Atmel ATmega128RFA1單片IEEE 802.15.4解決方案

AtmelATmega128RFA1單片IEEE802.15.4解決方案Atmel公司的ATmega128RFA1是低功耗單片IEEE802.15.4解決方案,集成了基于AVR增強(qiáng)特性RISC架構(gòu)的CMOS8位MCU以及2.4GHzISM頻段的高數(shù)據(jù)速率收發(fā)器.器件的吞吐量達(dá)到1MIPS/MHz,無線電收發(fā)器的數(shù)據(jù)數(shù)據(jù)速率從250kbps到高達(dá)2Mbps.ATmega128RFA1廣泛應(yīng)用在ZigBee?/IEEE802.15.4-2006/2003?,RF4CE,SP100,WirelessHART?,ISM應(yīng)用以及IPv6/6LoWPAN.本文介紹了ATmega128RFA1主要特性,方框圖,AVR架構(gòu)方框圖,收發(fā)器方框圖以及基本應(yīng)用電路圖和材料清單(BOM)與擴(kuò)展特性的應(yīng)用電路圖.

TheATmega128RFA1isalow-powerCMOS8bitmicrocontrollerbasedontheAVR

enhancedRISCarchitecturecombinedwithahighdataratetransceiverforthe2.4GHz

ISMband.ItisderivedfromtheATmega1281microcontrollerandtheAT86RF231radio

transceiver.

Byexecutingpowerfulinstructionsinasingleclockcycle,thedeviceachievesthroughputsapproaching1MIPSperMHzallowingthesystemdesignertooptimizepowerconsumptionversusprocessingspeed.

Theradiotransceiverprovideshighdataratesfrom250kb/supto2Mb/s,framehandling,outstandingreceiversensitivityandhightransmitoutputpowerenablingaveryrobustwirelesscommunication.

TheAVRcorecombinesarichinstructionsetwith32generalpurposeworkingregisters.All32registersaredirectlyconnectedtotheArithmeticLogicUnit(ALU).Twoindependentregisterscanbeaccessedwithonesingleinstructionexecutedinoneclockcycle.TheresultingarchitectureisverycodeefficientwhileachievingthroughputsuptotentimesfasterthanconventionalCISCmicrocontrollers.Thesystemincludesinternalvoltageregulationandanadvancedpowermanagement.Distinguishedbythesmallleakagecurrentitallowsanextendedoperationtimefrombattery.

TheradiotransceiverisafullyintegratedZigBeesolutionusingaminimumnumberofexternalcomponents.ItcombinesexcellentRFperformancewithlowcost,smallsizeandlowcurrentconsumption.Theradiotransceiverincludesacrystalstabilizedfractional-Nsynthesizer,transmitterandreceiver,andfullDirectSequenceSpreadSpectrumSignal(DSSS)processingwithspreadinganddespreading.ThedeviceisfullycompatiblewithIEEE802.15.4-2006/2003andZigBeestandards.

ATmega128RFA1主要特性:

?HighPerformance,LowPowerAVR?8-BitMicrocontroller

?AdvancedRISCArchitecture

-135PowerfulInstructions–MostSingleClockCycleExecution

-32x8GeneralPurposeWorkingRegisters

-FullyStaticOperation

-Upto16MIPSThroughputat16MHzand1.8V

-On-Chip2-cycleMultiplier

?Non-volatileProgramandDataMemories

-128KBytesofIn-SystemSelf-ProgrammableFlash

?Endurance:2000Write/EraseCycles@85℃

-4KBytesEEPROM

?Endurance:2000Write/EraseCycles@85℃

-16KBytesInternalSRAM

?JTAG(IEEEstd.1149.1compliant)Interface

-Boundary-scanCapabilitiesAccordingtotheJTAGStandard

-ExtensiveOn-chipDebugSupport

-ProgrammingofFlashEEPROM,FusesandLockBitsthroughtheJTAGinterface

?PeripheralFeatures

-MultipleTimer/Counter&PWMchannels

-RealTimeCounterwithSeparateOscillator

-10-bit,330ks/sA/DConverter;AnalogComparator;On-chipTemperatureSensor

-Master/SlaveSPISerialInterface

-TwoProgrammableSerialUSART

-ByteOriented2-wireSerialInterface

?AdvancedInterruptHandler

?WatchdogTimerwithSeparateOn-ChipOscillator

?Power-onResetandLowCurrentBrown-OutDetector

?AdvancedPowerSaveModes

?FullyintegratedLowPowerTransceiverfor2.4GHzISMBand

-SupportedDataRates:250kb/sand500kb/s,1Mb/s,2Mb/s

--100dBmRXSensitivity;TXOutputPowerupto3.5dBm

-HardwareAssistedMAC(Auto-Acknowledge,Auto-Retry)

-32BitIEEE802.15.4SymbolCounter

-BasebandSignalProcessing

-SFR-Detection,Spreading;De-Spreading;Framing;CRC-16Computation

-AntennaDiversityandTX/RXcontrol

-TX/RX128ByteFrameBuffer

?HardwareSecurity(AES,TrueRandomGenerator)

?IntegratedCrystalOscillators(32.768kHz&16MHz)

?I/OandPackage

-38ProgrammableI/OLines

-64-padQFN(RoHS/FullyGreen)

?TemperatureRange:-40℃to85℃Industrial

?Supplyvoltagerange1.8Vto3.6Vwithintegratedvoltageregulators

?UltraLowPowerconsumption(1.8to3.6V)forRx/Tx&AVR:<18.6mA

-CPUActiveMode(16MHz):4.1mA

-2.4GHzTransceiver:RX_ON12.5mA/TX14.5mA(maximumTXoutputpower)

-DeepSleepMode:<250nA@25℃

?SpeedGrade:0–16MHz@1.8–3.6V

ATmega128RFA1應(yīng)用:

?ZigBee?/IEEE802.15.4-2006/2003?–FullAndReducedFunctionDevice(FFD/RFD)

?GeneralPurpose2.4GHzISMBandTransceiverwithMicrocontroller

?RF4CE,SP100,WirelessHART?,ISMApplicationsandIPv6/6LoWPAN

圖1.ATmega128RFA1方框圖

ThemainfunctionoftheCPUcoreistoensurecorrectprogramexecution.TheCPUmustthereforebeabletoaccessmemories,performcalculation,controlperipherals,andhandleinterrupts.

Inordertomaximizeperformanceandparallelism,theAVRusesaHarvardarchitecture–withseparatememoriesandbusesforprogramanddata.Instructionsintheprogrammemoryareexecutedwithasinglelevelpipelining.Whileoneinstructionisbeingexecuted,thenextinstructionispre-fetchedfromtheprogrammemory.Thisconceptenablesinstructionstobeexecutedineveryclockcycle.TheprogrammemoryisIn-SystemReprogrammableFlashmemory.

圖2.ATmega128RFA1的AVR架構(gòu)方框圖

TheATmega128RFA1featuresalow-power2.4GHzradiotransceiverdesignedforindustrialandconsumerZigBee/IEEE802.15.4,6LoWPAN,RF4CEandhighdatarate2.4GHzISMbandapplications.TheradiotransceiverisatrueperipheralblockoftheAVRmicrocontroller.AllRF-criticalcomponentsexcepttheantenna,crystalanddecouplingcapacitorsareintegratedon-chip.Therefore,theATmega128RFA1isparticularlysuitableforapplicationslike:

2.4GHzIEEE802.15.4andZigBeesystems

6LoWPANandRF4CEsystems

Wirelesssensornetworks

Industrialcontrol,sensingandautomation(SP100,WirelessHART)

Residentialandcommercialautomation

Healthcare

Consumerelectronics

PCperipherals

Low-Power2.4GHzTransceiverFeatures

HighperformanceRF-CMOS2.4GHzradiotransceivertargetedforIEEE802.15.4?,ZigBee?,IPv6/6LoWPAN,RF4CE,SP100,WirelessHART?andISMapplications

Outstandinglinkbudget(103.5dB):

Receiversensitivity-100dBm

Programmableoutputpowerfrom-17dBmupto+3.5dBm

Ultra-lowcurrentconsumption:

TRX_OFF=0.4mA

RX_ON=12.5mA

BUSY_TX=14.5mA(atmax.transmitpowerof+3.5dBm)

OptimizedforlowBoMcostandeaseofproduction:

Fewexternalcomponentsnecessary(crystal,capacitorsandantenna)

ExcellentESDrobustness

Easytouseinterface:

Registersandframebufferaccessfromsoftware

Dedicatedradiotransceiverinterrupts

Radiotransceiverfeatures:

128byteFIFO(SRAM)fordatabuffering

IntegratedRX/TXswitch

Fullyintegrated,fastsettlingPLLtosupportfrequencyhopping

Batterymonitor

Fastwake-uptime<0.25ms

SpecialIEEE802.15.42006hardwaresupport:

FCScomputationandclearchannelassessment(CCA)

RSSImeasurement,energydetectionandlinkqualityindication

MAChardwareaccelerator:

Automatedacknowledgement,CSMA-CAandframeretransmission

Automaticaddressfiltering

AutomatedFCScheck

ExtendedFeatureSetHardwareSupport:

AES128bithardwareaccelerator

RX/TXindication(externalRFfront-endcontrol)

RXantennadiversity

SupportedPSDUdatarates:250kb/s,500kb/s,1Mb/sand2Mb/s

Truerandomnumbergenerationforsecurityapplications

ComplianttoIEEE802.15.4-2006,IEEE802.15.4-2003andRF4CE

ComplianttoEN300328/440,FCC-CFR-47Part15,ARIBSTD-66,RSS-210

圖3.ATmega128RFA1收發(fā)器方框圖

圖4.ATmega128RFA1基本應(yīng)用電路圖

The50ohmsingle-endedRFinputistransformedtothe100differentialRFportimpedanceusingBalunB1.ThecapacitorsC1andC2provideACcouplingoftheRFinputtotheRFport,capacitorC4improvesmatching.

Thepowersupplybypasscapacitors(CB2,CB4)areconnectedtotheexternalanalogsupplypin(EVDD,pin59)andexternaldigitalsupplypin(DEVDD,pin23).Pins34,44and54supplythedigitalportpins.

CapacitorsCB1andCB3arebypasscapacitorsfortheintegratedanaloganddigitalvoltageregulatorstoensurestableoperationandtoimprovenoiseimmunity.

Capacitorsshouldbeplacedascloseaspossibletothepinsandshouldhavealowresistanceandlow-inductanceconnectiontogroundtoachievethebestperformance.

Thecrystal(XTAL),thetwoloadcapacitors(CX1,CX2),andtheinternalcircuitryconnectedtopinsXTAL1andXTAL2formthe16MHzcrystaloscillatorforthe2.4GHztransceiver.Toachievethebest