FX3 Add Vendor Interface

Cypress Community has official document Vendor Interface in UVC.

Summary as the following

USB Descriptor Update

1. Update Length of Descriptor

   Update the length of the descriptor and all sub-descriptor fields from D9 to E2 (in CyFxUSBSSConfigDscr) and CD to D6 (in CyFxUSBHSConfigDscr).

2. Increment of the interface

   Change the number of interfaces from 2 to 3.

3. Add Interface Descriptor For Vendor Command

   After the Endpoint Descriptor for BULK Streaming Video Data (in CyFxUSBHSConfigDscr) and Super Speed Endpoint Companion Descriptor for BULK endpoint (in CyFxUSBSSConfigDscr), include the following:

     0x09,                           /* Descriptor size */
     CY_U3P_USB_INTRFC_DESCR,        /* Interface descriptor type */
     0x02,                           /* Interface number */
     0x00,                         /* Alternate setting number */
     0x00,                           /* Number of end points */
     0xFF,                           /* Interface class */
     0x00,                           /* Interface sub class */
     0x00,                           /* Interface protocol code */
     0x00                            /* Interface descriptor string index */

Setup Callback Function

In the CyFxUVCApplnUSBSetupCB() function of the uvc.c file, before the switch case for UVC Class Requests include the following template to handle vendor requests:

     if ((bmReqType & CY_U3P_USB_TYPE_MASK) == CY_U3P_USB_VENDOR_RQT)
        {
           switch(bRequest)
           {
                 case 0x76:
                     CyU3PDebugPrint(2, "Vendor command received…\n");
                                  /* Implement the code as per the functionality required*/
                        CyU3PUsbAckSetup();
                     return CyTrue;
                 default:
                     return CyFalse;
           }
       }