Intel IXF1104 - Manual (Page 78)

Intel
®
IXF1104 4-Port Gigabit Ethernet Media Access Controller
Datasheet 78
Document Number: 278757
Revision Number: 009
Revision Date: 27-Oct-2005
by the user. The RGMII interface supports operation at 10/100/1000 Mbps when a full-duplex link
is established, and supports 10/100 Mbps when a half-duplex link is established. The GMII
interface only supports a 1000 Mbps full-duplex link.
5.1.5.1 Speed
The copper MAC supports 10 Mbps, 100 Mbps, and 1000 Mbps. All required speed adjustments,
clocks, etc., are supplied by the MAC. The operating speed of the MAC is programmable through
the
“MAC IF Mode and RGMII Speed ($ Port_Index + 0x10)" (MAC_IF_Mode). The IXF1104
MAC speed setting must be programmed by the system software to match the speed of the attached
PHY for proper IXF1104 MAC operation.
Note: When the IXF1104 MAC is configured to use the GMII interface, the only mode of operation that
is supported is 1000 Mbps full-duplex.
If 10/100 Mbps operation is required in either full-duplex or half-duplex, the IXF1104 MAC must
be configured to use the RGMII interface.
5.1.5.2 Duplex
The MAC supports full-duplex or half-duplex depending on the line-side interface that is
configured by the
“MAC IF Mode and RGMII Speed ($ Port_Index + 0x10)" (MAC_IF_Mode).
The duplex of the MAC is set in the “Desired Duplex ($ Port_Index + 0x02)” on page 163 . The
IXF1104 MAC duplex setting must be programmed by the system software to match the attached
PHY duplex for proper IXF1104 MAC operation.
5.1.5.3 Copper Auto-Negotiation
In the copper MAC, auto-negotiation and all other controls of the PHY devices are achieved
through the MDIO interface, and are independent of the MAC controller. See
Section 5.5, “MDIO
Control and Interface” on page 99 for further operation details.
Note: In copper mode, auto-negotiation is accomplished by the attached PHY, not the IXF1104 MAC.
Thus, the IXF1104 MAC does not automatically configure the MAC or other blocks in the device
to be consistent with attached PHY auto-negotiation results. This must be accomplished by the user
and system software.
5.1.6 Jumbo Packet Support
The IXF1104 MAC supports jumbo frames. The jumbo frame length is dependent on the
application and the IXF1104 MAC design is optimized for a 9.6 KB jumbo frame length. Larger
lengths can be programmed, but limited system performance may lead to data loss during certain
flow-control conditions
The value programmed into the “Max Frame Size (Addr: Port_Index + 0x0F)" determines the
maximum length frame size the MAC can receive or transmit without activating any error counters,
and without truncation.
The “Max Frame Size (Addr: Port_Index + 0x0F)" bits 13:0 set the frame length. The default value
programmed into this register is 0x05EE (1518). The value is internally adjusted by +4 if the frame
has a VLAN tag. The overall programmable maximum is 0x3FFF or 16383 bytes.