I upgrade my cPCI board to an adlink-3970 (PCI 3.0). The machine boots up to windows, all the drivers are installed correctly including the my PCI 2.1 device's driver (meaning the CPU was able to read the ROM over the PCI bus). However, when I try reading data from my PCI 2.1 device, all the registers read 0. Are these two boards not compatible?
More info: I've read that they should be compatible and the electrical/mechanical specs indicate that they are. I've also tried swapping in for another CPU board but with the same results. The only difference in the upgraded board is that the CPU uses a PCIe-PCI bridge to communicate on the PCI bus. I'm wondering if that's the issue.
PCIe is backward compatible. A PCIe3.0 card will work on a PCIe2.0 slot.