Computer Hardware User Manual

E‐14HardwareReferenceManual www.picocomputing.com PicoComputing,Inc.
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7
FieldProgrammableGateArray
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ThecoreofthePicoE‐14isahighperformanceVirtex‐4FPGA.IncludedintheFPGAaretheFPGA
Fabric,aPower‐PC™processor,ultrahigh‐speedDSPslicesandDDR2RAM.
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FPGAFabric:
The“Fabric”ofanFPGAcomprisesanarrayoflogicelementsthatcan
beconnectedinvirtually
unlimitedpatterns.Thesepatternsoflogicelementscanbeusedtoperformbasicmathematical
functionssuchasadditionandsubtraction,orcanbegroupedtogethertoperformcomplexfunctions
likeFastFourierTransforms.Logicelementscanevenbeconnectedtocreateacustomsoftprocessor.
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TheadvantageoftheFPGAisthattheinternallogiccanbeoptimizedforaspecificapplication.FPGAs
arealsoabletoexecuteoperationsinparallel,notbeinglimitedbysequentialexecutionlikea
traditionalprocessor.FPGAoperationscanbeexecutedinaparallel,pipelinedorevenan
asynchronousmanner.TheFPGAallowsincredibleapplicationspeedwithverylowpower
consumption.Yourimaginationisreallythelimit.
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DSPSlice:
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EmbeddedwithintheFPGAarespecialareasthataredesignedtofacilitatehighspeed“digitalsignal
processing.”TheseareasarecalledDSPslices.TheDSPslicecanbeconfiguredinavarietyofdifferent
ways.ForexampleoneDSPslicecanbeconfiguredtobeonetapofanFIRfilter.DSPslicesarefully
pipelinedandfeatureincrediblespeed.WhenconfiguredforFIRfilteringtheDSPslicehasa
guaranteedperformanceof500MHzwithalatencyofonecycle.An18x18multiplyandaccumulate
alsorunsat250MHzwithalatencyoftwocycles.Smallerdatawidthsallowhigherclockspeeds.
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FPGAResources:
FreeFPGACores www.opencores.org
Virtex‐4Website www.xilinx.com/virtex4
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