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USB Low-Full-High Speed Peripherals

New Contributor

I designed a new board using CY7C65211. My computer is Dell XPS 13 with Windows 10 Pro.

After installed CypressDriverInstaller_1.exe, I connected the board to USB port. I checked the Device Manger.

There is "Unknown USB Device (Device Descriptor Request Failed)". I did the manual point to download driver.

(Please see attached file for error.)

The error is still the same. Please educate me what I did wrong.

Million thanks in advance.

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1 Solution
Moderator
Moderator

Hello Noriaki,

Thank you for the response.

Denny,

Please find the below points that needs to be addressed in your schematic.

1. The VBUS line should have a 0.1uF decoupling capacitor (placed close to VBUS pin of USB-Serial IC) which is highly necessary for proper enumeration.

2. nXRES pin should not be left unconnected, It should be pulled high using a resistor if not used. Failing which the device may always be in reset and will not enumerate.

3. The I/O domain and core domain is powered using the VDDD pin (range: 1.71 to 5.5V). You can use the 1.8V regulated supply to the VDDD pin.

As mentioned in the datasheet, 1.71 V <= VDDD <= 1.89 V: Short the VCCD pin with the VDDD pin.

4. If the VDDD is powered to 1.8 V the VCCD should simply be shorted to VDDD as mentioned in my 3rd point.

5. VDDD should have 0.1 uF and 4.7uF decoupling capacitor to filter out the low and high frequencies.

Reference schematic:

pastedImage_10.png

6. Once the above corrections are made and the device is enumerated on the PC. Use the configuration utility to connect to device and check the box that says VDDD voltage is less than 2V, if you are using a 1.8 V supply to VDDD and program the device. Reconnect.

pastedImage_7.png

Thanks,

Yatheesh

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9 Replies
Moderator
Moderator

Hello,

In most cases this error is reported when the firmware on the device has issues or firmware is struck at a certain point during setup stage of enumeration.

Since USB-Serial device is a fixed firmware part, this is not a firmware issue. Looks like a problem on the hardware. 

Can you please share your board schematics for review?

Also, please let me know if you are facing the same issue on other ports of the same laptop and different laptops as well?

Thank,

Yatheesh

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New Contributor

Hello Yatheesh,

Thank you very much for your reply.

The design is copied from CY7C65211 document.

I attach a portion of the board design for your information.

Please let me know if you have questions.

Thank you very much for your support and patience.

Denny

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Employee

Which configuration in the datasheet did you copied from?

If you want to provide a power supply in your device, VBUS should be connected to 3.3V power supply.

GS004841.png

If you want to use a 1.8V power supply, the CY7C65211 should be configured first to use a 1.8V power supply.

GS004842.png

This configuration need an additional jumper to control the VDDD voltage.

In any case, VCCD pin is connected to a 1uF bypass capacitor which is used by the internal regulator.

Regards,

Noriaki

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Moderator
Moderator

Hello Noriaki,

Thank you for the response.

Denny,

Please find the below points that needs to be addressed in your schematic.

1. The VBUS line should have a 0.1uF decoupling capacitor (placed close to VBUS pin of USB-Serial IC) which is highly necessary for proper enumeration.

2. nXRES pin should not be left unconnected, It should be pulled high using a resistor if not used. Failing which the device may always be in reset and will not enumerate.

3. The I/O domain and core domain is powered using the VDDD pin (range: 1.71 to 5.5V). You can use the 1.8V regulated supply to the VDDD pin.

As mentioned in the datasheet, 1.71 V <= VDDD <= 1.89 V: Short the VCCD pin with the VDDD pin.

4. If the VDDD is powered to 1.8 V the VCCD should simply be shorted to VDDD as mentioned in my 3rd point.

5. VDDD should have 0.1 uF and 4.7uF decoupling capacitor to filter out the low and high frequencies.

Reference schematic:

pastedImage_10.png

6. Once the above corrections are made and the device is enumerated on the PC. Use the configuration utility to connect to device and check the box that says VDDD voltage is less than 2V, if you are using a 1.8 V supply to VDDD and program the device. Reconnect.

pastedImage_7.png

Thanks,

Yatheesh

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New Contributor

Hello Yatheesh,

Sorry for late reply. It is because our technician is out sick of 2 weeks.

Per your suggestion, I have added logic to nXRES. (Please see attached file for detail.)

After the technician made the change, I measured point B = 0.3V (low) before plugged in the USB cable.

After I plugged in the USB cable, I measured point B = 1.7V (high).

I checked the USB in Device Manager.

The following is error message:

     "Unknown USB Device (Device Descriptor Request Failed)"

We need to use the board 1.8V to supply VDDD.

Please let me know what I do wrong.

Million thanks for your support in advance.

Best regards,

Denny

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Moderator
Moderator

Hello Denny,

Please try the below:

1. Connect VBUS pin of the CY7C65211 device to the connector VBUS as before and add the decoupling capacitors (0.1 uF is sufficient).

    VBUS input range is 3.15 to 5.25,  so 1.8V on vbus will not work.

2. Pull up Xres pin to VDDD (1.8 V) using a resistor.

3. Short VCCD to VDDD directly as VDDD < 2V. Remove the bypass capacitors connected to VCCD pin. 

Please try the above.

Thanks,

Yatheesh

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New Contributor

Hello Yatheesh,

Thank you very much for your reply.

Will get back to you as soon as possible.

Million thanks for your support and patience.

Best regards,

Denny

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New Contributor

Thank you, Yatheesh.

Your recommendation works great.

I would recommend you include your recommendation in the CY7C65211 specification. It will help the future users.

Million thanks for your support and patience.

Denny

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Moderator
Moderator

Thank you!

Regards,

Yatheesh

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