4.3PHYAcknowledgeStatusRegister(ALIVE)
4.4PHYLinkStatusRegister(LINK)
MDIORegisters
ThePHYacknowledgestatusregister(ALIVE)isshowninFigure29anddescribedinTable27.
Figure29.PHYAcknowledgeStatusRegister(ALIVE)
3116
ALIVE
R/W1C-0
150
ALIVE
R/W1C-0
LEGEND:R/W=Read/Write;W1C=Write1toclear,writeof0hasnoeffect;-n=valueafterreset
Table27.PHYAcknowledgeStatusRegister(ALIVE)FieldDescriptions
BitFieldValueDescription
31-0ALIVE0-FFFFFFFFhMDIOAlivebits.Eachofthe32bitsofthisregisterissetifthemostrecentaccesstothePHYwith
addresscorrespondingtotheregisterbitnumberwasacknowledgedbythePHY;thebitisresetif
thePHYfailstoacknowledgetheaccess.BoththeuserandpollingaccessestoaPHYwillcause
thecorrespondingalivebittobeupdated.Thealivebitsareonlymeanttobeusedtogivean
indicationofthepresenceornotofaPHYwiththecorrespondingaddress.Writinga1toanybit
willclearit,writinga0hasnoeffect.
0ThePHYfailstoacknowledgetheaccess.
1ThemostrecentaccesstothePHYwithanaddresscorrespondingtotheregisterbitnumberwas
acknowledgedbythePHY.
ThePHYlinkstatusregister(LINK)isshowninFigure30anddescribedinTable28.
Figure30.PHYLinkStatusRegister(LINK)
3116
LINK
R-0
150
LINK
R-0
LEGEND:R=Readonly;-n=valueafterreset
Table28.PHYLinkStatusRegister(LINK)FieldDescriptions
BitFieldValueDescription
31-0LINK0-FFFFFFFFhMDIOLinkstatebits.ThisregisterisupdatedafterareadofthegenericstatusregisterofaPHY.
ThebitissetifthePHYwiththecorrespondingaddresshaslinkandthePHYacknowledgesthe
readtransaction.ThebitisresetifthePHYindicatesitdoesnothavelinkorfailstoacknowledge
thereadtransaction.Writestotheregisterhavenoeffect.
0ThePHYindicatesitdoesnothavealinkorfailstoacknowledgethereadtransaction
1ThePHYwiththecorrespondingaddresshasalinkandthePHYacknowledgestheread
transaction.
SPRUEQ6–December2007EthernetMediaAccessController(EMAC)/ManagementDataInput/Output(MDIO)73
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