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pic24fj128ga010 family - Microchip

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PIC24FJ128GA010 FAMILY23.0 SPECIAL FEATURESNote:This data sheet summarizes the featuresof this group of PIC24F devices. It is notintended to be a comprehensive referencesource. Refer to Section 32. “High-LevelDevice Integration” (DS39719) in the“PIC24F Family Reference Manual” formore information.PIC24FJ128GA010 devices include several featuresintended to maximize application flexibility and reliability,and minimize cost through elimination of externalcomponents. These are:• Flexible Configuration• Watchdog Timer (WDT)• Code Protection• JTAG Boundary Scan Interface• In-Circuit Serial Programming• In-Circuit Emulation23.1 Configuration BitsThe Configuration bits can be programmed (read as‘0’), or left unprogrammed (read as ‘1’), to select variousdevice configurations. These bits are mappedstarting at program memory location F80000h. A completelist is shown in Table 23-1. A detailed explanationof the various bit functions is provided in Register 23-1through Register 23-4.Note that address F80000h is beyond the user programmemory space. In fact, it belongs to the configurationmemory space (800000h-FFFFFFh) which can only beaccessed using table reads and table writes.TABLE 23-1:DeviceFLASH CONFIGURATIONWORDS LOCATIONSConfiguration WordAddresses1 2PIC24FJ64GA 00ABFEh 00ABFChPIC24FJ96GA 00FFFEh 00FFFChPIC24FJ128GA 0157FEh 0157FChWhen creating applications for these devices, usersshould always specifically allocate the location of theFlash Configuration Word for configuration data. This isto make certain that program code is not stored in thisaddress when the code is compiled.The Configuration bits are reloaded from the FlashConfiguration Word on any device Reset.The upper byte of both Flash Configuration Words inprogram memory should always be ‘1111 1111’. Thismakes them appear to be NOP instructions in theremote event that their locations are ever executed byaccident. Since Configuration bits are not implementedin the corresponding locations, writing ‘1’s to theselocations has no effect on device operation.23.1.1 CONSIDERATIONS FORCONFIGURING PIC24FJ128GA010FAMILY DEVICESIn PIC24FJ128GA010 <strong>family</strong> devices, the configurationbytes are implemented as volatile memory. This meansthat configuration data must be programmed each timethe device is powered up. Configuration data is storedin the two words at the top of the on-chip programmemory space, known as the Flash ConfigurationWords. Their specific locations are shown inTable 23-1. These are packed representations of theactual device Configuration bits, whose actuallocations are distributed among five locations in configurationspace. The configuration data is automaticallyloaded from the Flash Configuration Words to theproper Configuration registers during device Resets.Note: Configuration data is reloaded on all typesof device resets.© 2009 <strong>Microchip</strong> Technology Inc. DS39747E-page 189

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