1Introduction
1.1PurposeofthePeripheral
1.2Features
User'sGuide
SPRUEQ6–December2007
EthernetMediaAccessController(EMAC)/Management
DataInput/Output(MDIO)
ThisdocumentprovidesafunctionaldescriptionoftheEthernetMediaAccessController(EMAC)and
physicallayer(PHY)deviceManagementDataInput/Output(MDIO)moduleintegratedin
theTMS320DM646xDigitalMediaSystem-on-Chip.IncludedarethefeaturesoftheEMACandMDIO
modules,adiscussionoftheirarchitectureandoperation,howthesemodulesconnecttotheoutside
world,andadescriptionoftheregistersforeachmodule.
TheEMACcontrolstheflowofpacketdatafromthesystemtothePHY.TheMDIOmodulecontrolsPHY
configurationandstatusmonitoring.
BoththeEMACandtheMDIOmodulesinterfacetothesystemcorethroughacustominterfacethat
allowsefficientdatatransmissionandreception.ThiscustominterfaceisreferredtoastheEMACcontrol
moduleandisconsideredintegraltotheEMAC/MDIOperipheral.
TheEMACmoduleisusedtomovedatabetweentheDM646xDMSoCandanotherhostconnectedtothe
samenetwork,incompliancewiththeEthernetprotocol.TheEMACiscontrolledbytheARMCPUofthe
device;controlbytheDSPCPUisnotsupported.
TheEMAC/MDIOhasthefollowingfeatures:
•Synchronous10/100/1000Mbpsoperation.
•G/MIIinterfacetothephysicallayerdevice(PHY).
•Full-duplexgigabitoperation(half-duplexnotsupported).
•EMACactsasDMAmastertoeitherinternalorexternaldevicememoryspace.
•HardwareerrorhandlingincludingCRC.
•EightreceivechannelswithVLANtagdiscriminationforreceivequality-of-service(QOS)support.
•Eighttransmitchannelswithround-robinorfixedpriorityfortransmitquality-of-service(QOS)support.
•Ether-Statsand802.3-StatsRMONstatisticsgathering.
•TransmitCRCgenerationselectableonaperchannelbasis.
•Broadcastframesselectionforreceptiononasinglechannel.
•Multicastframesselectionforreceptiononasinglechannel.
•Promiscuousreceivemodeframesselectionforreceptiononasinglechannel(allframes,allgood
frames,shortframes,errorframes).
•Hardwareflowcontrol.
•8K-bytelocalEMACdescriptormemorythatallowstheperipheraltooperateondescriptorswithout
affectingtheCPU.Thedescriptormemoryholdsenoughinformationtotransferupto512Ethernet
packetswithoutCPUintervention.
•Programmableinterruptlogicpermitsthesoftwaredrivertorestrictthegenerationofback-to-back
interrupts,whichallowsmoreworktobeperformedinasinglecalltotheinterruptserviceroutine.
•TIAdaptivePerformanceOptimizationforimprovedhalfduplexperformance.
•Configurablereceiveaddressmatching/filtering,receiveFIFOdepth,andtransmitFIFOdepth.
12EthernetMediaAccessController(EMAC)/ManagementDataInput/Output(MDIO)SPRUEQ6–December2007
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