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LPC2148 HID

Joseph Joseph

Hello,

I'm trying to understand this code "LPC2148 USB HID (Human Interface Device) Example".

After enumeration an interrupt is always generated (for Endpoint IN 1). Then the report is sent to the PC.

Why? How could i stop it?


thanks,
Joseph

  • 0

    "How could i stop it?"

    place a bear trap in front of it? just watch out if a real bear falls into it, he's sure to be angry:)

    sorry, no idea what you are talking about. Please provide more information about what you are doing. A web link to the app note you are refering to would help

  • 0 in reply to Andy Curda

    Hi,
    I am using Keil USB HID code. I have modified it for a custom HID device which does not need to send data continuously to host (alike mouse which sends data to PC continuously).
    Datasheets says when a packet is successfully transferred to host from any IN endpoint, an interrupt is generated & if no data is available for transfer, this data request also generates an interrupt (See LPC214x user manual UM10139 page 198, first 5-6 lines). In my custom HID application, I dont want this interrupt. I tried using Set Mode command, but interrupt is always generated.
    Hope this is enough info. Thanks in advance.

  • 0 in reply to Sadhoo Baba

    Hi,
    I had a similar issue with LPC2378 and I solved it by using the feature reports on the control endpoint.

    I'll be more clear:
    the data are continuously sent to the host because the host itself is requesting them periodically.
    This happens because the device defines an input report which, by its nature, is supposed to be requested by the host periodically on the IN endpoint 1.
    You can overcome this problem by replacing the input report with a feature report which will be conveyed on the IN endpoint 0.
    The host will now poll the IN endpoint 0 only after a specific request coming from the application (for instance, if the host application is written for windows with visual studio you'll have to use the function HidD_GetFeature - for more information have a look at the link msdn2.microsoft.com/.../ms790913.aspx).

    Hope this helps.

    Sebastiano