Was '[sdiy] FPGA Synth Music' - Damaging FPGA by an Incorrect UCF Setting ?????

[Scott Gravenhorst]

See inline at bottom...

Jason Tribbeck <Jason.Tribbeck at ascom.com> wrote:
>Hi,
>
>> > I did look at the 3A while designing it, but there was something in the
>> > datasheets about its power requirements using two supplies that I was
>> > unsure about - however, I can't remember what it was, but I think it was
>> > something to do with configuration.
>> 
>> I'm using an XC3S200AVQ100 on my current project:
>> 
>> http://members.cox.net/ebrombaugh1/synth/dsPIC_fpga/index.html
>
>I did see that, and was the reason for looking at the 3A. I did 
>spot you'd only used one regulator and wondered how :) 
>
>> It's working nicely. One of the advantages is that it's slightly cheaper
>> than the 250E I used on the previous project. The configuration issue you
>> may be thinking of is that there's a little parameter you need to insert
>> into the .UCF file to let the part know that it's being given 3.3V for
>> VCCaux. That's just so that the internal references know where to set the
>> thresholds on some of the I/O standards. Otherwise it works transparently
>> with only two supplies (3.3V & 1.2V).
>
>That was the issue - I wasn't sure what kind of damage would 
>occur if you'd accidentally forgotten that setting ;) 
>
>Which knowing my luck I would've done for the first board, and 
>then wondered if it was the schematic, layout or soldering that 
>I'd got wrong somehow because it had caused irreparable damage to 
>the chip, which would've put me off making any more boards. But 
>that's worst case scenario :) 
>
>I think I also had my 250Es by then as well - I've still got 3 
>left, so I'll wait for those to be used and then redesign the 
>board to take a 200A. -- Jason Tribbeck 

I've only used development boards so far, but there are all manner of different kinds of
settings available through the UCF.  I had never thought that I could actually damage the
FPGA by setting something incorrectly.  But Jason has got me thinking, I really do not
know...  

I am hopeful that Xilinx designed their FPGAs so that a simple goofed up UCF can't
actually blow out or physically damage the FPGA...  

Do I have reason to be concerned?



-- ScottG
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-- Scott Gravenhorst
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