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Observer timi
Observer
1,063 Views
Registered: ‎08-09-2018

SSC support GTY Transceiver

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Hi,

I have a Kintex Ultrascale + device(KU3P) running a custom protocol @ 12.5 Gbit/s  8b/10b encoding.

Does the Transceiver support tx and rx spread spectrum clocking? 

The design is only for loopback(outside FPGA, only one FPGA) intended:

FPGA_TX(Pattern Generator) -> Custom ASIC -> FPGA RX(Pattern Checker)

If both TX and RX support SSC, is it sufficient to have one ssc oscillator for both tx and rx qpll ref clock?

Thank you.

 

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Xilinx Employee
Xilinx Employee
726 Views
Registered: ‎12-10-2009

回复: SSC support GTY Transceiver

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SSC support is defined in table 71 of DS922.  Both devices should use the same oscillator and it limited to the lower data rates.

In the advanced section on the GT Wizard the SSC settings can be chosen.

http://www.xilinx.com/support/documentation/ip_documentation/gtwizard_ultrascale/v1_7/pg182-gtwizard-ultrascale.pdf

http://www.xilinx.com/support/documentation/data_sheets/ds922-kintex-ultrascale-plus.pdf

 

 

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5 Replies
Moderator
Moderator
1,037 Views
Registered: ‎05-02-2017

Re: SSC support GTY Transceiver

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hi @timi,

 

thanks for contacting Xilinx forums .

 

from your query I believe and assume you would like whether spread spectrum clocking is supported on GTY transceivers on both  TX and RX .

 

yes is supported but only on the RX side for this information I would suggest you refer the Table 71: GTY Transceiver Receiver Switching Characteristics of the  ds922 .https://www.xilinx.com/support/documentation/data_sheets/ds922-kintex-ultrascale-plus.pdf.

 

let me know your inputs 

 

Chandra 

if your query is solved please close this thread by accepting the solution 

 

Regards
Chandra sekhar
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Observer timi
Observer
1,024 Views
Registered: ‎08-09-2018

Re: SSC support GTY Transceiver

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hi @csattar

thank you for the reply.

I thought I can just supply a ssc oscillator clock to the tx Transceiver ref clk and thereby generate the modulated jitter on the data!  So this not possible?

Since the Transceiver support different protocols(and ssc e.g. pcie) should it also support on the tx side?

Thanks

 

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Explorer
Explorer
779 Views
Registered: ‎07-10-2013

Re: SSC support GTY Transceiver

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timi,

While it is possible that using an SSC oscillator to produce the ref clk that the xcvr TX would use could work (due to the SSC frequency (presumably being 30-33KHz) being much lower than the xcvr PLL bandwidth (>1 MHz (presumably)), support for xcvr RX SSC on the incoming serial data is apparently much more of an issue.

Regardless of what DS922 appears to claim regarding SSC support, documentation for the US xcvr Wizard (PG182, v1.7) shows (p.87) that there is limited (i.e., no) support (officially) for anything other than 1.5, 3 and 6Gbps 8b10b SATA (or similar) protocols, at least if the timing of the incoming datastream is completely unrelated to the local ref clk timing (frequency and phase).  There certainly appears to be no (official) support for SSC RX for datarates of above 6Gbps, with even less support provided if the protocol is something other than 8b10b.

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Xilinx Employee
Xilinx Employee
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Registered: ‎08-07-2007

回复: SSC support GTY Transceiver

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hi @timi 

 

for tx side, it is also supported. i.e., if the ref clock is SSC modulated, then the tx output data is SSC.

assuming SSC is modulated at low frequency like 33Khz.

 

Thanks,

Boris

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Xilinx Employee
Xilinx Employee
727 Views
Registered: ‎12-10-2009

回复: SSC support GTY Transceiver

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SSC support is defined in table 71 of DS922.  Both devices should use the same oscillator and it limited to the lower data rates.

In the advanced section on the GT Wizard the SSC settings can be chosen.

http://www.xilinx.com/support/documentation/ip_documentation/gtwizard_ultrascale/v1_7/pg182-gtwizard-ultrascale.pdf

http://www.xilinx.com/support/documentation/data_sheets/ds922-kintex-ultrascale-plus.pdf

 

 

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