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Visitor erili347
Visitor
2,142 Views
Registered: ‎05-31-2010

Serious issue using IMPACT 11.4

Hi all! my first message on the board..

 

 

My problem:

 

When programming my xc3s250e using impact 11.4 and Platform cable USB II it sometimes after programming gets extremely hot. Cannot touch it with my fingers without burning. Powering off and on the fpga-board and trying again doesnt help, same thing, gets hot when programmed.

 

The solution to this problem is to restart IMPACT. Then it will program as normal. Using the same bit file.

 

This problem happens about 1 in 100 programming. Offenly when impact has been running for a whole working day. So, this leads me to the conclusion that this is an impact issue.

 

I would really like to inform xilinx about this issue.

Anyone else who have experienced this?

 

BR,

Erik Lindahl

Actiwave AB

Sweden

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1 Reply
Scholar austin
Scholar
2,116 Views
Registered: ‎02-27-2008

Re: Serious issue using IMPACT 11.4

Erik,


Obviously, there is something very, very wrong.


Impact is not the problem, however.  This part family is now more than 4 years old, and if this was a problem, it would have exploded here into a full scale emergency response.  Given that I have never heard of this happening, it doesn't seem that Impact is to blame.

 

Impact will not program a part with the wrong bitfile (it will error out, and tell you it can not program the part), corrected since the Virtex E/Spartan 2 days.  Back then, you could get a high current condition programming a smaller part with a bitfile intended for a larger part.

 

Which power supply is supplying the current when it gets hot, Vccint, Vccaux, or Vcco?  Remember this, we will return to it later.


Much more likely is that the part has latched-up.  This is known as SCR crowbar or  latch-up, and is caused by injecting more than 200 mA of current into (or drawn out of) the IO's.

 

Check the programming voltage.  Is it 2.5v or 3.3v?  Which is it supposed to be?  Check the IOs, what are they doing when this latch-up occurs?

 

If this is latch-up in the IO banks, this will be drawing excessive current from Vcco.  If this is a ESD zap (below) or a Impact programming cable voltage issue, the current may be going into Vccaux.

 

Another possible cause is ESD:  if you have discharged ESD into the part, it may be now damaged, and much more prone to latch-up.

 

Last, were there any DRC violations when the bitfile was built in bitgen?  Look at the log files (this last comment is extremely unlikey to be the issue, but in the interest of full disclosure, I mention it here to always check you bitgen warnings).

 

 

Austin Lesea
Principal Engineer
Xilinx San Jose
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