1 Reply Latest reply on Jun 3, 2019 12:00 AM by KandlaguntaR_36

    CX3 support 4K@30fps?




      We want to development 4K@30fps camera and survey CX3/FX3 now. But some points let me confuse.


      1. We have contact three CMOS module maker (SONY/Socionext/Thine) to discuss using CX3  structure. They think the CX3 throughput only 1.6G~2Gbps. But we have test FX3, then it can meet it.

      2. The CX3 can provide 4K@30fps? or FX3?

      3. CX3/FX3 can support YUY2 format?

        • 1. Re: CX3 support 4K@30fps?



          1. The maximum bandwidth supported by CX3 is 2.4 Gbps. It has four MIPI lane. Each MIPI lane can support upto 1 Gbps. So if you want to use all the 4 lanes, then CX3 can support only 600Mbps/lane. On the other hand, if you are only using 2 lanes, then each lane can support up to 1Gbps.


          You should make sure that the throughput does not exceed 2.4 Gbps. The throughput can be determined by the formula given below.


          Image throughput = bits per pixel × (Horizontal resolution + Horizontal blanking) × (Vertical resolution + vertical blanking) × frames per second


          For example, some of the resolution, frame rate, and color formats supported by CX3 are given below:



          • 1920 × 1080 (FHD) , 30fps,60fps in YUV422 format
          • 1280 × 720p (HD), 60fps, 120fps in YUV422 format
          • 3840 × 2160 (uHD, 4k x 2k), 16fps in YUV422 format, 30fps in JPEG format with MJPEG 6:1 compression
          • 4096 × 2160 (4k native), 30fps in RAW8 format
          • 13MP , 10fps YUV422 format
          • 8MP, 16 fps YUV422 format



          2. CX3 acts as MIPI to USB Superspeed device controller and FX3 acts as 32-bit parallel interface to USB Superspeed device controller.

               The maximum bandwidth supported by parallel interface of FX3 is 32-bit @ 100 MHz. Hence, it can support upto 3.2 Gbps.


          The maximum bandwidth that CX3 can support is limited by the GPIF II block of CX3. GPIF II is a parallel interface of CX3 which is connected to MIPI CSI-2 to Parallel block. In CX3 chip, the GPIF II supports upto 24-bit @ 100 MHz.


               MIPI -> Parallel --> GPIF II --> SS USB


            If we ignore the blanking time for time being, the image throughput would be 3840*2160*16(bits)*30(fps) = 3.98 Gbps. This is neither supported by CX3 nor FX3.  


          CX3 can supports 4K YUY2 at 16 fps and FX3 can support upto 22 fps.


          3. CX3/FX3 can support YUY2 format?

             Yes, it supports YUY2.


          Refer CX3 Firmware: Frequently Asked Questions - KBA91297  and CX3 Hardware: Frequently Asked Questions - KBA91295  for more details.