Alternative PCIe configuration for Jetson Agx Orin 64gb

Robotics & Edge Computing Jetson & Embedded Systems Jetson AGX Orin
1

Hello!

I need to connect three FPGAs to a Jetson AGX Orin, please consider the Industrial Module. The Jetson specification defines a compatibility with “Up to 2 x8 + 1 x4 + 2 x1”. So, theoretically we have 6 PCIe controllers, right? However, the design guide describes the supported configuration, and I didn’t understand if those are the all supported configurations.

For example, I would like to connect TWO x4 PCIe devices to UPHY1 interface (Compatible with 1 x8), and ONE x4 to UHPY0, is it possible?

There is a similar topic (Splitting PCIe x8 into 8 times x1), and the answer was “There are no 8 pcie controllers”, but in my case, I would use only 3 controllers.

If I can’t “split” a x8 into two x4, I would be able to use the x8 as x4 only, and ignore the other lanes?

4

Hi,

Yes, there are 6 controllers available on Orin AGX and you can enable them all.

But they would only work as the pattern suggested by design guide doc. It has nothing to do with the number of controllers there. The controller can only control specific lane too.

For example, UPHY1 could only be a x8 confiugraiton. It cannot be 2 x4.
And C7 controller could only be on UPHY2 but cannot change to control UPHY1.

5

Hi, Wayne! Thanks a lot!

Is there any problem with using the x8 as x4?

6

You can use the x8 configuration but only connect 4 lane on it to make x4. This is supported.

8

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