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Newbie simon@bosch
Newbie
339 Views
Registered: ‎04-18-2019

LVDS input timing spec of Spartan 7

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Hi Xilinx support team,

We are currently implementing "LVDS conversion to MIPI" (LVDS input, MIPI HS & LP output) on a Spartan 7 FPGA.

Could you tell me where I can find the LVDS input timing specs, especially setup & hold time?

Is it the one listed in Table 23 of DS189 document?

 

Sincerely,

Simon

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Scholar jmcclusk
Scholar
314 Views
Registered: ‎02-24-2014

Re: LVDS input timing spec of Spartan 7

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Those are the nominal setup/hold times, but in the absence of other timing paths, they don't mean much.   You need to set an input timing constraint and run a timing analysis to actually see this being applied in context.

Read Chapter 5 of UG906, and all things shall become clear.

 

Don't forget to close a thread when possible by accepting a post as a solution.

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3 Replies
Scholar jmcclusk
Scholar
315 Views
Registered: ‎02-24-2014

Re: LVDS input timing spec of Spartan 7

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Those are the nominal setup/hold times, but in the absence of other timing paths, they don't mean much.   You need to set an input timing constraint and run a timing analysis to actually see this being applied in context.

Read Chapter 5 of UG906, and all things shall become clear.

 

Don't forget to close a thread when possible by accepting a post as a solution.

View solution in original post

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Scholar drjohnsmith
Scholar
309 Views
Registered: ‎07-09-2009

Re: LVDS input timing spec of Spartan 7

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LVDS is just a voltage e/ current specification, it has no timming informaotin.
<== If this was helpful, please feel free to give Kudos, and close if it answers your question ==>
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Scholar drjohnsmith
Scholar
307 Views
Registered: ‎07-09-2009

Re: LVDS input timing spec of Spartan 7

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You need to either as mentioned, use th etools,

 

or by hand, add the LVDS propergation delay from the tables, to the routing dleay for th erout you want to use, to the setup time of the register you want to use, allowing for the clock route...

 

Stay with the tools,,

Rember, the tools meet your spec and stop,

    so you need to put a timming constraint on to see if you meet timing,

        no constraint and you get what ever the tool stoped at.

 

 

<== If this was helpful, please feel free to give Kudos, and close if it answers your question ==>
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