EP80579 Datasheet, PDF (1884/1916 Pages) Intel Corporation – Intel® EP80579 Integrated Processor Product Line

Intel^® EP80579 Integrated Processor
49.5.13.3.4 GbE Ethernet Interface — RGMII Mode Transmit Timings
Figure 49-35.RGMII 125 MHz Reference Clock Timing Diagram
GBE_REFCLK
T₁
T2
T₂
T₃
T₄
V_CC(80%)
V_CC(20%)
B6574-01
Table 49-76 shows the AC specifications.
Table 49-77. GbE Transmit Timing Values — RGMII Mode
Symbol
Parameter
Min
Nominal
Max
Units Notes
T₁
RGMII output clock period (1000 Base)
7.2
8.0
8.8
ns
1, 7
T₁
RGMII output clock period (100 Base)
36
40
44
ns
1, 7
T₁
RGMII output clock period (10 Base)
360
400
440
ns
1, 7
T₂
1000 base duty cycle with respect to T₁
(Nom.)
45
50
55
% 1, 3, 7
T₂
100/10 base duty cycle with respect to T₁
(Nom.)
40
50
60
% 1, 3, 7
T₃
Low to high rise time (20% to 80%)
T₄
High to low fall time (80% to 20%)
T₅
Data to clock output SKEW (at
transmitter)
-
-
0.75
ns 1, 4, 7
-
-
0.75
ns 1, 5, 7
-500
0
500
ps
2, 7
T₆
Data to clock output SKEW (at receiver)
1
-
2.6
ns
6, 7
Notes:
1.
This applies to the GBEn_TxCLK signal operating in RGMII mode.
2.
This applies to the GBEn_TXDATA[3:0] signals for RGMII mode.
3.
Duty cycle may be stretched/shrunk during speed changes or while transitioning to a received
packet's clock domain as long as minimum duty cycle is not violated and stretching occurs for no
more than three Tcyc of the lowest speed transitioned between.
4.
Measurement points for Rise time are 20% GBE V_CC to 80% GBE V_CC.
5.
Measurement points for Fall time are 80% GBE V_CC to 20% GBE V_CC.
6.
The RGMII specification v1.3 requires the board design to induce trace delay such that an additional
trace delay of greater than 1.5 ns and less than 2.0 ns is added to the GBEn_TxCLK signal between
the MAC output and the PHY input. This method would require “x-inches” of trace to routed for the
GBEn_TxCLK signal. Some PHYs solve this by supporting an internal delay within the PHY. Refer to
your chosen PHY data sheet for additional information on these clock delay modes.
7.
Guaranteed by design. These values are typical values seen for this process, but not measured
during production testing.
Intel^® EP80579 Integrated Processor Product Line Datasheet
1884
August 2009
Order Number: 320066-003US