1 Reply Latest reply on May 29, 2015 1:14 AM by Madhu Lakshmipathy

    Multiple USB UVC endpoints (multiple webcams)

    content.librarian

      I am trying to modify the See3CAM_CX3RDK_ e-CAM59CX3 example found here: http://www.cypress.com/cx3/ and add another usb streaming endpoint.  The mipi device that I have attached to is actually sending frames from multiple different cameras.  These frames have a header in the first line of the frame which allows me to tell which camera they came from.

         

       

         

      I have successfully modified the USB descriptor so that linux sees two separate UVC cameras (/dev/video0 and /dev/video1)  Originally the application uses this socket for video:

         

      dmaCfg.consSckId[0]         = CY_U3P_UIB_SOCKET_CONS_3;

         

      If I change this to CY_U3P_UIB_SOCKET_CONS_5 I am able to switch the video stream to /dev/video1.  I am not able to stream to both video enpoionts at once however.

         

      Reading in cyu3dma.h I can see that there is no CyU3PDmaMultiType_t that is many to many which is what I think I want.  The existing application uses CY_U3P_DMA_TYPE_MANUAL_MANY_TO_ONE.

         

      Is it possible to have the DMA switch endpoints during it's callback?  I would like to change the consSckId on the fly so that I can stream frames to either video endpoint at will.

         

      Does CyU3PUsbMapStream or CyU3PUsbChangeMapping help me accomplish this? I cannot find an example of either of these functions ANYWHERE on the web.  I've read the documentation but I don't understand exactly how I should use them.

         

       

         

      Attached is the unmodified example project.  The only changes I've made are duplicating the bytes in the esUVCUSBSSConfigDscr struct.  The rest of the application and dma setup I haven't touched.

         

       

         

      Thanks for any tips in advance.

         

      Regards,

         

      Ben