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PSoC 5, 3 & 1

Not applicable

Hello fellow developers 🙂

Using the PSOC 5, when connecting the USB to a PC the "USB UNKNOWN" message pops up.

1. I've used several designs with a usbuart feature. while on a different board the USB is recognized, on my board it isn't.

2. since my USB traces go through a VPX connector to another board and only then to a USB connector, I bypassed my board by attaching the USB cable straight to the 22.1 ohm resistors on both + and - pins (connected GND as well) - result was the same. UNKNOWN DEVICE.

3. I even replaced the device on my board from a 2015 date code to a 2017 date code, thinking that could be the problem.

So far I'm quite desperate.

Since I'm sure in my schematic, I think there are 3 issues that could be the problem:

1. I'm missing some kind of first time assignments to the device?

2. The burning in is somehow not correct (it says "successful" so i doubt it's the problem. but occasionally i get an error on first burn-in and succeed only in the 2nd try)?

3. I have some peripheral issues with voltages/currents/reset/capacitors/traces?

Can anyone assist? Have an idea on what I should check?

Thank you!


3 Replies
Valued Contributor II

I see this message if I use USBUART_3V_OPERATION

so I always set 5V:


Not applicable

Thank you!

I've checked and it was set for 5V.

Tried setting 3V but it was still recognized as unknown.

I want to try and use the driver here on the website because with the generated driver there's a notice that the driver doesn't match my device.

on a different board the same design works just fine.

Another thing is; all other features seem to work fine. I'm using the power monitor, debouncer for reset and even was able to read a temp sensor using I2C (through the JTAG interface).


any ideas on what to try??


Can you share the schematic of board, so that we can check.

Are you observing this enumeration issue even after after programming a Code Example based on USBFS