7 Replies Latest reply on Dec 6, 2018 4:26 AM by aani

    UVC AN75779 blank screen

    343430142_3869541

      Hi, everyone

           I am using the FX3 to stream video from a image sensor which is controlled by ISP.

           The way of ISP control camera,it can showed video in moniter.

           By using FX3 EVK CYUSB3KIT-003,the whole video screen is all blank in AMCAP and FX3 show as a camera device in th Device Management. The ISP output data format is 720p@30fps ,YUV 4:2:2. The ISP used GPIF II connected FX3,which used 8bit databus.

           Base on AN75775 demo code(http://www.cypress.com/documentation/application-notes/an75779-how-implement-image-sensor-interface-using-ez-usb-fx3-usb), I mark the function about i2c.

           When the screen is blank, the uart debug "UVC: Completed 59683 frames and 0 buffers" ,the value of  frames is increase , but the buffer count of CyU3PDmaMultiChannelGetBuffer in CyFxUvcApplnDmaCallback function sometime is 0 and sometime is 7652,and the return of CyU3PDmaMultiChannelGetBuffer sometime is 69(CY_U3P_ERROR_ALREADY_PARTITIONED ),what's the problem and how I can solve it?

           Something about the GPIF II ,FV is low valid,LV is high valid,so I seted the Polarity of FV  is "active low" which is deffernt with the AN75779,and the state machine is changed which red cycle below.

      .and then in

      state.JPG

        • 1. Re: UVC AN75779 blank screen
          aani

          Hello Mini Nano,

           

          -Did you make any modifications to the application note firmware An75779? If yes, please mention the same.

          -Please let me know, why you selected the polarity of FV is "active low"?

          -What are the Buffer size and vertical blanking period?

           

          Regards,

          Anil Srinivas.

          • 2. Re: UVC AN75779 blank screen
            343430142_3869541

            Hello Anil Srinivas,

                     The state machine make me boggled.

            If the polarity of FV is active low , FV represent high or low in the state machine?

            Or whether the polarity of FV,it always represent high in the state machine ?

             

             

             

             

             

            -What are the Buffer size and vertical blanking period?

             

                the dma size is 0x4000,I am not sure the period of vertical blanking .

             

             

             

             

            -Did you make any modifications to the application note firmware An75779? If yes, please mention the same.

             

             

                 modify about iic .CyFxUVCApplnI2CInit、SensorReset、SensorInit,    three functions has closed(not used),other doesn't modify

             

             

            -Original-

            • 3. Re: UVC AN75779 blank screen
              343430142_3869541

              aani

              1.jpg

              Use oscilloscope to check the IPS output signals,the yellow is VS signal,blue is HS signal.So the FV is active low,is that right?

               

              But the LV signal,I am not sure.I guess it is active high,its oscilloscope below

              2.jpg

               

              then my modify for State Machine is right or not?

              machine.JPG

              • 4. Re: UVC AN75779 blank screen
                343430142_3869541

                aani

                 

                GPIF project

                 

                use this GPIF project ,got a error code:

                Error in CyU3PDmaMultiChannelGetBuffer: code 69

                • 5. Re: UVC AN75779 blank screen
                  aani

                  Hello Mini Nano,

                   

                  --Error 69 (0x45) is the timeout error which means the API is not able to get a buffer with data within the timeout duration (2000 mS). ( i.e. There is no data availble in the buffer)

                  --Does this error occur the first time you call the API or does it happen somewhere in between after few successful transfers?

                  --Please make sure that there is empty bufffers in the DMA Channel and all the previously filled buffers have been consumed by the USB (Computer)

                   

                  Regards,

                  Anil Srinivas.

                  • 6. Re: UVC AN75779 blank screen
                    343430142_3869541

                    Hello Anil,

                          

                    --Does this error occur the first time you call the API or does it happen somewhere in between after few successful transfers?

                          I think this error happen somewhere in between after few successful transfers,the DebugPrint show it completed 16380 frames an X buffer,the X mostly is 0,small amount is 3 or 1,never more than 10.
                          Sorry, I make a mistake. It doesn't completed 16380 frames,i confusion it .

                     

                     

                    --Please make sure that there is empty bufffers in the DMA Channel and all the previously filled buffers have been consumed by the USB (Computer)

                       How to make sure that?

                     

                     

                     

                    Thanks

                    • 7. Re: UVC AN75779 blank screen
                      aani

                      Hello Mini Nano,

                       

                      I have seen CyU3PDmaMultiChannelGetBuffer some times return value is 7652 in your uart debug prints. this 7652 error could not be returned by the base RTOS or by the FX3 API itself. I think this error happen after 858 frames transfer. please let me know time duration of FV high.

                       

                      Regards,

                      Anil Srinivas.