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Beginner
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Recommended procedure for FPGA clock forwarding

Hello,

 

I have an FPGA clock coming into my design.

I want to simply send this clock using another pin.

 

From working with other vendors - I learned that the recommended practice is to use an Output DDR Flip Flop for that purpose - as described in this link :

https://forums.xilinx.com/t5/Timing-Analysis/Why-ODDR-for-forwarded-clock/td-p/756737

 

Is this also the recommended practice for Intel FPGAs ?

 

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Employee
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Re: Recommended procedure for FPGA clock forwarding

Hi ,

In my point of view it depends upon your use case, if you want simple to give to an I/O pin you can directly hoke it up in RTL code and send the clock .

 

But if you need to route the clock in to global or any type of clock path, I will recommend to use the AltCLKCTRL ( alt clock control path) IP before giving to out put pin.

 

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Beginner
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Re: Recommended procedure for FPGA clock forwarding

Hi,

Is there an official Intel document that recommends ALTCLKCTRL for clock forwarding ?

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Employee
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Re: Recommended procedure for FPGA clock forwarding

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Beginner
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Re: Recommended procedure for FPGA clock forwarding

Hi,

I've read this document.

But couldn't find where it suggests to use the ALTCLKCTRL for the purpose of forwarding the clock as I asked.

If this recommendation exists in the document - please point me to it.

 

 

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Beginner
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Re: Recommended procedure for FPGA clock forwarding

This is such a simple request - I really don't understand why no one can provide a definitive answer to it !

I'll ask again.

Please point me to an official Intel document that states the RECOMMENDED procedure for forwarding a clock to an output pin.

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Employee
6 Views

Re: Recommended procedure for FPGA clock forwarding

Hi ,

May I know what device is it been using , i will send u the official document wiith respect to that device

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Beginner
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Re: Recommended procedure for FPGA clock forwarding

Arria V

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Employee
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Re: Recommended procedure for FPGA clock forwarding

Hi,

Kindly find the below document for your reference .

https://www.intel.com/content/dam/www/programmable/us/en/pdfs/literature/hb/arria-v/av_5v2.pdf#page=...

Page no: 102

 

Note:

These are the two documents in which Intel recommends the use of altclkctrl block .

 

 

 

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Beginner
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Re: Recommended procedure for FPGA clock forwarding

Hi,

I'm reading page 102.

It shows an option to use the ALTCLKCTRL block for clock muxing.

But I don't require clock muxing - so my question remains unanswered...

 

I have a SINGLE clock that's coming into an FPGA pin - I'm requirement to send it to an output pin.

What's the recommended procedure for that ?

 

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Employee
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Re: Recommended procedure for FPGA clock forwarding

Hi ,

Altclkctrl is the best approach and the above two documents are the only reference we have for your query .

I want to set the expectation that , I could not able to provide any more further details or writing other than the above document , apology to say that.

 

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Employee
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Re: Recommended procedure for FPGA clock forwarding

Hi ,

Let me know if you need further assitance

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