🚀 go-pugleaf

luoni@jasper.mlb.semi.harris.com (Perry Luoni) writes:

>In article <1993Jan11.142553.5103@ips.cs.tu-bs.de> koch@eis.cs.tu-bs.de (Andreas Koch) writes:
>>Is it possible to physically destroy a Xilinx 3000 series LCA
>>by programming only (meaning: outside electrical parameters
>>are within valid bounds)? Since we are in the process of
>>establishing FPGA design labs, we would like to know if
>>we have to watch out for critical design flaws which would
>>endanger our LCAs. Any hints are appreciated!
>>
>>Andreas Koch
>>-- 
>>Andreas Koch                                Email  : koch@eis.cs.tu-bs.de
>>Institut f"ur theoretische Informatik       Phone  : x49-531-391-2384
>>Abteilung Entwurf Integrierter Schaltungen  Phax   : x49-531-391-5840
>>Gaussstr. 11                                Telex  : 95 25 26

>Yes, it is possible to short a lot of nodes together with the wrong data programmed into
>the LCA.  If you are using the Xilinx design software you don't have to worry about
>it though.  The software will prevent you from programming it wrong.  


We are worried about this too.  We have been told that as long as the
configuration only causes internal drivers to clash with each other, the
device will survive, but if you cause pin drivers to clash with other
devices on your board, the device can be permanently damaged.

We are not totally convinced that this is good advice.  We have seen a device
get _very_ hot with only internal contention.


By the way, the problem is not doing this at the design stage.  If you are
building 200 units a week using an LCA in a pqfp package, you are going to
get a percentage of boards that will not correctly load the LCA config
from the prom.  (this is most likely when you use the parallel prom mode)
We see our prototype get very hot when it can't read the prom correctly
and we are worried that we will have the LCA destroyed on each board that
has a fault that stops the config prom from loading correctly.

-- 
Scott Colwell				Labtam Australia Pty. Ltd.
net:	scott@labtam.labtam.oz.au	41 Malcolm Rd., Braeside
phone:	+61-3-587-1444			Melbourne, Australia  3195