<strong>PIC16F84A</strong>PPackaging .......................................................................... 55PICDEM-1 Low-Cost PICmicro Demo Board ..................... 36PICDEM-2 Low-Cost PIC16CXX Demo Board .................. 36PICDEM-3 Low-Cost PIC16CXXX Demo Board ................ 36PICSTART® Plus Entry Level Development System ........ 35Pinout Descriptions .............................................................. 4Pointer, FSR ....................................................................... 11PORTA ........................................................................... 4, 13Initializing ................................................................... 13PORTA Register ........................................ 7, 13, 14, 24RA3:RA0 Block Diagram ............................................ 13RA4 Block Diagram .................................................... 14RA4/T0CKI Pin ................................................. 4, 13, 17TRISA Register .................................... 7, 13, 14, <strong>18</strong>, 24PORTB ........................................................................... 4, 15Initializing ................................................................... 15PORTB Register ........................................ 7, 15, 16, 24Pull-up Enable (RBPU <strong>Bit</strong>) ........................................... 9RB0/INT Edge Select (INTEDG <strong>Bit</strong>) ............................. 9RB0/INT Pin, External ...................................... 4, 16, 29RB3:RB0 Block Diagram ............................................ 15RB7:RB4 Block Diagram ............................................ 15RB7:RB4 Interrupt on Change ......................... 4, 15, 29RB7:RB4 Interrupt on Change Enable (RBIE <strong>Bit</strong>) ...... 10RB7:RB4 Interrupt on Change Flag (RBIF <strong>Bit</strong>) .... 10, 15TRISB Register .......................................... 7, 15, 16, 24Power-on Reset (POR) .......................................... 21, 23, 25Oscillator Start-up Timer (OST) ........................... 21, 25PD <strong>Bit</strong> ............................................. 8, 23, 28, 31, 32, 34Power-up Timer (PWRT) ..................................... 21, 25PWRT Enable (PWRTE <strong>Bit</strong>) ....................................... 21Time-out Sequence .................................................... 28Time-out Sequence on Power-up ........................ 26, 27TO <strong>Bit</strong> ....................................... 8, 23, 28, 30, 31, 32, 34Prescaler ............................................................................ 17Assignment (PSA <strong>Bit</strong>) ............................................ 9, 17Block Diagram ............................................................ <strong>18</strong>Rate Select (PS2:PS0 <strong>Bit</strong>s) ................................... 9, 17Switching Prescaler Assignment ................................ <strong>18</strong>PRO MATE® II Universal Programmer .............................. 35Product Identification System ............................................. 67Program Counter ................................................................ 11PCL Register .................................................... 7, 11, 24PCLATH Register ............................................ 7, 11, 24Reset Conditions ........................................................ 24Program Memory ................................................................. 5General Purpose Registers .......................................... 6Interrupt Vector ...................................................... 5, 29Reset Vector ................................................................ 5Special Function Registers ...................................... 6, 7Programming, Device Instructions ..................................... 33RRAM. See <strong>Data</strong> MemoryReader Response .............................................................. 66Register File ......................................................................... 6Reset ............................................................................ 21, 23Block Diagram ............................................................ 23Reset Conditions for All Registers ............................. 24Reset Conditions for Program Counter ...................... 24Reset Conditions for STATUS Register ..................... 24WDT Reset. See Watchdog Timer (WDT)Revision History ................................................................. 59SSaving W Register and STATUS in RAM .......................... 29SEEVAL® Evaluation and Programming System .............. 37SLEEP ............................................................. 21, 23, 29, 31Software Simulator (MPLAB-SIM) ..................................... 37Special Features of the CPU ............................................. 21Special Function Registers .............................................. 6, 7Speed, Operating ..................................................... 1, 22, 49Stack .................................................................................. 11STATUS Register ................................................ 7, 8, 24, 29C <strong>Bit</strong> ....................................................................... 8, 34DC <strong>Bit</strong> .................................................................... 8, 34PD <strong>Bit</strong> ............................................ 8, 23, 28, 31, 32, 34Reset Conditions ....................................................... 24RP0 <strong>Bit</strong> .................................................................... 6, 8TO <strong>Bit</strong> ...................................... 8, 23, 28, 30, 31, 32, 34Z <strong>Bit</strong> ....................................................................... 8, 34TTime-out (TO) <strong>Bit</strong>. See Power-on Reset (POR)Timer0 ................................................................................ 17Block Diagram ........................................................... 17Clock Source Edge Select (T0SE <strong>Bit</strong>) ......................... 9Clock Source Select (T0CS <strong>Bit</strong>) .................................. 9Overflow Enable (T0IE <strong>Bit</strong>) .................................. 10, 29Overflow Flag (T0IF <strong>Bit</strong>) ................................ 10, <strong>18</strong>, 29Overflow Interrupt ................................................ <strong>18</strong>, 29RA4/T0CKI Pin, External Clock ................................. 17TMR0 Register ................................................ 7, <strong>18</strong>, 24Timing DiagramsDiagrams and Specifications ..................................... 49Time-out Sequence on Power-up ........................ 26, 27WW Register ................................................................... 24, 29Wake-up from SLEEP ................................ 21, 25, 28, 29, 31Interrupts ............................................................. 31, 32MCLR Reset .............................................................. 31WDT Reset ................................................................ 31Watchdog Timer (WDT) ............................................... 21, 30Block Diagram ........................................................... 30Enable (WDTE <strong>Bit</strong>) .................................................... 21Programming Considerations .................................... 30RC Oscillator ............................................................. 30Time-out Period ......................................................... 30WDT Reset, Normal Operation .................................. 23WDT Reset, SLEEP ............................................ 23, 31WWW, On-Line Support ................................................ 2, 65DS35007A-page 64 Preliminary © 1998 Microchip Technology Inc.
<strong>PIC16F84A</strong>ON-LINE SUPPORTMicrochip provides on-line support on the MicrochipWorld Wide Web (WWW) site.The web site is used by Microchip as a means to makefiles and information easily available to customers. Toview the site, the user must have access to the Internetand a web browser, such as Netscape or MicrosoftExplorer. Files are also available for FTP downloadfrom our FTP site.Connecting to the Microchip Internet Web SiteThe Microchip web site is available by using yourfavorite Internet browser to attach to:www.microchip.comThe file transfer site is available by using an FTP serviceto connect to:ftp://ftp.futureone.com/pub/microchipThe web site and file transfer site provide a variety ofservices. Users may download files for the latestDevelopment Tools, <strong>Data</strong> <strong>Sheet</strong>s, Application Notes,User's Guides, Articles and Sample Programs. A varietyof Microchip specific business information is alsoavailable, including listings of Microchip sales offices,distributors and factory representatives. Other dataavailable for consideration is:• Latest Microchip Press Releases• Technical Support Section with Frequently AskedQuestions• Design Tips• Device Errata• Job Postings• Microchip Consultant Program Member Listing• Links to other useful web sites related toMicrochip Products• Conferences for products, Development Systems,technical information and more• Listing of seminars and eventsSystems Information and Upgrade Hot LineThe Systems Information and Upgrade Line providessystem users a listing of the latest versions of all ofMicrochip's development systems software products.Plus, this line provides information on how customerscan receive any currently available upgrade kits.TheHot Line Numbers are:1-800-755-2345 for U.S. and most of Canada, and1-602-786-7302 for the rest of the world.980106Trademarks: The Microchip name, logo, PIC, PICSTART,PICMASTER and PRO MATE are registered trademarks ofMicrochip Technology Incorporated in the U.S.A. and othercountries. PICmicro, FlexROM, MPLAB and fuzzyLAB aretrademarks and SQTP is a service mark of Microchip inthe U.S.A.All other trademarks mentioned herein are the property oftheir respective companies.© 1998 Microchip Technology Inc. Preliminary DS35007A-page 65
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