USB HID reports longer than 64 bytes on lpc2141

Report Descriptor
This report descriptor defines 191 bytes Input and 150 bytes Output report

#define INREPORT_SIZE    191
#define OUTREPORT_SIZE   150

/* HID Report Descriptor */
const BYTE HID_ReportDescriptor[] = {
  HID_UsagePageVendor( 0x00                                   ),
  HID_Usage(           0x01                                   ),
  HID_Collection(      HID_Application                        ),
    HID_LogicalMin(    0                                      ),
    HID_LogicalMaxS(   0xFF                                   ),
    HID_ReportSize(    8                                      ),  // bits
    HID_ReportCount(   INREPORT_SIZE                          ),  // bytes
    HID_Usage(         0x01                                   ),
    HID_Input(         HID_Data | HID_Variable | HID_Absolute ),
    HID_ReportCount(   OUTREPORT_SIZE                         ),  // bytes
    HID_Usage(         0x01                                   ),
    HID_Output(        HID_Data | HID_Variable | HID_Absolute ),
  HID_EndCollection,
};

HID_ReportCount() macro supports upto 255 (single byte) as its parameter.
For more bytes (up to 0xFFFF), apply this HID_ReportCountS() macro (two bytes)

#define HID_ReportCountS(x)     0x96,(x&0xFF),((x>>8)&0xFF)

I don't know what is the reliable maximum report size on Windows, but I recommend you less than or equal to 4 Kbytes (page size of PCI bus).



Split the input report
The report is split by wMaxPacketSize (endpoint descriptor) of the endpoint. It's usually 64 bytes for full-speed HID device, but confirm your descriptor definition.

Above 191 bytes report is split into three transactions,

64, 64, 63

Above report descriptor defines no report ID. Then, this division is fine.
If you use any report ID for more input-report formats, the report is preceded by the report ID, the division becomes as follows.

(1byte report ID + 63), 64, 64

If any other input report longer than this one is defined, this report transfer should be terminated by ZLP (Zero-Length Packet), because the last transaction matches to wMaxPacketSize

(1byte report ID + 63), 64, 64, ZLP

The largest report don't need to terminate with ZLP, even when it ends up with wMaxPacketSize transaction.

Complicated? :-)



Endpoint handling
When the hardware finishes to collect whole data for the report, the firmware makes up the entire report on a buffer. The first transaction (64 bytes) is put to the endpoint buffer using USB_WriteEP(), in the data acquisition routine. See this post for the details.

"HID Mouse keeps sending unneeded data!"
http://www.keil.com/forum/docs/thread11531.asp

The second and later transactions are handled in the endpoint ISR, USB_EndPointN. This ISR is called when the endpoint buffer becomes empty by a successful transaction. Every time the USB_EndPointN is called, put the next transaction, if any, by USB_WriteEP().

You have to fiddle several flags and counter to make this work as expected.

Tsuneo

"C8051F340 USB_Bulk example question" on SiLabs Forum
www.cygnal.org/.../001627.html



"Report Descriptor"

HID_ReportID(0x11),      // Input Report 11

As the report descriptor has just single definition of input report, you can do without the report ID.
Of course, you can apply report ID as you wrote, too.
If you have plan to add more input reports, the report ID will ease the extension.



"Endpoint Descriptor"

0x40,0x24,                         /* wMaxPacketSize */

This is the problem. Set wMaxPacketSize to 64 (LSB first, as usual on USB).

0x40,0x00,                         /* wMaxPacketSize = 64 */

"USB_EndPoint1"

DWORD byte_count = 0;

Make byte_count to static, or global.
USB_EndPoint1() is called by the USB ISR every time a transaction finishes.
Anyway, I think this byte_count is not useful in your code, because you does it with report_block_number.

In this implementation, your device continuously puts the input report at the rate defined by the endpoint descriptor (bInterval). As it is 32 ms, the first transaction (64 bytes) and later one (32 bytes) are sent to the host alternately, in this rate. (The entire transfer takes 64 ms).

If you want to send the report just when the device detects a change on the target, rewrite it as described in above post.

Tsuneo

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

Instead of OUT report, Feature report is primarily handled by control transfer. If you want to exercise the control write transfer implementation, I'll guide you.

Tsuneo