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Visitor
Visitor
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Registered: ‎08-23-2017

Ultrascale 100G Ethernet IP over QSFP28 on VCU108

Hi,

I have a VCU108 which has QSFP28 and CFP2 ports. I have seen examples using the 100G Ethernet IP hard core over the CFP2 on VCU108, but not QSFP28.

Has anyone used the 100G Ethernet IP core over the QSFP28 interface? Can the 100G Ethernet IP core be used over the QSFP28 interface?

Thanks,

Raymond

 

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Adventurer
Adventurer
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Registered: ‎11-06-2018

Hi @rchan ,

 

I haven't used this 100G Ethernet IP for QSFP+, but you should be able to do so, because both of them use GTY. However, even if you do so, QSFP+ on VCU108 can only give you 28Gbps (UG1066).

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Registered: ‎01-08-2012

I've used the Ultrascale 100G Ethernet IP hard core with both CFP4 and QSFP28.  CFP4 has basically the same interface as your CFP2 (assuming CAUI-4).

Differences between CFPx and QSFP28 that might affect your design:

  1. QSFPxx lacks a "signal detect" / "loss of signal" output pin.  I assume the wrapper you have written for for your 100G core takes a signal detect input.  You will have to use software to poll the I2C registers in the QSFPxx to determine the signal detect status, and somehow send that information to your FPGA IP core.
  2. QSFPxx lacks a "laser enable" input pin.  You may have to use software to write to an I2C register in the QSFPxx to turn the (four) lasers on (assuming it isn't on by default).
  3. QSFPxx has a "LPMode" input pin.  This has to be in a particular state (low) before the QSFPxx will work.
  4. QSFPxx has a "ModSelL" input pin.  This has to be in a particular state (low) before the QSFPxx will communicate over I2C.
  5. QSFPxx has a "ResetL" input pin.  This has to be in a particular state (high) before the QSFPxx will work.

 

I've never used a VCU108, so I can't comment on that.

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Visitor
Visitor
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Registered: ‎08-23-2017

I think the 28Gbps in UG1066 is the max. throughput per lane, and a QSFP has four lanes in total to yield 100G. This appears in the standard of QSFP28+.

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