Code:

#define USB_BUFFER_SIZE 8
PROGMEM char usbHidReportDescriptor[29] = {
    0x06, 0xA0, 0xFF,   // USAGE_PAGE (Vendor Defined page 0xA1)
    0x09, 0x01,         // USAGE (Vendor Usage 0x01)
    0xA1, 0x01,         // COLLECTION (Application)
                        // Global items
    0x15, 0x00,         //   LOGICAL_MINIMUM(0)
    0x26, 0xFF, 0x00,   //   LOGICAL_MAXIMUM(255)
    0x75, 0x08,         //   REPORT_SIZE (8 Bits)
    0x95, USB_BUFFER_SIZE,    //   REPORT_COUNT (8  8 Bits, 8 Bytes)
                        // INPUT
    0x09, 0x03,         //   USAGE (Vendor Usage 0x03)
    0x81, 0x02,         //   INPUT (Data,Variable,Abs)
                        // OUTPUT
    0x09, 0x04,         //   USAGE (Vendor Usage 0x04)
    0x91, 0x02,         //   OUTPUT(Data, Variable,Abs
                        // Feature
    0x09, 0x05,         //   USAGE (Vendor Usage 0x05)
    0xB1, 0x02,         //   Feature (Data, Variable,Abs)
    0xC0                // END_COLLECTION
};

Code:

static uchar rest, curpos, currep;
usbMsgLen_t usbFunctionSetup(uchar data[8]) {
usbRequest_t    *rq = (void *)data;
    // HID-Class Request
    if ((rq->bmRequestType & USBRQ_TYPE_MASK) == USBRQ_TYPE_CLASS) {  
   if(rq->bRequest == USBRQ_HID_SET_REPORT) {

    // Receiving more thana single byte needs usbFunctionWrite() 
      curpos = 0;                
        rest = rq->wLength.word;  
        // Limit size
        if(rest > sizeof(usbrec)) rest = sizeof(usbrec);
        // flag usage of usbFunctionWrite() 
      return USB_NO_MSG;                   
      }
   }
    return 0;
}

uchar usbFunctionWrite(uchar *data, uchar len)
{
   uchar i;
    if(len > rest) len = rest;               
    rest -= len;
    for(i = 0; i < len; i++)
        usbrec[curpos++] = data[i];
    if (rest == 0) {
   
       // Process results
       
       // Write the buffer to my lcd display
        write(0,0,0,usbrec);
        
     return 1;
   }  
   else
      return 0;  
}

Code:

usbSetInterrupt(usbcmd, sizeof(usbcmd));  // usbcmd is char[8]

Code:

...
  private
    { Private-Deklarationen }
    dev: TJvHidDevice;
...
const
    USB_BUFFER_SIZE = 8;
...
type
  TLCD = packed record
    ID: byte;
    text: array[0..USB_BUFFER_SIZE-1] of char;
  end;
...
procedure TForm1.log(s: string);
begin
  ListBox1.ItemIndex := ListBox1.Items.Add(s);
end;
...
procedure TForm1.HIDCtlDeviceChange(Sender: TObject);
var
  x: integer;
  s: string;
begin
  with hidCtl do begin
    // check if owned device was plugged out
    if Assigned(Dev) and not Dev.IsPluggedIn then begin
      // give back device
      s := dev.ProductName;
      CheckIn(Dev);
      log(s + ' disconnected');
      dev := nil;
    end;
    // no device connected
    if not Assigned(Dev) then
      // take over device
      if CheckOutByID(Dev, $16C0, $05DF) then begin
        log(dev.ProductName + ' connected');
      end;
  end;
end;
...
procedure TForm1.Button1Click(Sender: TObject);
var
 rep:TLCD;

begin
  if assigned(dev) then begin
    rep.id:=0;
    strpcopy(rep.text,'Hallo');
    dev.setOutputReport(rep,sizeOf(rep));
  end;
end;
...
procedure TForm1.HIDCtlDeviceData(HidDev: TJvHidDevice; ReportID: Byte;
  const Data: Pointer; Size: Word);
var
  buffer: array[0..100] of char;
  I: integer;
  s:string;
begin
     Move(Data^, buffer[0], Size);
     s:='';
     for i:=0 to size-1 do s:=s+', '+intToStr(ord(buffer[i]));
     log(s); 
end;