3 Replies Latest reply on Oct 29, 2018 4:47 AM by anks

    PSoC 4200L CY8C4246AZI-L433 stops communicating through USB.

    user_391234561

      Hello, I am using a PSoC 4200L CY8C4246AZI-L433 in a USB application.  We have been shipping this product out for almost a year now and it has been working great.  Recently, our customer has encountered problems with some units in which the USB interface stops working.  I evaluated this issue for a couple of months now and I managed to capture the failure using a USB protocol analyzer.  What I found is that the USB host is continuously initiating USB Input transactions and the PSoC keeps responding with a NAK, since it has no data to send.  However, at some point in time, the host initiates another Input transaction and the PSoC simply stops responding.  The host keeps sending the Input transactions but, the PSoC will no longer respond.  I did verify that the PSoC is still operating properly.  The transactions from the host are happening pretty fast, is it possible that the PSoC is unable to keep up with the transactions?  I could go into a long description of all the things that I tested but, all that accomplished was to prove what it is not the cause.  One thing that I will say is that if you put a high-speed hub in between, the problem goes away however, a full-speed hub does not fix it.  Any help would be greatly appreciated.