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USB Low-Full-High Speed Peripherals

New Contributor

YatheeshK_36RajathB_01

Hi , this s sabitha here , am working on cypress usb to dual uart ic ( cy7c65215a) , I configured this ic in self powered morde i.e vbus supply 3.3v given seperately and vccio is also given 3.3v . now the problem is usb not detected i dono why?????, In usb connector first pin deccoupled through 0.1uf, Please give me the suggestion

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Moderator
Moderator

Hello,

Can you please let me know what changes did you do to the previously shared schematic?

Please check the below:

1.  When VBUS on the CY7C65215A is powered and not connected to the host, is the DP line pulled up to 3.3V? If no, then the USB PHY is not being powered. Try to power the VBUS pin using 5V and  check for enumeration. If it enumerates, disable the VBUS regulator by checking the box in the USB-Serial configuration utility that says "VBUS voltage is 3.3V" and then try with 3.3V.

pastedImage_0.png

2. If the DP line is pulled high, then there might be problems in the signal quality which causes failure in enumeration. Please let me know if this is the case? Also, please share the USB protocol logs when the device is connected. If you do not have an hardware protocol analyzer, please share the Wireshark pcap logs. 

Thanks,

Yatheesh

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9 Replies
Moderator
Moderator

Hello Sabitha,

Please let me know if you are using a custom board or replacing the IC on CYUSBS236 DVK?

If you are using a custom board, please share your board schematics for review.

Thanks,

Yatheesh

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New Contributor

Hi Yethees,

Thanks for your quick response

I hereby attached my custom design. I have referred the datasheet pg no.19

Regards

sabitha M

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Moderator
Moderator

Hello Sabitha,

Can you please let me know if the device manager refreshes after plugging the board to the PC and if there is any device additionally found in the device manager, ether under the Universal Serial Bus controller section or Other devices section. If yes, please select the properties of the device and share a screenshot.

You can also check the activity using Wireshark pcap capture to find if there is any descriptor request sent by the host and response by the device.

If you do not find any devices under the device manager then follow the below schematic changes steps.

1. Replace the 1.5uF by-pass capacitor connected to the VCCD pin with a 1uF and check for the enumeration in the device manager.

2. Remove the 4.7 uF capacitor connected close to the to the VBUS pin and check for enumeration in the device manager.

Thanks,

Yatheesh

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New Contributor

Hi,

Thanks for your support , Could you please tell me whether my design is correct or not

Regards

Sabitha M

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Moderator
Moderator

Hello,

The following changes are recommended to the design.

1. 1uF  capacitor bypassed to gnd on the VCCD pin.

2. Rest circuit as below to maintain a minimum of 1us time constant.

pastedImage_0.png

Thanks,

Yatheesh

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New Contributor

Dear sir

I have changed but no changes in that. in DP & DM pin voltage levels are in 0V while am connecting usb connector to PC

Regards

Sabitha M

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Moderator
Moderator

Hello,

Can you please let me know what changes did you do to the previously shared schematic?

Please check the below:

1.  When VBUS on the CY7C65215A is powered and not connected to the host, is the DP line pulled up to 3.3V? If no, then the USB PHY is not being powered. Try to power the VBUS pin using 5V and  check for enumeration. If it enumerates, disable the VBUS regulator by checking the box in the USB-Serial configuration utility that says "VBUS voltage is 3.3V" and then try with 3.3V.

pastedImage_0.png

2. If the DP line is pulled high, then there might be problems in the signal quality which causes failure in enumeration. Please let me know if this is the case? Also, please share the USB protocol logs when the device is connected. If you do not have an hardware protocol analyzer, please share the Wireshark pcap logs. 

Thanks,

Yatheesh

View solution in original post

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New Contributor

Hi

Thank you very much for your quick response , My device is working fine .USB detected ,when DP line Pulled-up to USB Supply through 1.5K resistor.

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New Contributor

Hi

After plug-in my device device manager does not refreshes,and also additional no devices found.

Regards

Sabitha M

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