AM5718: Fails to enumerate over USB 3.0 when spread spectrum is enabled

Hello Peter,

Could you please share additional information about your environment

• What OS are you utilizing? SDK version?
• Is your Am57x board a TI board or a custom board?

Best,

-Josue

We are using Ubuntu Linux version 16.04 and processor SDK version  .

The processor is on a custom board that we developed.

Oops - left out the SDK version:  sdk-04.02.00.09

Hello Peter,

Short answer, I think figuring this out is non-trivial.

Lets start with software, from  the Linux perspective, USB 3.0 does not have SDK support. Please see the Build-sheet on our latest release. You are currently working with an SDK release from 2017, so please be advised that there will be very little to no support from us on software. I would even suggest to try newer software as a step  attempting to resolve the issue.

I believe historically this has been made to work on this device. Please see the following threads:

• https://e2e.ti.com/support/processors-group/processors/f/processors-forum/726126/am5728-usb-3-0-pll-spread-spectrum-setup
  This link includes the Compliance reports for both RX and TX
• https://e2e.ti.com/support/processors-group/processors/f/processors-forum/676452/am5718-usb3-0-spread-spectrum-clocking
  This thread has some guidance on how to get this to work properly including a suggestion to make sure all requirements and recommendations are followed correctly for layout of a new board in this document: SPRAAR7 
  
  

This last bullet would be my suggestion for next steps in this case.

I hope this helps. 

-Josue

Hi Josue,

We are working on updating the version of SDK. In the meantime, I have a question regarding the parameter PLL_SSC_CONFIGURATION2" - the value we have been using since Sept 2020 has been 0x0a008000. There is a TI support forum post that talks about this parameter and there are two values suggested for this parameter - 0x09b30a3d and 0x0800c800.

Do you have a recommendation on what this value should be?

Thanks

Peter

Hello Peter,

Unfortunately this is outside of my area of expertise, I have CC'd our USB HW engineer here in case he has any comments. Are you able to try both and see what works?

Hi Peter,

USB3.0 requires SSC to be enabled and is not optional like PCIe.

The SDK should be enabling the SSC for USB3.0 by default; and in case you have older SDK which may not be enabling it, the latest revision of the SDK should help.

If the SSC is not configured correctly or not enabled, then it will fall back to USB2.0 HS.