Electronic – Switch PCIe connections

connectorinterconnectpciestandardswitches

I'm trying to implement a PCI express switch; one lane from SoC and, two for mini PCIe ports. Something like the picture below.

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But I'm confused with the Tx and Rx connections, the transmitter should be connected with the receiver in every connection, right?

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But, the doubt occurs when in the reference schematics that I have for the switch, the connection in a male connector is Tx(of switch)-Rx(of port); like the picture above, and in a female connector is Tx(of switch)-Tx(of port); like the picture below.

enter image description here

Exists a sort of convention (standard or similar) for this kind of connection?

Best Answer

The signals are named from the point of view of the root complex, so anyone implementing a device that has an upstream facing port needs to be aware that they need to switch lanes.

I think it is a good idea to think independent from connectors here -- if you use PCIe internally on a single board, you have to swap, even if you don't have a male connector, and if you're building a riser card, you have a male connector but should not swap.

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