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Compact PCI and Hot Swap spec
there is a point in the hot swap spec for cPCI which is not clear to me.
The hot swap spec states that nearly all PCI signals have to be preloaded
to 1V during the board insertion process, before the pins make contact to
What happens, if you insert a board with a 64-bit bridge in a 32-bit wide
cPCI backplane? The PCI spec says that all 64-bit extension signals have to
be pulled up at the system slot (if supported) and slave boards that have
these signals unconnected must deal with floating inputs themselves. As
64-bit extension signals are also driven to 1V by the precharge circuitry
and not driven to a defined level by the backplane after the board has been
installed (as they are unconnected there), how is it possible to prevent
oscillation and current drain at input buffers, if they are kept at 1V?