MDIO Transactions - 16.2 English

1G/2.5G Ethernet PCS/PMA or SGMII LogiCORE IP Product Guide (PG047)

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16.2 English

All transactions, read or write, are initiated by the MDIO master. All MDIO slave devices, when addressed, must respond. MDIO transactions take the form of an MDIO frame, containing fields for transaction type, address and data. This MDIO frame is transferred across the MDIO wire synchronously to MDC. The abbreviations used in this section are explained in the following table.

Table 1. Abbreviations and Terms
Abbreviation Term
PRE Preamble
ST Start of frame
OP Operation code
PHYAD Physical address
REGAD Register address
TA Turnaround