MIPI Cameras¶

The MitySOM-QC6490 Devkit supports image and video capture via the MIPI CSI interfaces ( Note that currently CSI0 is the only MIPI CSI interface supported. Support for CSI1-CSI4 will be added in a future software release).

Development Board Configuration¶

Ensure that Switch S8 is set properly.

• Switch 1 should be set to enable MIPI, which is a top level enable for 1.8 V for the MIPI interface
• Switch 2 can be either set or not set
  • If Switch 2 is not set the 1.8V comes from the DC supply on the Development Kit
  • If Switch 2 is set the 1.8V comes from the SOM
• Switch 3 should NOT be set for Rev 1 or 2 of the Development Board as 3.3V from the SOM may actually be a higher volage. See MitySOM-QC6490 Development Kit Datasheet for further details
• Switch 4 should be set to enable the 3V3 CSI from the DC supply

Known Working Cameras¶

Note that Waveshare OV9281-120 Mono Camera was used to validate the MIPI CSI interface.

Capturing Single Images¶

1. Ensure the qcom-multimedia-image has been flashed onto the MitySOM-QC6490.
   1. You can verify which image you are working with via the following command:
      

      root@qcs6490-mitysom-devkit:~# cat /etc/buildinfo | grep IMAGE_BASENAME
      IMAGE_BASENAME = qcom-multimedia-image 
      

2. The following Gstreamer pipeline will allow you to capture a single JPEG image:
   

   gst-launch-1.0 qtiqmmfsrc camera=0 exposure-mode=0 manual-exposure-time=1333333 ! jpegenc snapshot=true ! identity error-after=2 ! filesink location=snap.jpg
   

   1. Note that this pipeline uses manual exposure. The value after manual-exposure-time= is the exposure time in nanoseconds.
   2. Further details on the qtiqmmfsrc Qualcomm GStreamer plugin and what properties are supported can be found here

Capturing Video¶

1. Ensure the qcom-multimedia-image has been flashed onto the MitySOM-QC6490.
   1. You can verify which image you are working with via the following command:
      

      root@qcs6490-mitysom-devkit:~# cat /etc/buildinfo | grep IMAGE_BASENAME
      IMAGE_BASENAME = qcom-multimedia-image 
      

2. The following Gstreamer pipeline will allow you to capture an MP4 encoded video:
   

   gst-launch-1.0 -e qtiqmmfsrc name=camsrc camera=0 ! \
   video/x-raw,format=NV12,width=1280,height=720,framerate=30/1,\
   interlace-mode=progressive,colorimetry=bt601 ! v4l2h264enc \
   capture-io-mode=4 output-io-mode=5 extra-controls="controls,video_bitrate=6000000,\
   video_bitrate_mode=0;" ! h264parse ! mp4mux ! filesink location=mux_avc.mp4
   

   1. Once the video capture begins a timer will be displayed. Use Ctrl+C to end video capture.
   2. Upon ending capture an MP4 video named mux_avc.mp4 can be found in your current working directory.

Troubleshooting¶

• Double check the camera module connection to the FPC connector at CSI0.
• Restart the camera server with the following command:
  

  systemctl restart cam-server
  

• After restarting the cam-server, or rebooting, search the kernel log for a successful probe of the camera module by running the following command:
  

  journalctl | grep -i "probe suc" 
  

  • If the sensor is properly connected and its I2C management interface is operational, the camera driver will successfully probe the camera module resulting in the following output:
    

    qcs6490-mitysom-devkit kernel: CAM_INFO: CAM-SENSOR: cam_sensor_driver_cmd: 939: Probe success,slot:1,slave_addr:0xc0,sensor_id:0x9281, is always on: 0