Inc. Network Card User Manual

1-Gigabit Ethernet MAC v8.5 User Guide www.xilinx.com 87

UG144 April 24, 2009

Using the Optional Management Interface

-- DISCONTINUED PRODUCT --

There are two different transaction types of MDIO for write and read. They are described

in this section.

Abbreviations Used

The following abbreviations apply for the remainder of this chapter.

• PRE Preamble

• ST Start of frame

• OP Operation code

• PHYAD PHY address

• REGAD Register address

• TA Turnaround

Write Transaction

Figure 8-6 shows a write transaction across the MDIO, as defined by OP=’01.’ The

addressed MMD (PHYAD) device takes the 16-bit word in the data field and writes it to the

Figure 8-5: Typical MDIO-managed System

MAC 1 MAC 2

STA

mdc

mdio

MMD

Figure 8-6: MDIO Write Transaction

Z1 1 1 0 0 1 P4 P3 P2 P1 P0 R4 R3 R2 R1 R0 1 0 D15

D14

D13

D12

D11

D10

1 ZZZ

mdc

mdio

IDLE IDLE32 bits

PRE

ST OP PHYAD REGAD TA 16-bit WRITE DATA

STA drives MDIO