AM6442: PCIe REFCLK input in root complex mode

Thierry HAUSER

Part Number: AM6442

Tool/software:

Hello

In case of PCIE endpoint PCIe REFCLK is used as input only.

In case of PCIE root complex, thanks to this thread REFCLK can be as output on SR2.0 , but could it use as input only, respecting this kind of architecture (replace FPGA by AM64 ) ? :

Thanks for your feedback.

6 months ago

0 James Pair 6 months ago

TI__Intellectual 1385 points

yes, if FPGA (A&B) were replaced with AM64 (A&B) ; and both receiving same external Refclk as input, that would be OK.

0 Thierry HAUSER 6 months ago in reply to James Pair

Intellectual 400 points

Hello James,
So just to be 100% sure, AM64 is able to support PCIe REFCLK in root complex mode, isn't it?

0 Dominic Rath 6 months ago in reply to Thierry HAUSER

Mastermind 7480 points

Hello Thierry,

I'm not TI, but I've got some experience with AM64x and PCIe.

Having the PCIe reference clock as an input to both the AM64x as an RC and to the EP is the default on TI's AM64x EVM since revision A. On those boards there's a 100 MHz clock generator that feeds both the AM64x SERDES0_REFCLK0P/N as an input and provides the clock to REFCLK+- on the PCIe connector.

Only the earlier E2 revision connected the SERDES0_REFCLK0P/N directly to the PCIe connector, thus requiring the AM64x to provide the RefClk as an output on its pins.

Regards,

Dominic

0 James Pair 6 months ago in reply to Thierry HAUSER

TI__Intellectual 1385 points

Yes it is able to support

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AM6442: PCIe REFCLK input in root complex mode