DS160PR810: TI Re-driver polarity swap with DS160PR810NJXR

Hi Ben,

This device is not aware of the polarity of the P and N lines. The method in Figure 1 (invert polarity on both RX and TX sides) is straightforward and should not have any problems, because the P line does not become an N line and vice versa. If the receiver calculates P - N it will still look the same as a normal case.

The method in Figure 2 (invert polarity on TX side only) will invert the polarity of the lane, so the differential P - N signal calculated by the receiver will be inverted from the normal case. I did some reading and the PCIe specification for receivers allows this inversion to be detected and compensated in the link training process. If your receiver is PCIe compliant, this method should still work, but in general I would recommend the first method because it should not need any corrections and fewer things can go wrong.

Best,

Evan Su