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Observer
Observer
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Registered: ‎03-05-2020

10GBASE-T SFP+?

Is there a Xilinx IP that can interface directly from the FPGA to a 10GBASE-T SFP+ module (such as on the vc707)? I'm finding it difficult to even understand what layer of the OSI model is implemented inside these SFP+ transceivers....is it the entire PHY? (LDPC PCS, PMA, AN) or is it just acting like a glorified ADC/DAC? I'm also finding it difficult to put a name and specification on the interface going to these modules: For the high speed stuff, they only have 1 tx pair and 1 rx pair. What is the data format?

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Xilinx Employee
Xilinx Employee
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Registered: ‎08-13-2007

I'd take a look at XAPP1305:

https://www.xilinx.com/support/documentation/application_notes/xapp1305-ps-pl-based-ethernet-solution.pdf

And the 10G Subsystem

https://www.xilinx.com/support/documentation/ip_documentation/xxv_ethernet/v3_2/pg210-25g-ethernet.pdf

But as quick simplification:

the Linux TCP/IP stack here implemented levels 4 & 3 of the OSI model. The MAC/10G Subsystem (which contains the MAC and the GT/transceivers for part of the PCS/PMD) implemented level 2 and part of level 1... And an external SFP+ 10G-BaseT module was used as well. The GTs can be used directly to interface to optical modules (e.g. 10GBase-R) or for some FPGA families a backplane (10GBase-KR) but you'll need an external transceiver (inside the SFP+ module here) for Base-T.

Cheers,

bt

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Explorer
Explorer
193 Views
Registered: ‎08-14-2013

The 10GBASE-T SFP+ would have an SFI or XFI interface facing the FPGA, accepting 64b/66b encoded data exactly the same as the 10GBASE-R wire format and performing all of the additional encoding and FEC required for 10GBASE-T.  You can think of the 10GBASE-T SFP+ as being a protocol converter between 10GBASE-R and 10GBASE-T.  From the FPGA point of view, it looks exactly the same as an SFP+ DAC cable or SFP+ optical module.