Azhar Ali Chohan:
In a previous post I referred to the "PCI bus dynamic impedance thing". What I was talking about two things. In section 4.2 of the PCI Rev2.1 Spec they talk in detail about the issues of the driver circuit design of pin drivers for the PCI bus. It is complicated. The other thing is that there is a thing called Turn-Around which is required for a number of the bus signals that may be driven by various bus clients at different times. There is a controlled impedance way that this is done. The old way where one driver tristates and other goes on when it wants do not work with PCI.

All that said let me say that the whole subject of successfully interfacing a PCI peripheral is WAY beyond the scope of what can be handled via a few quick messages back and forth on this forum.

I can assure you that if you had a copy if the specification in hand (and I do) and you looked at it that that you would quickly stop thinking about connecting a PCI peripheral or card to your 8051.

You should go back and look at the post I left earlier in this thread on what methods are available to connect a microcontroller up to a PCI bus structure.

As far as the driver requirement....a PCI client has quite a number of programmable registers in its control circuitry. These require access and manipulation in order to successfully establish data transfer between an source and destination. Any software driver that operates a peripheral must deal with these registers. The PCI spec goes into quite some detail as to what each register and its respective bits are for. However the spec itself is not a direct roadmap to a successful implementation of talking to a device. For this reason it takes some good amount of work to get a device setup. One good this is that these registers, and in some cases acceptable subsets of them, are expected to be in every PCI bus client so once you get transaction initiation software written for one type of peripheral it will work with others with only a few mods.

However....I strongly sugggest that for 8051 stuff you stick to ISA boards and or peripherals that have the more standard bus interface on them.

You may have noticed that the perople who have worked on the 8051 type embedded web server applications have carefully chosen ethernet controllers that have standard busses on them........There is a strong hint there!