Limit PCIe to one-way communication

Comments and questions to the author of the "Down to the TLP" posts (Eli Billauer)

Limit PCIe to one-way communication

Postby Guest » Fri Jan 12, 2018 5:27 pm


i am trying to figure out if it's possible to enable one-way communication over PCIe. This could be a Hardware solution, i.e. not connecting the RX ports - would the protocol still work?
Another, more elegant, solution i could imagine would be to configure PCIe to only communicate one-way - does it support such functionality?

In the end it doesn´t matter how to achieve it, the important thing is to guarantee that you can only communicate unidirectional. I was looking into the specification, but didn´t find a solution so far.

Can somebody here help me out?

Cheers Martin

Re: Limit PCIe to one-way communication

Postby support » Fri Jan 12, 2018 7:25 pm


First, what you can't do: Disconnecting the PCIe lanes in one direction will not work, as the underlying protocol is bidirectional. The PCIe link won't go up this way.

The immediate question is why you want one-way communication, between which entities and what kind of hardware you have at hand. For example, if you want a guaranteed unidirectional link between two PCs, based upon PCIe, you can use an FPGA with two PCIe units, and attach a Xillybus IP core to each. By connecting a stream between the two cores in the FPGA only in one direction, this gives you a reliable data stream of data (possibly several such).

A bit of shameless self-promotion, but hey, this is the Xillybus Forum...

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