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5.4
Reduced Gigabit Media Independent Interface (RGMII)
The IXF1104 MAC supports the RGMII interface standard as defined in the RGMII Version 1.2
specification. The RGMII interface is an alternative to the IEEE 802.3u MII interface.
The RGMII interface is intended as an alternative to the IEEE 802.3u MII and the IEEE 802.3z
GMII. The principle objective of the RGMII is to reduce the number of balls (from a maximum of
28 balls to 12 balls) required to interconnect the MAC and the PHY. This reduction is both cost-
effective and technology-independent. To accomplish this objective, the data paths and all
associated control signals are reduced, control signals are multiplexed together, and both edges of
the clock are used.
•
1000 Mbps operation – clocks operate at 125 MHz
•
100 Mbps operation – clocks operate at 25 MHz
•
10 Mbps operation – clocks operate at 2.5 MHz.
Note: The IXF1104 MAC RGMII interface is multiplexed with signals from the GMII interface. See
Table 16 "Line Side Interface Multiplexed Balls" on page 58
Figure 18. RGMII Interface
5.4.1
Multiplexing of Data and Control
Multiplexing of data and control information is achieved by utilizing both edges of the reference
clocks and sending the lower four bits on the rising edge and the upper four bits on the falling edge.
Control signals are multiplexed into a single clock cycle using the same technique. For further
information on timing parameters, see
Table 48 "RGMII Interface Timing Parameters" on page
Datasheet
Document Number: 278757
Revision Number: 009
Revision Date: 27-Oct-2005
®
Intel
IXF1104 4-Port Gigabit Ethernet Media Access Controller
TXC_3:0
TXD[3:0]_3
TXD[3:0]_2
TXD[3:0]_1
TXD[3:0]_0
TX_CTL_3:0
RXC_3:0
RXD[3:0]_3
RXD[3:0]_2
RXD[3:0]_1
RXD[3:0]_0
RX_CTL_3:0
Figure 37 "RGMII Interface Timing" on page 141
for detailed information.
TXC_3:0
TXD[3:0]_3
TXD[3:0]_2
TXD[3:0]_1
TXD[3:0]_0
TX_CTL_3:0
RXC_3:0
RXD[3:0]_3
RXD[3:0]_2
RXD[3:0]_1
RXD[3:0]_0
RX_CTL_3:0
B3203-01
141.
and
96
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