CYUSB3304 + 2xCP2102N unkown usb device

[aldoc_3474881]

Hi. I'm using the CYUSB3304  hub and two CP2102N  usb to serial ICs. On a couple of the boards, i'm observing an error in Device manager "Unknown USB Device (Device descriptor request failed). Everything works properly, the two microcontrollers connected to the usb to serial devices are responding just fine.  I'm not sure if it's the HUB or the USB to serial giving the error... Any idea on what is happening?

Alin

[YangyangC_06]

Do you mean that CYUSB3304 is showing "Unkown USB device" in device manager?

Can you make a screenshot?

Meanwhil, try to download USB tree view at the link below to check the device informaiton.

https://www.uwe-sieber.de/usbtreeview_e.html

[aldoc_3474881]

Hi Yang. I am not sure if it's the HUB or the 2 serial to USB devices connected to the HUB which throw the error. I'm guessing it's the HUB. But everything works well.

Here is screenshot from USB tree viewer.

[aldoc_3474881]

Hi Yang,
Do you know what else I should try?

[YangyangC_06 · Accepted solution]

From the screenshot, the HUB enumerates well which shows no hardware defect on upstream path.

You could try to connect other USB devices to HUB(same port on HUB), Flash disk, mouse for example, to check if they all fails to enumerate.

If so, we could presume that hardware defect may exist on downstream path. If anything else could enumerate on this port of HUB, it shows something wrong with your USB device.