End of Frame Encoding

R

Note: The first Idle to follow the frame termination sequence will be a /I1/ if the frame ended with positive running disparity or a /I2/ if the frame ended with negative running disparity. This is illustrated as the shaded code group.

gmii_txd[7:0]

FCS

gmii_tx_en

 

gmii_tx_er

 

PCS Transmit Engine Encoding

tx_code_group

FCS

T R R I1/I2 I2

I2

I2

 

Figure D-7:1000BASE-X Transmit State Machine Operation (Even Case)

Reception of the Odd Case

Figure D-8illustrates the reception of the in-bound code-group stream, received either 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.

rx_code_group

FCS

T R R I1/I2 I2

I2

I2

PCS Receive Engine Decoding

gmii_rxd[7:0]

FCS

0x0F

gmii_rx_dv

gmii_rx_er

Figure D-8:1000BASE-X Reception State Machine Operation (Odd Case)

Ethernet 1000BASE-X PCS/PMA or SGMII v9.1

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UG155 March 24, 2008

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