HX3 Hub used as a USB 2.0 - Working as a Full Speed but does not enumerate as a High Speed device

[Nanda]

We are using CYUSB2304-68LTXI in our instrument. We have both USB Full speed and High Speed devices on the same hub.  On power up the USB Full speed devices are detected correctly but the USB High Speed devices are not identified correctly. 

There are 4 Hubs in total in the system. 10 instruments connected in total. Combination of both full speed and high speed devices.

Can you please shed some light why is the High speed device enumeration not happening.

[Ajeethkumar_P]

Hi Nanda,

Can you give the block diagram of your system for better understanding?

Did you follow our guidelines when designing the hub? If possible, can you share the schematics of your design?

Thanks,
Ajeeth

[Nanda]

Hi Ajeeth,

Thank you very much for your prompt response. Yes we have referred to the reference schematics, the application note as well. For the cypress chip we have created the IC as multi part configuration in the schematics. There are 3 ICs (Hub 0-2) which is a replica of the below configuration.

Part 1- Power Supply & USB Configuration

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Part 2 – No connects

[cid:image006.png@01D8E219.D7AF0160]

Part 3 – Clock,Reset and Memory.

[cid:image009.png@01D8E219.D7AF0160]

Part 4 – USB Power Control Enable
[cid:image011.png@01D8E219.D7AF0160]

Part 5 – Upstream and Downstream ports connections

[cid:image015.png@01D8E219.D7AF0160]

Switch Connection
[cid:image018.png@01D8E219.D7AF0160]

USB Port Connection

[cid:image020.png@01D8E219.D7AF0160]

The power supply used for 1.2V is the part which is used in the reference design. The 3.3V part is LT1764AEQ from ANALOG DEVICES.

Please let me know in case you observe any problem or any suggestions.

There is a combination of High Speed and Full Speed devices on the Hubs. All Full speed devices communicate well on the Hubs. But if I connect any High Speed devices are on the Hubs they do not communicate, independently as well.

Thank you,
Regards,
Nanda

[Ajeethkumar_P]

Hi Nanda,

I could not see the images correctly. If it is confidential, Please fill in Y/N/NA to the checklist on page 22 of our HX3 Hardware Guidelines App note.

Also, can you share your system's USB Tree View logs(Use the "Save XML Report" option)?

Thanks,
Ajeeth

[Nanda]

Hi Ajeeth,

Attached the schematics in pdf for your reference. Please let me know your inputs on tne same. The 3 Hubs are daisy chained and the HUB0 is connected to the Host PC.

Few questions:-

1. Does the upstream port need any kind of termination. I have seen that the HX3 has the termination resistor in built.
2. Is there any jumper option on the chip to enable the high speed USB.

It would be very helpful if you can shed some light on this problem.

Thank you,
Regards,
Nanda

[Ajeethkumar_P · Accepted solution]

Hi Nanda,

I could not see any attachments. Please attach the requested.

1. No. HX3 has internal termination resistors, which will be enabled on the data lines after detecting VBUS as per USB Specification.

2. No jumper options are needed. If you connect to the High-speed host, HX3 will automatically enumerate as a High-speed USB device.

Thanks,
Ajeeth