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Ixiasoft
Visible to Intel only — GUID: yrt1632169781855
Ixiasoft
5.3. Implementing a RS-FEC Direct Design in the F-Tile PMA/FEC Direct PHY Intel® FPGA IP
To istatiate a RS-FEC diect desig, follow the steps metioed i sectio Istatiatig the F-Tile Refeece ad System PLL Clocks Itel FPGA IP. I additio to the PMA data path paameteizatio, a RS-FEC diect desig allows you to eable the RS-FEC mode fo fowad eo coectio i a NRZ o PAM4 desig cofiguatio.
The RS-FEC optio i F-Tile PMA/FEC Diect PHY Itel® FPGA IP suppots the RS-FEC modes specified i sectio FEC Achitectue. Also efe to F-Tile Suppoted FEC Modes ad Compliace Specificatios fo a compehesive list of RS-FEC modes i the F-Tile PMA/FEC Diect PHY Itel® FPGA IP. Additioally, efe to sectio FEC Placemet Rules fo ules to follow whe cofiguig a RS-FEC diect desig.
I the RS-FEC tab of the F-Tile PMA/FEC Diect PHY Itel® FPGA IP, you select the Eable RS-FEC to cofigue a desig with FEC as show i the followig figue.
Based o the RS-FEC mode ad data ate fo you desig, you alig the PMA paallel clock fequecy ad choose the System PLL fequecy accodigly. Esue that the System PLL fequecy you choose i the F-Tile PMA/FEC Diect PHY Itel® FPGA IP aligs with the F-Tile Refeece ad System PLL Clocks Itel® FPGA IP efeece clock fequecy.
Thee ae additioal optios that you ca eable fo you RS-FEC desig. To eable the loopback select the Eable RS-FEC loopback optio. You ca also eable the Eable RS-FEC data iteleave patte optio. Whe you eable this optio, the RS-FEC laes ae bit-iteleaved o each physical lae by 64/80 bits. The default value is Off.
Whe you eable the RS-FEC featue i you desig, the TX ad RX deskew logic is eabled. Refe to sectio Deskew Logic fo moe ifomatio about the deskew logic i the TX ad RX datapath.
I a FEC diect desig, duig eset sequecig, afte tx_am_ge_stat is asseted, stat sedig the aligmet makes ad asset tx_am_ge_2x_ack afte two aligmet makes ae set. The tx_am_ge_stat goes high as pat of the eset sequece, befoe tx_eady is asseted. I additio, i the FEC diect mode, you ca pace the TX data valid sigal with the tx_cadece sigal.
Fo example, i the 100G FEC diect desig, the aligmet make (AM) cycle is 81920 clock cycles ad the AM pulse width is 5 clock cycles wide. I additio, the TX data is uscambled. If a FEC diect desig does ot lock o alig, the RX data is zeo.
FEC Mode | AM Pulse Width (Numbe of Cycles at IP Iteface) |
---|---|
25G | 4 |
50G | 2 |
100G | 5 |
128GFC, 200G, 400G | 2 |
32GFC | 1 |
64GFC | 2 |
Whe FEC is cofigued i 200G o 400G vaiat modes, you should ot scamble o descamble the data as this is doe by the RS-FEC had IP. I all othe FEC cofiguatios, such as 25G, 50G o 100G, you have to scamble the iput data ad you have to descamble output data.