SE1 on USB

[aniketmarkande]

Hi ,

Please find attached image.

Working on Kinetis K22 series controller and running USB stack on custom board.

I see in analyzer that periodically SE1 (single ended one) state appears for long time, which causing problems to run audio.

Any idea what might be the reason for SE1? and how to solve it?

Regards,

Aniket Markande

[mjbcswitzerland]

Hi

I think that you have SE0 and SE1 repeating (with some activity in between).
SE0 is a USB reset, initiated by the host (typically about 50ms in length) and SE1 is when the device signals to the host that it is there (not low speed).
The pattern looks to be a continues reset from the host or a continues reconnect from the device - is your board resetting all the time?

Regards

Mark

Kinetis: http://www.utasker.com/kinetis.html
Kinetis K22:
- http://www.utasker.com/kinetis/TWR-K22F120M.html
- http://www.utasker.com/kinetis/BLAZE_K22.html
- http://www.utasker.com/kinetis/BLAZE_K22.html
USB: http://www.utasker.com/docs/uTasker/USB_User_Guide.PDF
USB composites: http://www.utasker.com/kinetis/USB_Device.html
USB-CDC host<->device video: https://www.youtube.com/watch?v=XhISV1czIo4&list=PLWKlVb_MqDQFZAulrUywU30v869JBYi9Q&index=16

Free Open Source solution: https://github.com/uTasker/uTasker-Kinetis
Working project in 15 minutes video: https://youtu.be/K8ScSgpgQ6M

For better, faster, cheaper product developments consider the uTasker developer's version, professional Kinetis support, one-on-one training and complete fast-track project solutions to set you apart from the herd : http://www.utasker.com/support.html

[aniketmarkande]

Hi Mark,

i disconnected my laptop from AC adapter while debugging and SE1 condition did not appear. But instead of sending SOF every 1 ms there is gap of some ms where bus goes idle. (please check image)

Why bus is going idle instead of sending SOF although application is working properly(no reset), only hub is connected.

Regards,

Aniket

[aniketmarkande]

it was ground problem.

[aniketmarkande]

Hi Mark,

Thank you for quick response.

The board is not resetting every time.

I have connected only hub (no device) and captured the image when i posted the question. so i am not sure whats going wrong.

Also i read SE1 condition should not occur on USB bus. Please help me out to track the problem.

Regards,

Aniket