Re: USB NAK events continuously received

Bassman59a_at_yahoo.com
Date: 12/31/04

  • Next message: starfire: "Re: Details on PIC" 
    Date: 30 Dec 2004 15:59:07 -0800

    dereklai2k@yahoo.com.hk wrote:
    > Hi,
    >
    > Recently I have a project which needs to interface usbn9603 with
    MCU.
    > At PC side the XP can recognize the device as a HID device without
    > problem. However, I have traced the MCU program that it continuously
    > receive NAK events at end point 3. The endpoint 3 is enabled to
    > transfer data in initialization stage. However, I have not run any
    > program at the PC side.
    >
    > Is it normal? Thanks!

    Yes, it sounds like the host is polling according to the rate set in
    the HID's endpoint descriptor. If the device isn't ready to return any
    data to the host, it NAKs.

    -a

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