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Altera_Forum's avatar
Altera_Forum
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20 years ago

cyclone and 5V pci

Hi,

I have ask the question, but get no reply. So I ask again!

My pci add in card will be connected to PC motherboard. The PCI connector on common PC motherboard does not have the 3.3V PCI keys, so I think using buffers is better.

1), If having used buffers, which bank of EP1C6Q244 shall I use, bank1,3(with 3.3V PCI support) or bank 2, 4(without 3.3V PCI surpport, just 3.3V TTL)?

2), The PCI CLK length is 2.5inches. If using buffer chips, it means that the wire between PCI CLK pin and buffer chip is 2.5inches, or from PCIpin to EP1c6Q pin is 2.5inches?

Thanks,

eRen

1 Reply

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    20 years ago

    Keep in mind that modifying your PCI bus (5V -> 3.3V) may put you out of spec (PCI is pretty strict). If this goes into an end product and you need this to be up to spec I would look at that first before figuring out the implementation. Perhaps someone here can comment on this further or know if this will work (probably will work if done properly, not sure if you will meet the PCI spec though).