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USB Hosts Hubs Transceivers

JaMa_1550451
New Contributor II

I am helping debug a custom design that has 3 CY7C65642 on it.  There is one that is connected to the host, and then the other two are downstream from the top one.  This is a self-powered unit with the reset pin being driven off of the USB power.

   

My problem is that when I turn on the board, I can see the board enumerating properly on my Windows laptop and it reports the proper VID/PID (I am not using any EEPROM).  But then nothing happens (and GANG LED goes dark).

   

While probing the crystal feeding the main hub, I see it come up for about 500ms, and then go to ground.  This, along with the above, leads me to believe that the system is going into a suspend mode, but I don't know why.  The device continues to be enumerated in windows, so for some reason windows hasn't felt the need to disconnect it.

   

Any thoughts?  I've spent a couple of days on it and am at a loss at this point....

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2 Replies
AjayB_76
Employee

Hello.

   

Can you provide the snapshot of schematic? We can do a quick check and review it. If you think its confidential, you can create a technical support case and Cypress technical support team will evaluate them.

   

 

   
        
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JaMa_1550451
New Contributor II

Thank you for getting back with me.  After talking things over with a Cypress FAE, it appears that we had our CUR# pins pulled low (since the designer wasn't planning on monitoring the current), which apparently caused the lower devices to not enumerate.  Once we pulled those high through a pull-up resistor, everything worked fine.  Thanks again.

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