Register Address (REGAD) - 3.5 English

Quad Serial Gigabit Media Independent LogiCORE Product Guide (PG029)

Document ID
PG029
Release Date
2023-11-02
Version
3.5 English

Having targeted a particular PHY using PHYAD, the individual configuration or status register within that particular PHY must now be addressed. This is achieved by placing the individual register address into the REGAD field of the MDIO frame (see MDIO Transactions ).

The REGAD field for an MDIO frame is a 5-bit binary value capable of addressing 32 unique addresses. The first 16 of these (registers 0 to 15) are defined by the IEEE 802.3-2008 Specification [Ref 2] . The remaining 16 (registers 16 to 31) are reserved for PHY vendors own register definitions.

For details of the register map of PHY layer devices and a more extensive description of the operation of the MDIO Interface, see IEEE 802.3-2008 Specification [Ref 2] .