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Package Loss befor chirp | Cypress Semiconductor

Package Loss befor chirp

Summary: 1 Reply, Latest post by aasi on 28 Feb 2014 08:03 PM PST
Verified Answers: 0
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SeeMe's picture
1 post

I'm working with the FX2 (CY7C68013A) in an FPGA application.
We are facing USB communication loss to the FPGA in Long term testing and i am now checking the USB communication on protocol Level.
I use a LeCroy protocol analyzer T2 Mercury.
What i see from the analyzer is, that the last packages befor the FX2 issues a K-Chirp are damaged.
The analyzer marks different error on these packaged: CRC16, CRC5, invalid package ID, …
But it’s always right in front of the K chrip. Anyhow the communication is not interrupted by these damaged packages.
Has anyone experienced such a behavior befor ? Is this a FX2 issue ? A analyzer issue ?
I also see this behavior with the FX2 demo board we bought.
Best regards,

aasi's picture
Cypress Employee
1166 posts

 I didn't quite understand your testing scenario. Why is FX2LP issuing K-Chirp in the middle of continous operation? Is it being reset or the host going through powercycling? Change in termination resistance happens during those handshakes so there is the possibility of the USB analyzer getting confused. More details on your test scenario would be helpful to understand what is happening.

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