TUSB7320 polarity inversion

msmn

Other Parts Discussed in Thread: TUSB7320, TUSB7340

1) TUSB7320 PCIE_RX polarity
Can a customer invert the polirity of PCIE_RX?
Can PCIE_RXP and PCIE_RXN be swapped?

2) TUSB7320 PCIE_REFCLK
Can a customer invert the polirity of PCIE_REFCLK?
Can PCIE_REFCLKP and PCIE_REFCLKN be swapped?

3) If 2) is yes, is there a description or a definition about the PCIE_REFCLK polarity inversion in PCI Express Specification? For example, PCIE_REFCLK must automatically detect the inversion, register settings are needed to swap the polarity and so on.

over 11 years ago

0 Alexis Cortes9585 over 11 years ago

TI__Expert 4055 points

Hello Masumi,

We are reviewing your question and we will reply soon.

Best Regards,

Alexis Cortes.

0 Roberto Diaz over 11 years ago

TI__Genius 11255 points

Hello Saito.

As the PCIe specification points,

Support for Lane Polarity Inversion is required on all PCI Express Receivers across all Lanes independently (section 4.2.4.4.). But I would like to confirm that the TUSB73x0 support it.

Referring to the PCIE_REFCLK there is nothing on the PCI expect that comment that it can be swapped.

Regards,

Roberto

0 msmn over 11 years ago in reply to Roberto Diaz

Intellectual 805 points

Roberto,

1) According to the customer, the PCIE_REFCLKP and PCIE_REFCLKN are swapped on TI TUSB7320 EVM.

Is their understanding correct?

2) If the customer's understanding is correct, they would like to confirm that the swap is no problem.

Regards

Masumi Saito

0 msmn over 11 years ago in reply to msmn

Intellectual 805 points

Roberto,

Could you answer my questions?

Regards

Masumi Saito

0 Roberto Diaz over 11 years ago in reply to msmn

TI__Genius 11255 points

Hello Saito,

Sorry for the delay,

Yes the TUSB7340 support swap for the PCIE_REFCLKP and PCIE_REFCLKN signals and it should not cause any problem.

Regards,

Roberto.

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TUSB7320 polarity inversion