To make a board tolerant to the 5 volt pci spec most people add some small resistor to limit the current going into the pin. The 3.3V IO allow the card to talk to the bus. But the bus talking to the card will normally make the protection diode inside the pins of the chip to become active. Putting resistor will limit the current and protect the diode from destruction.
2012/11/8 michele <[email protected]>: > Sorry a little bit OT: > > I'm trying to build a simple and cheap pci board with a low cost fpga like > the machxo2 from lattice. > Now I'm having some hard time to figure out if this device is compatible with > 5 Volt pci or not. From the datasheet I understand that is compatible only > with > the 3.3 Volt implementation... But it looks like that specs are there to be > broken, and a lot of people (also lattice: check "latticeXP2 advanced > evaluation board") are just using those device on 5 Volt pci without a level > shifter or something similar. > > I'm a little bit confused. Any hint? > > Thank you > > Michele Carla' > > _______________________________________________ > Open-graphics mailing list > [email protected] > http://lists.duskglow.com/mailman/listinfo/open-graphics > List service provided by Duskglow Consulting, LLC (www.duskglow.com) _______________________________________________ Open-graphics mailing list [email protected] http://lists.duskglow.com/mailman/listinfo/open-graphics List service provided by Duskglow Consulting, LLC (www.duskglow.com)
