PCI Output Buffer Design

[avt]

Hello guys,

I have to fiddle right now with the PCI bus and I`m reafding the spec.

I`m confused about some issues which are not realy explained why they are inthe way they are in the PCI-spec.

Could someone here please explain me why a 22 ohm load is assumed for the load (or the other way round for the source sid termination) of the output buffer. The trace and stubs should as far as I figured out have both 60-100 ohm.

Is here anybody who knows some good background literature about the line driver / receiver spec of the pci bus including transmission line effects.

Is there somewhere in the net some source where it`s shown how a pci output buffer is implemented ? (not just an ibis-model)

regards,

avt

 

[alok_ky]

the source and the load termination resistors are normally given as a part of the protocol. These values are decided based upon the waveshape/SI requirements on a proposed circuit board.
These values are decided by hte protocol designers.