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Visitor jbeesoniq1
Visitor
3,301 Views
Registered: ‎09-29-2008

Skipping Spartan6 IODELAY2 Cal

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Hi,

 

If I simply want to dynamically walk through the 256 delay taps rather than choose one static value, can I *not* perform the calibration (and not provide IOCLK)?  For example, I would like to treat the IODELAY2 as an async delay to deskew some signals to improve margin... much like I could do with Virtex4/5/6 (there a 0->31 or 0->61 range).  The signal I wish to allow some deskew on has a bitrate is less than 188Mb/s as required for cal.

 

In this case, I do not care what the actual per-tap delay is, only that I can walk through dynamically adding up to a max delay of X... where (30% of 13.568ns) <= X <= 13.568ns (for speed grade -1).

 

Thanks!

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Teacher eteam00
Teacher
4,057 Views
Registered: ‎07-21-2009

Re: Skipping Spartan6 IODELAY2 Cal

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If I simply want to dynamically walk through the 256 delay taps rather than choose one static value, can I *not* perform the calibration (and not provide IOCLK)?

 

There are only two variable delay modes for IODELAY2, and both require calibration.  This is described (with astonishing clarity) in UG381 section "I/O Delay Modes".

 

Don't blame me, I'm just conveying the bad news.

 

-- Bob Elkind

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2 Replies
Teacher eteam00
Teacher
4,058 Views
Registered: ‎07-21-2009

Re: Skipping Spartan6 IODELAY2 Cal

Jump to solution

If I simply want to dynamically walk through the 256 delay taps rather than choose one static value, can I *not* perform the calibration (and not provide IOCLK)?

 

There are only two variable delay modes for IODELAY2, and both require calibration.  This is described (with astonishing clarity) in UG381 section "I/O Delay Modes".

 

Don't blame me, I'm just conveying the bad news.

 

-- Bob Elkind

SIGNATURE:
README for newbies is here: http://forums.xilinx.com/t5/New-Users-Forum/README-first-Help-for-new-users/td-p/219369

Summary:
1. Read the manual or user guide. Have you read the manual? Can you find the manual?
2. Search the forums (and search the web) for similar topics.
3. Do not post the same question on multiple forums.
4. Do not post a new topic or question on someone else's thread, start a new thread!
5. Students: Copying code is not the same as learning to design.
6 "It does not work" is not a question which can be answered. Provide useful details (with webpage, datasheet links, please).
7. You are not charged extra fees for comments in your code.
8. I am not paid for forum posts. If I write a good post, then I have been good for nothing.

View solution in original post

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Visitor jbeesoniq1
Visitor
3,296 Views
Registered: ‎09-29-2008

Re: Skipping Spartan6 IODELAY2 Cal

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Hi Bob,

 

True, a good bit of clarity, it was more a question of omission.  The cal sets the max tap, but if you don't cal I was hoping the max would be defaulted to 255 so I could simply dynamically walk the 0 -> 255 range.

 

Thanks!

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