Reception Of The Odd Case - Xilinx LogiCORE 1000BASE-X User Manual

End of Frame Encoding
Note:
positive running disparity or a /I2/ if the frame ended with negative running disparity. This is illustrated
as the shaded code group.

Reception of the Odd Case

Figure D-8
serially using the RocketIO transceiver, or in parallel across the TBI, and translation of this
code-group stream into the receiver GMII. This is performed by the PCS Receive Engine.
Note that, as defined in IEEE 802.3 figure 36-7b, the combined /T/R/R/ sequence results
in the GMII encoding of Frame Extension. This occurs even in full-duplex mode.
Ethernet 1000BASE-X PCS/PMA or SGMII v9.1
UG155 March 24, 2008
The first Idle to follow the frame termination sequence will be a /I1/ if the frame ended with
gmii_txd[7:0]
gmii_tx_en
gmii_tx_er
tx_code_group
Figure D-7: 1000BASE-X Transmit State Machine Operation (Even Case)
illustrates the reception of the in-bound code-group stream, received either
rx_code_group
gmii_rxd[7:0]
gmii_rx_dv
gmii_rx_er
Figure D-8: 1000BASE-X Reception State Machine Operation (Odd Case)
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FCS
PCS Transmit Engine Encoding
FCS T R R I1/I2 I2
FCS T R R I1/I2 I2
PCS Receive Engine Decoding
FCS 0x0F
R
I2 I2
I2 I2
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