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USB Virtual COM Port problem

Rafael Risson

I'm using RL-USB CDC on a LPC2468 and I'm having this problem: http://www.keil.com/forum/19199/
I'm still not solucinar, does anyone know how to fix this?

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    When device re-connects while a PC application still opens the target COM port, usbser.sys fails. It is well-known problem of usbser.sys. I've answered on this problem at least a hundred times, everywhere. serenum.sys doesn't solve this problem, because the problem lies in the internal process in usbser.sys itself.

    PC application should always poll the existence of target COM port, so that it closes the COM port immediately when a CDC device disconnects. Unfortunately, RegisterDeviceNotification() doesn't work for usbser.sys. The PC app has to poll the COM port periodically, using SetupDi-APIs or using WMI.
    www.microchip.com/.../m575483.aspx

    Tsuneo

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  • 0

    When device re-connects while a PC application still opens the target COM port, usbser.sys fails. It is well-known problem of usbser.sys. I've answered on this problem at least a hundred times, everywhere. serenum.sys doesn't solve this problem, because the problem lies in the internal process in usbser.sys itself.

    PC application should always poll the existence of target COM port, so that it closes the COM port immediately when a CDC device disconnects. Unfortunately, RegisterDeviceNotification() doesn't work for usbser.sys. The PC app has to poll the COM port periodically, using SetupDi-APIs or using WMI.
    www.microchip.com/.../m575483.aspx

    Tsuneo

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