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USB Host HID Class Example for LPC2468

Eric Severson

Hello,

I am hoping to setup my LPC2468 to act as a USB Host and to work with the HID Class. I am wondering if anyone has suggestions on example code or reading material?

I have gotten Keil's USB HID Client working on my hardware, and have been looking through the Host Lite Mass Storage example provided by Keil/Nxp/OnChip.

Any suggestions would be greatly appreciated.

Thank you,
Eric

Parents
  • 0 in reply to Eric Severson

    Ah, okay, so I determined the problem: my client wasn't sending data (oops!). But this raises an interesting question:

    My understanding of the USB OHCI spec is that regardless of if a periodic (interrupt) IN endpoint receives data, it's TD will be processed, declared completed and placed on the done head. (ie, my understanding was that as soon as the Host Controller gets to servicing the periodic IN endpoint, it attempts a read from the USB client, and then regardless of whether or not the client had data to send, it would retire the TD to the Hcca->Done list).

    However, what appears to be happening is that the Host Controller does not decide retire the TD to the Hcca->Done list until some data actually comes in. So, since my USB client had no data to send, it appears that the IN TD was not being placed on the Hcca->Done list.

    Is this the way the OCHI USB HC is supposed to behave?

    Thank you,
    Eric

Reply
  • 0 in reply to Eric Severson

    Ah, okay, so I determined the problem: my client wasn't sending data (oops!). But this raises an interesting question:

    My understanding of the USB OHCI spec is that regardless of if a periodic (interrupt) IN endpoint receives data, it's TD will be processed, declared completed and placed on the done head. (ie, my understanding was that as soon as the Host Controller gets to servicing the periodic IN endpoint, it attempts a read from the USB client, and then regardless of whether or not the client had data to send, it would retire the TD to the Hcca->Done list).

    However, what appears to be happening is that the Host Controller does not decide retire the TD to the Hcca->Done list until some data actually comes in. So, since my USB client had no data to send, it appears that the IN TD was not being placed on the Hcca->Done list.

    Is this the way the OCHI USB HC is supposed to behave?

    Thank you,
    Eric

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