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PCI Express and Slow Back end Applications

by shmueld / January 27, 2008 12:58 AM PST

I am new to PCI Express. Could someone please explain to me how slow back end applications should interface to the PCI Express bus. We have bought a PLDA core that appears to do writes to the backend logic in Burst mode @125MHz. At the same time it expects the read cycle from the back end logic to be taken care of with a DMA access ! What is the best way to manage these types of accesses ? We need to interface this bus to a Dual Port Ram that runs at 20 Mhz.

How do other applications handle this type of speed ? Do all applications that interface to the PCI Express bus use DMA and Burst mode types of accesses ?

Is there anyway to forces the PCI Express accesses to do single address accesses ? (Yes I know this will slow things down a lot !?) Or is the nature of PCI Express only ever to do high bandwidth accesses which can only be implemented through DMA and burst modes ?

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you're in the wrong forum
by ramarc / January 27, 2008 1:06 AM PST

this site is intended for general pc users. you won't get much help with programming device drivers and low-level hardware interfaces.

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by R. Proffitt Forum moderator / January 27, 2008 1:23 AM PST

I did some stuff with old PCI. But even back then we could do plain old byte i/o and nothing demands you implement DMA, etc. Given the light reading I've done on PCIe I suspect the same is true.

-> But given the nature of what we are discussing you should get a member on the team to handle this area.


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