Code:

#define USB_CFG_HAVE_INTRIN_ENDPOINT    1
/* Define this to 1 if you want to compile a version with two endpoints: The
 * default control endpoint 0 and an interrupt-in endpoint (any other endpoint
 * number).
 */
#define USB_CFG_HAVE_INTRIN_ENDPOINT3   1
/* Define this to 1 if you want to compile a version with three endpoints: The
 * default control endpoint 0, an interrupt-in endpoint 3 (or the number
 * configured below) and a catch-all default interrupt-in endpoint as above.
 * You must also define USB_CFG_HAVE_INTRIN_ENDPOINT to 1 for this feature.
 */
#define USB_CFG_EP3_NUMBER              3
/* If the so-called endpoint 3 is used, it can now be configured to any other
 * endpoint number (except 0) with this macro. Default if undefined is 3.
 */

Code:

                       case 1:
                if(usbInterruptIsReady())
                  usbSetInterrupt(KbdBuffer, sizeof(KbdBuffer));
            break;

            case 2:
                if(usbInterruptIsReady3())
                  usbSetInterrupt3(MouseBuffer, sizeof(MouseBuffer));
            break;