Xilinx 1000BASE-X - Manual (Page 55)

Ethernet 1000BASE-X PCS/PMA or SGMII v9.1 www.xilinx.com 55
UG155 March 24, 2008
Designing with the Client-side GMII for the 1000BASE-X Standard R
Normal Frame Reception with Extension Field
In accordance with the IEEE 802.3, clause 36, state machines for the 1000BASE-X PCS,
gmii_rx_er
may be driven high following reception of the end frame in conjunction with
gmii_rxd[7:0] containing the hexadecimal value of 0x0F to signal carrier extension.
This is illustrated in Figure 5-4 . See Appendix D, “1000BASE-X State Machines” for more
information.
This is not an error condition and may occur even for full-duplex frames.
Frame Reception with Errors
The signal gmii_rx_er when asserted within the assertion window signals that a frame
was received with a detected error (
Figure 5-5 ). In addition, a late error may also be
detected during the Carrier Extension interval. This is indicated by gmii_rxd[7:0]
containing the hexadecimal value 0x1F, also illustrated in
Figure 5-5 .
Figure 5-4: GMII Normal Frame Reception with Carrier Extension
gmii_rxd[7:0]
gmii_rx_dv
gmii_rx_er
preamble FCS
SFD
0x0F
Figure 5-5: GMII Frame Reception with Errors
gmii_rxd[7:0]
gmii_rx_dv
gmii_rx_er
preamble FCS
SFD
0x0F 0x0F
0x1F
error during frame error during extension