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LPC2148 USB HID

How to change report size in USB HID class. I would like to change ReportSize(8) to ReportSize(12) but the error has occur.
Can I chage ReportSize to 12 bit? Now I use only one Enpoint. if I woule like to use many Enpoint.
How to change code?
How about data rate? more or same only one endpoint.

0 Tsuneo Chinzei over 17 years ago

Are you talking about the KEIL HID example?
"LPC2148 USB HID (Human Interface Device) Example"
http://www.keil.com/download/docs/306.asp

"Can I chage ReportSize to 12 bit?"

See this chapter of the USB HID spec.
6.2.2 Report Descriptor (HID1_11.pdf p24)

"Device Class Definition for HID 1.11" from USB.org
www.usb.org/.../HID1_11.pdf

BYTE InReport[2];        // HID Input Report, low-byte first

/* HID Report Descriptor */
const BYTE HID_ReportDescriptor[] = {
  HID_UsagePageVendor(0x00),
  HID_Usage(0x01),
  HID_Collection(HID_Application),
    HID_UsagePage(HID_USAGE_PAGE_BUTTON),
    HID_UsageMin(1),
    HID_UsageMax(3),
    HID_LogicalMin(0),
    HID_LogicalMax(1),
    HID_ReportCount(1),        // <--- number of fields
    HID_ReportSize(12),        // <--- bits
    HID_Input(HID_Data | HID_Variable | HID_Absolute),
    HID_ReportCount(1),
    HID_ReportSize(4),         // <--- padding to the byte boundary
    HID_Input(HID_Constant),
    HID_UsagePage(HID_USAGE_PAGE_LED),
    HID_Usage(HID_USAGE_LED_GENERIC_INDICATOR),
    HID_LogicalMin(0),
    HID_LogicalMax(1),
    HID_ReportCount(8),
    HID_ReportSize(1),
    HID_Output(HID_Data | HID_Variable | HID_Absolute),
  HID_EndCollection,
};

"Now I use only one Enpoint. if I woule like to use many Enpoint."

HID interface consists of
- ONE interrupt IN EP
- ONE interrupt OUT EP (optional)

If you want to use more EPs, apply composite device configuration.

"How about data rate?"

The maximum speed of HID is 64 byte/ 1msec USB frame on Full-Speed (FS) bus, on each endpoint. See these posts.

"LPC2148 usb controller"
http://www.keil.com/forum/docs/thread11137.asp
"LPC2148HID"
http://www.keil.com/forum/docs/thread11135.asp

Tsuneo