PCIe transmit preset config

Autonomous Machines Jetson & Embedded Systems Jetson AGX Orin
1

Hi

I’m using a Broadcomm PCIe net-card(pcie 3.0 x2) connected to Jetson Orin’s PCIe 14160000 node.
The netcard is ep and Orin’s pcie-c4 is RC.

I want to ask several questions about RC config in Orin:

  1. how to set RC’s(orin itself) transmit preset?
  2. how to set EP’s(the netcard mentioned above) transmit preset on Orin side?
  3. could you offer me a recommend configuration for pcie gen3 including preset, pre-cursor and post cursor?
2

Hi,

If you are designing a custom base board, then it means some adaptation configurations are needed.
Otherwise, your board may not work fine.

For Orin AGX series, you could refer to below document
https://docs.nvidia.com/jetson/archives/r36.3/DeveloperGuide/HR/JetsonModuleAdaptationAndBringUp/JetsonAgxOrinSeries.html?highlight=universal%20serial%20bus#jetson-agx-orin-platform-adaptation-and-bring-up
(please be aware that above link is for rel-36.3/jetpack6.0)

This document includes below configuration

  1. pinmux change & GPIO configuration
  2. EEPROM change as most custom boards do not have an EEPROM on it.
  3. Kernel porting
  4. PCIe configuration
  5. USB configuration
  6. MGBE configuration
  7. RGMII configuration

Thanks!

4

Hi

Thanks for reply.
I have checked the document you mention, but there has no hint about how to change transmit preset, pre-cursor and post-cursor.

5

What is the purpose for doing this? We have a PCIe driver running already, maybe you should refer to it first?

6

Broadcomm said that they prefer Orin’s RC tx preset setting to 7.
Refer to Orin’s Technical Reference, it seems to be 5 as default.

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7

Hi Teams，
Could you please advise on how to adjust the preset for PCIe Gen3? Is there a specific method available?
Additionally, what is the default preset value for PCIe Gen3 on the Orin side? Thank you!"