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USB hosts hubs transceivers Forum Discussions

daryabeliakova
Level 2
Level 2
10 replies posted First like received 10 sign-ins

I am designing a usb hub using CYUSB3314-88LTXC HX3.

Im currently experiencing two issues:

1. My goal is to connect the hub (usb a upstream)  to a usb c port. When I use a usb c to a usb a cable to connect to the hub, the hub defaults to usb 2.0. However, when I use a usb a to usb a cable the hub acts as a usb 3.0. For my application, i would like to be able to connect the hub to a usb c port as a usb 3.0 device. 

 

2.  One of the downstream ports is a usb c 3.0. I'm connecting a camera that uses usb 3.0, however this also defaults to usb 2.0 exclusively. Note: this downstream port intentionally only uses one side of the usb c connector, we are not requiring this to work on both sides.

 

Is there an issue with the way the connectors are wired ?

 

Im attaching the schematic for reference. 

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1 Solution

 

Hi Darya,

Thanks for the update. Please check with the cable manufacturer to see if it supports USB SS.

Please find my comments below for the Schematics:

  1. Connect the decoupling capacitors and bulk capacitors connected as per Figure 2 of the Hardware design guidelines document. Ferrite beads connected did not serve the purpose. For more details on Ferrite bead usage refer to page 4 of the Hardware design guidelines document
  2. Provide all DS ports with 150-µF bulk capacitors
  3. Power-on-Reset RC components should meet the minimum reset time of 5ms(In your circuit it is less than 1ms)
  4. If HX3 is not used as Embedded Hub/ACA DOCK, we recommend you to add the VBUS_DETECT circuit as per the USB Specification
  5. If you are using an Internal ROM configuration(MODE_SEL = b'11), then you can remove the EEPROM from your circuit as it is not used in your use case.

Please follow our HX3 Hardware design guidelines document while designing a hub with HX3.

Thanks,
Ajeeth

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24 Replies
Ajeethkumar
Moderator
Moderator
Moderator
250 sign-ins 50 solutions authored 10 likes received

Hi,

Thanks for posting in Infineon Developer COmmunity!

  1. HX3 Hub will enumerate with both HS and SS USB devices. As you said, when you use Type-A to Type-A cable, the HX3 hub works, this means that the HX3 hub works as expected. I would recommend you check if Type-C to Type-A cable supports USB SS.
  2. If it is intended to work with only one side of the USB-C connector, I don't see any issue there. Did you try both orientations of the type-c connector for USB-SS support? As you shorted USB2.0 data lines of both rows of the type-C connector, USB 2.0 will work on any orientation but SS will work only in one orientation. But considering a receptacle, I would recommend you add support for both orientations of the Type-C receptacle. Please refer to this KBA for your reference.

I couldn't see the complete schematics(For example Power and decoupling, MODE_SEL, Reset circuitry, etc.). Is it properly connected as per Hardware Guidelines? I would recommend you follow the Hardware guidelines while designing the HX3 hub.

Thanks.
Ajeeth

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Hi Ajeeth,

 

Thank you for the prompt response! 

1. I've double checked and the color inside the usb casing is indeed blue so it should be capable on SS. Is there anything else I can check for?

2. Originally, we decided not to connect the rest of the ss lines on the usb c to avoid using a mux. Since it is set up to work as a single sided usb receptacle, I've tried to plug in the camera both ways but no avail. Is there anything I should be watching out for? 

We are set up to use internal ram. Im attaching the full usb hub schematic below.

 

Thank you,

Darya 

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Hi Darya,

Thanks for the update. Please check with the cable manufacturer to see if it supports USB SS.

Please find my comments below for the Schematics:

  1. Connect the decoupling capacitors and bulk capacitors connected as per Figure 2 of the Hardware design guidelines document. Ferrite beads connected did not serve the purpose. For more details on Ferrite bead usage refer to page 4 of the Hardware design guidelines document
  2. Provide all DS ports with 150-µF bulk capacitors
  3. Power-on-Reset RC components should meet the minimum reset time of 5ms(In your circuit it is less than 1ms)
  4. If HX3 is not used as Embedded Hub/ACA DOCK, we recommend you to add the VBUS_DETECT circuit as per the USB Specification
  5. If you are using an Internal ROM configuration(MODE_SEL = b'11), then you can remove the EEPROM from your circuit as it is not used in your use case.

Please follow our HX3 Hardware design guidelines document while designing a hub with HX3.

Thanks,
Ajeeth

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daryabeliakova
Level 2
Level 2
10 replies posted First like received 10 sign-ins

Hi Ajeeth,

Thank you for your recommendations! We have updated all of the capacitors and will be making revisions per hardware guidelines.

Per your suggestion, I checked with the manufacturer and the cable I bought is a USB 3.0 SS cable. However I had to further modify it to make the usb hub work as a usb 3.0 device. Im attaching a diagram of the standard cable and how I modified it. We are looking for a off the shelf cable solution that would allow us to use this hub at SS, is there anything you can recommend ? 

Thank you,

Darya

 

 

 

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Hi Darya,

For Upstream, as per USB specification, we recommend using a Type-B connector.

Please refer to the following KBAs to know more about converting Legacy ports to Type-C ports.
1. Termination Resistors Required for the USB Type-C Connector – KBA97180
2. Termination Resistors for Type-C to Legacy Ports – KBA97272
3. Replacing Standard USB 3.0/2.0 Connector with Type-C Connector - KBA228953

Any cable that supports SS Type-B to Type-C cable can be used. I found one Type-C to Type-B cable that supports SS. You can use this cable if needed.

Thanks,
Ajeeth

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daryabeliakova
Level 2
Level 2
10 replies posted First like received 10 sign-ins

Hi Ajeeth,

 

Im still struggling to get the USB c downstream connector to work. 

Things I've done since the last post:

Change CC resistors: 10k,22k,56k

Use a USB c to USB a super speed cable

Use a USB c to USB c super speed cable

Test to make sure my camera is 3.0 Device  ( attaching the device manager images from both cases )

Confirmed continuity from hub to downstream port to device

In Device Manager, I see the hub as a superspeed hub however any device that I attach to the downstream port is a USB 2.0 only.

Im attaching the layout images, can you please take a look at them to see if theres something preventing superspeed from working on the downstream port?

 

Thank you,

Darya

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Hi Darya,

Did you update your board revision based on our recommendations? If yes, please attach the updated schematics here.

Please provide the layout in Altium format.

Thanks,
Ajeeth

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Hi Ajeeth, 

Im working on updates for the next revision. Specifically the connector update and voltage filtering. 

We are hoping to work out the previous bugs and identify the cause of USB 3.0 downstream failure, prior to sending out a revision of the design. We use cadence for our designs, I can provide the board file or gerber files? 

 

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Hi Darya,

As per my Schematic review comments(my response on ‎Mar 03, 2022, 09:47 AM IST), Comment#1 can cause SS signal deterioration and this might be the root cause of the issue. 

Please follow our HX3 Hardware design guidelines while designing the schematics and layout with HX3.

Please attach the board files.

Thanks,
Ajeeth

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daryabeliakova
Level 2
Level 2
10 replies posted First like received 10 sign-ins

Hi Ajeeth,

Thank you for the helpful comments and suggestions! I am working on updating the schematic with all of the suggestions and hope to have it done by Friday morning. Per your suggestion, I am working on adding the mux to be able to use both sides of usb c. I was able to export the board file into Altium format. Can you please take a look at the usb hub super speed routing and let me know if it looks sufficient? 

Im attaching the layout below.

Thank you,

Darya

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Hi Darya,

Please find my review comments below:
1. It is recommended that the SS signals be routed in a single layer. Vias introduce discontinuities in the signal line and affect the SS signal quality.
2. HX3 HS and SS trace length should be less than 11 inches.

Thanks,
Ajeeth

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Hi Ajeeth,

Thank you, I will try to implement that in the new layout! 

Im attaching the updated schematic below. Ive updated the decoupling and added the mux per your suggestions.  I used KBA218460 for more details on SS mux control. Do you think the SS should work now on on both upstream and downstream ports?

Thank you,

Darya

 

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Hi Darya,

Please find my schematics review comments below:
1. Use 150uF Bulk capacitor for all DS ports
2. Use AC decoupling capacitors of 0.1 µF on the SS TX lines
3. Remove EEPROM as you are using Internal ROM configuration(if not needed in future)
4. Connect CC lines of the Type-C receptacle to the Mux to detect the connection orientation.
5. Provide 1uF capacitor and ferrite bead for US port VBUS
6. If you are using pin-strap, strap VID[2:0] to 1 as it is reserved.

You can refer to "Schematics and Layout Review Checklist" on Page 22 of HX3 Hardware design guidelines after completing your design.

Thanks,
Ajeeth

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Hi Ajeeth, 

Thank you for the comments ive made the updates to the schematic! We have updated the layout per hardware design guidelines, but because we are using a type c connector it was difficult to stay on single layer. Im attaching the layout below, can you let me know if this is ok? 

 

Thank you so much for all of your help!

- Darya

 

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Hi Darya,

Please find my layout review comments below:
1. Place the capacitor in reset circuitry close to the reset pin
2. SS traces should be provided with the guard traces along the USB data-trace with stitching vias. Please refer to Figure 26 in the HX3 Hardware guidelines document
3. Match the differential SS pair trace lengths within 0.12 mm (5 mils) and Hi-Speed (D+ and D–) signal trace lengths within 1.25 mm (50 mils)

Please refer to the "Routing of USB Data Lines" section in the HX3 Hardware guidelines document

Thanks,
Ajeeth

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Thank you Ajeeth,

These adjustments will be made! I appreciate the help! My final concern is I noticed that CYUSB4347 has cc line control so their design doesnt use a mux, is there any benefit to moving to that part or is it sufficient to continue to use CYUSB3314?

 

Thank you,

Darya

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Hi Darya,

If you are not using USB PD functionality and residing for HX3PD(CYUSB4347) only for CC functionality, you can stick to the current design if it serves the purpose.

If you wish to go with CYUSB4347(HX3PD), it would need a custom Schematic design. You can refer to this KBA for disabling PD functionality.

Thanks,
Ajeeth

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Ajeeth,

You are right, we don't have a need for PD. Thank you for clarifying that! 

Thank you,

Darya

Ajeeth,

My final concern with this revision is the guard traces/via stitching. We are using a plane as the guard traces, but current only keeping it where the SS traces are. Do you think it needs to be extended through out the whole board? Attaching the layout below. We did add stitching to all of the 2.0 traces. 

 

 

Thank you,

Darya

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Hi,

Usually, a layout consists of PWR and GND planes(throughout the whole board). For the layout which uses HX3 silicon, we recommend you provide a solid ground plane underneath. In addition to that, we recommend you add guard traces(in the same plane where SS traces were located) with stitching vias to the GND plane.

Thanks,
Ajeeth

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Ajeeth,

I'm seeing weird behavior on the TX lines of the downstream port. I'm attaching the images below. The yellow waveform is one of the tx lines and the blue is one of the rx lines for downstream port 3. This is taken during LFPS polling. It appears that the rx ( usb flash drive 3.0 ) is polling.  Is there something that could prevent the hub from LFPS polling and completing the link?

 

Thank you,

Darya

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Hi Darya,

Is the DS3 receptacle Type-C? If so, did you use SS Mux? Please check the orientation so that HX3 can detect the USB device Rx.

Did you follow our hardware guidelines?

Thanks,
Ajeeth

 

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Ajeeth,

We have made those changes for the new design but these are the test results from the current revision. We purchased a USB 3.0 analyzer and were able to see that the usb hub detects the rx termination but it doesnt send the signal needed to complete LFPS polling.

-Darya

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Hi Darya,

Thanks for the update.

Can you please share the latest schematics?

Are you facing this issue on all DS ports?

Please share the analyzer logs as well in addition to USB Signal waveform.

Thanks,
Ajeeth

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