A Question for Verilog experts

[freqmax]

One could possible use an older FPGA like the XC4000 series. That are 5V compatible to replace or at least exploit as a realtime comparision to the real chip for development purposes.
However XC4000 and similar FPGAs are no longer sold. So it's to scavenge old graphics cards :-)
Btw, ATI CrossFire graphics card includes a XC3S400....
http://tinyurl.com/26empk

http://www.tomshardware.tw/940,review-940-9.html

[freqmax]

@alexh:
I/O inputs with a (5-3.3)/.010 = >170 ohm resistor in series?
The absolute maximum rating for any I/O is specified to 4.4 for Spartan-3. So your hack would likely rely on that 5V output is 0.6 volt lower than it's Vcc :-D

I'm going to read floppy discs with fpga (catweasel style) and need to interface the 5V Read-Data signal into the 3.3V FPGA. So I'm open for tips. The current solutions are:
1) Resistor with 2,7V zener in series. 3,3V output over the zener.
2) 74LV logics (or 74HC if I have to). Which is 5V tolerant but will happily deliver 3.3V compatible out.

Part of the problem is that the 1/0 threesholds for 5V and 3,3V are the same. But 5V have another 1,7V "ontop" that needs to be chopped away.

(Maximum for "0" is 0,8V ; Minimum for "1" is 2,0V)