for PIC18F, PIC18FXXJ Flash andPIC24F devices that may be helpful in planning themigration of an application. For a complete listing ofavailable materials, users are encouraged to visit theMicrochip corporate web site at:www.microchip.com© 2006 Microchip Technology Inc. DS39764A-page 45