Figure 8-5: Typical Mdio-Managed System; Figure 8-6: Mdio Write Transaction - Xilinx LogiCORE IP MAC v8.5 User Manual

Using the Optional Management Interface
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.
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Write Transaction
Figure 8-6
addressed MMD (PHYAD) device takes the 16-bit word in the data field and writes it to the
register at REGAD.
mdc
mdio
Z Z 1 1 1 0 1
IDLE 32 bits ST
PRE
1-Gigabit Ethernet MAC v8.5 User Guide
UG144 April 24, 2009
-- DISCONTINUED PRODUCT --
STA

Figure 8-5: Typical MDIO-managed System

PRE Preamble
ST Start of frame
OP Operation code
PHYAD PHY address
REGAD Register address
TA Turnaround
shows a write transaction across the MDIO, as defined by OP='01.' The
STA drives MDIO
0 1 P4 P3 P2 P1 P0 R4 R3 R2 R1 R0 1 0 D15
OP PHYAD REGAD

Figure 8-6: MDIO Write Transaction

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MAC 1 MAC 2
mdio
mdc
MMD MMD
MMD MMD
MMD MMD
D13 D11 D9 D7
D14 D12 D10 D8
TA 16-bit WRITE DATA
D5 D3 D1 Z Z
D6 D4 D2 D0
IDLE
R
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