XC9572XL bus hold - Cant be disabled

Jul 17, 2007 2 Replies

No matter what options I use, the bus hold circuits are enabled on the inputs of a XC9572XL (same problem with 95144XL) in a design of ours. I've tried ISE6.3 and WEBPack 9.1, no difference.



The reason I want high impedance inputs is that they are used with a high value series resistor (and clamp diodes) as part of a power MOSFET out-of-saturation short circuit protection.



If anyone has experience with this or especially how to solve it I would be very grateful...



Peter Wallace


Look for UG445

Uwe Bonnes bon@elektron.ikp.physik.tu-darmstadt.de Institut fuer Kernphysik Schlossgartenstrasse 9 64289 Darmstadt --------- Tel. 06151 162516 -------- Fax. 06151 164321 ----------

tried

I seem to remember you have to open the advanced options **after** compiling in the fitter tool where you get the option to set the default pin state; unfortunately, I seem to recall you can't set it to Hi-Z or input (F***ing stupid).

I don't have the tool open now, but I had the same problem a while ago. Once you compile, the options magically appear - amazing, even if you can't make it do what you want.

Cheers

PeteS

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