USB not operating

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user_1570836
Level 4
Level 4
50 replies posted 25 replies posted 25 sign-ins

Hello,

I have severe problems getting USB peripheral of PSoC5 to work. Attached are schematics and layout of my board design.

Whatever I burn into MCU, nothing works...my application, any changes to it, USB-UART CDC example. This I believe rules out  software problems. Device simply cannot be detected by computer at all. If I hard-reset USB data-line by applying external pull-up, unknown device is detected.

I have replaced MCU, ESD protection IC, series resistors, no change. I have sacrificed Cypress USB-BLE dongle's MCU, before unsoldering it was working fine. After moving to my board, it does not work.

If I disconnect computer, and burn firmware outputting clock on USB data-lines, I do not see clean square-wave (impedance mismatch to scope probe?), but I can definitively see correct frequency.

 

Now my question, what is happening there? I need this board to work correctly ASAP, but I am running out of ideas what to check.

Thanks in advance,

Stanislav

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user_1570836
Level 4
Level 4
50 replies posted 25 replies posted 25 sign-ins

Okay, solved. I have got 22MOhm resistors instead of 22Ohm. And additionally a faulty USB connector.

Lesson: Don't think of over-complicated causes and solutions. Sometimes the most simple occurs.

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