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Integration to provide sgmii functionality, Ethernet statistics core – Xilinx LOGICORE UG144 User Manual

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1-Gigabit Ethernet MAC v8.5 User Guide

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119

UG144 April 24, 2009

Ethernet Statistics Core

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Features of this configuration include:

Direct internal connections are made between the GMII interfaces between the two
cores.

If the GEMAC has been generated with the optional Management Interface, the
MDIO port can be connected up to that of the Ethernet 1000BASE-X PCS/PMA or
SGMII core to access its embedded configuration and status registers. See

“Using the

Optional Management Interface.”

Due to the embedded Receiver Elastic Buffer in the Ethernet 1000BASE-X PCS/PMA
or SGMII core, the entire GMII is synchronous to a single clock domain. For this
reason, userclk2 is used as the 125 MHz reference clock for both cores and the
transmitter and receiver logic of the GEMAC core now operate in the same clock
domain. This allows clock crossing constraints between the gtx_clk and
gmii_rx_clk

clock domains to be removed from the GEMAC UCF. See

“Timespecs

for Critical Logic within the Core.”

Integration to Provide SGMII Functionality

The connections between the two cores to provide SGMII functionality are identical to the
connections required for 1000BASE-X PCS and PMA using the device-specific RocketIO
transceiver. The only difference is that the Ethernet 1000BASE-X PCS/PMA or SGMII core
is generated with the SGMII option. See

“Integration to Provide 1000BASE-X PCS and

PMA using a RocketIO Transceiver”

for a description of SGMII integration.

Ethernet Statistics Core

The Ethernet Statistics core can be integrated in a single device with the 1-Gigabit Ethernet
MAC core. Using the Ethernet Statistics core lets you

Count statistics based on the rx_statistics_vector and
tx_statistics_vector

outputs from the MAC

Select 32-bit or 64-bit counters

Specify which statistics are counted and have precise control of the conditions under
which the counters are incremented

Read statistics optionally through the host interface of the GEMAC or independently
of the MAC

A description of the latest available IP Update containing the Ethernet Statistics core and
instructions on obtaining the IP update can be found on the

Ethernet Statistics product

page

.

Connecting the Ethernet Statistics Core to Provide Statistics Gathering

The Ethernet Statistics core interfaces directly to the 1-Gigabit Ethernet MAC core. The
Ethernet Statistics core takes in the tx_statistics_vector and
rx_statistics_vector

as inputs. Statistics values gathered can then be read out

through the Statistics core Management Interface, that can be shared with the MAC
Management Interface.