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19.0
Gigabit Ethernet (GbE) Interface
The EP80579 Gigabit Ethernet Media Access Controller (GbE MAC) is based on Intel's
fourth generation gigabit MAC. The GbE MAC provides a standard IEEE 802.3 Ethernet
interface for 1000BASE-T, 100BASE-TX, and 10BASE-T applications. The controller is
capable of transmitting and receiving data rates of 10/100/1000 Mbps.
Through the GbE MAC interface, EP80579 can be connected to an external PHY, which
can support Reduced Ethernet (RMII) and Reduced GMII (RGMII).
The GbE MAC includes a single Management Data Interface (MDI)- Management Data
Input/Output (MDIO) and Management Data Clock (MDC). The single Management
Data Interface is used to communicate, control, and configure the PHY devices
interfacing to the GbE ports.
Finally, each GbE MAC is capable of self-configuration via an optional, external serial
EEPROM. A single EEPROM is used for all the GbE MACs.
Note:
The EP80579 can support both 3.3V and 2.5V PHY for the GbE interface. The media
outputs will use 2.5V drivers that are 3.3V-tolerant. This is a violation of the RMII
specification, which calls for TTL level outputs (not LVTTL) and 5V input level tolerance.
We expect all major PHY devices that may be used in a EP80579 system will drive a
maximum voltage of 3.3V.
RGMII version 1.3 is specified as a 2.5V CMOS level I/O interface and as such, EP80579
is fully compliant. RGMII version 2.0 is specified as a 1.5V HSTL I/O interface and the
EP80579 is NOT compliant with this standard. All PHY devices that the EP80579 may
be used with are expected to support RGMII version 1.3 standard. The MDIO, MDC, and
serial EEPROM bus will be implemented with 2.5V I/O drivers.
19.1
GbE MAC/LAN Interface Interconnect
The GbE MAC connects to an external LAN component to provide the GbE LAN
capabilities. The GbE MAC bus master capabilities enable the component to process
high level commands and perform multiple operations, which lowers IA-32 core
utilization by offloading communication tasks from the IA-32 core.
The GbE MAC supports several PHY components, depending on the target market. This
chapter's design guidelines are provided using the Marvell* GbE Transceivers (e.g.,
Marvell Alaska Quad* 88E1141/88E1145 (Quad-Port) Transceiver) as the LAN PHY
component.
EP80579 GbE MAC and the LAN PHY component.
Note:
Intel recommends that you consult the EP80579 Software Documents in the
"Technical Documents" section at the Intel website (
) to determine if the Ethernet Physical Layer device (PHY) you intend to
soc
use in your design has software driver support. Utilyzing Physical Layer
devices already supported by the software driver set will alleviate additional
code for PHY configuration and management .
®
Intel
EP80579 Integrated Processor Product Line
Platform Design Guide
209
®
Intel
EP80579 Integrated Processor Product Line—Gigabit Ethernet (GbE) Interface
Figure 135
and
Figure 137
provide the interface interconnect between the
http://www.intel.com/go/
Order Number: 320068-005US
May 2010
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