Virtex-4 Tri-Mode Embedded Ethernet MAC Wrapper v4.4
PCS, PMA, PMD
The combination of the Physical Coding Sublayer (PCS), the Physical Medium Attachment (PMA), and
the Physical Medium Dependent (PMD) sublayer comprise the physical layers of the Ethernet protocol.
Two main physical standards are specified for Ethernet:
• BASE-T, a copper standard using twisted pair cabling systems
• BASE-X, usually a fibre optical physical standard using short and long wavelength laser
BASE-T devices, supporting 10 Mbps, 100 Mbps, and 1 Gbps Ethernet speeds, are readily available as
off-the-shelf parts. As illustrated in
and
2,
these can be connected using GMII/MII, RGMII, or
SGMII to provide a tri-speed Ethernet port.
The Ethernet MAC has built-in 1000BASE-X PCS/PMA functionality and can be connected to a
RocketIO to provide a 1 Gbps fibre optic port, as illustrated in
Applications
Typical applications for the Ethernet MAC core include
•
•
Ethernet Tri-Speed BASE-T Port
illustrates a typical application for a single Ethernet MAC. The PHY side of the core is imple-
menting an external GMII/MII by connecting it to IOBs; the external GMII/MII is connected to an
off-the-shelf Ethernet PHY device, which performs the BASE-T standard at 1 Gbps, 100 Mbps, and 10
Mbps speeds. Alternatively, the external GMII/MII can be replaced with an RGMII (as shown) or as an
SGMII (which requires the use of a RocketIO). GMII, RGMII, and SGMII functionality are demon-
strated in the HDL examples provided with the example design.
Figure Top x-ref 2
Virtex-4 FX Device
Ethernet MAC
10 Mbps,
100 Mbps,
1 Gbps
Ethernet FIFO
GMII/MII
(or RGMII)
Switch or
Router
IOBs
MAC
Tri-speed
BASE-T
PHY
Twisted
Copper
Pair
10 Mbps,
100 Mbps,
1 Gbps
Figure 2:
Typical 1000BASE-T Application
DS307 February 15, 2007
Product Specification
3
XILINX [ XILINX, INC ]
