AnsweredAssumed Answered

USB hub issue enumeration

Question asked by Fabrice DECROP on Jun 20, 2017
Latest reply on Jun 22, 2017 by Pavel Chubakov

Hi,

 

I'm facing an USB issue, wich does not appear systematically, but leads to no USB devices enumeration.

 

My plateform is based on P1010, using UTMI and on-chip PHY. I'm using EHCI controller.
P1010 is used in host mode, and is connected to a microchip USB2534 Hub.

 

My issue is a that the microchip hub is not enumerated at each boot of VxWorks 6.9.4.6.

 

My problem seems to come from missing SOF. They can be interpreted as a reset by the microchip hub, requested by the host controller. This reset leads to a false enumeration.

 

Following 3 files, with signal capture, and USB traces.
In good_start.jpg, we see the missing SOF. But is not reconised as reset by the hub. In this case, Hub is enumerated.

Good start
In bad_start.jpg, we also so see the missing SOF, but leading to my issue : hub goes to reset state, and then is not enumerated.

 

 

 

Bad start

 

 

In traces.jpg, we see a SOF error packet #70

USB traces

 

Could you please help me to solve this issue ? Do you know a workaround in order to have a good enumeration of USB devices at each boot ?

 

Thanks in advance for your reply,
Regards,
Fabrice DECROP

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