MIPI Cameras¶

The MitySOM-QC6490 Devkit supports image and video capture via the MIPI CSI interfaces ( Note that if you are using the 1.0 SDK, CSI0 is the only MIPI CSI interface supported).

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

Note that the connector on the Development Board is a Hirose FH12A-22S-0.5SH(55) (22 pin 0.5 mm pitch).

Also note that when installing the cable the dark brown latch on the connector should be up and the cable should be inserted between the dark brown latch and light brown body with the pins on the cable facing up. Once the cable is in position the dark brown latch should be pushed down to secure the cable.

Please see the picture below for an example of a properly connected cable:

Known Working Cameras¶

The Waveshare OV9281-120 Mono Camera was used to validate the MIPI CSI interface. Note that this module has a 15 pin 1.0 mm pitch interface and you will need to acquire a 15 pin 1.0 mm pitch to 22 pin 0.5 mm pitch adapter cable in order to use this module on the Development Board.

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.

Using Multiple Cameras¶

If using SDK version 1.1 or newer, up to 5 cameras can be connected to the Development Board. ( Note that if using the 1.1 SDK, only 3 of the cameras can be streamed from simultaneously).

1. Connect the desired number of cameras to the CSI ports sequentially, starting with CSI0. If for some reason it is required to use specific CSI ports, please reach out via the forums
2. Download the camera driver ipk corresponding to the number of cameras connected.
   1. For 1, 2, or 3 cameras, download 1_2_3_cams_chicdk-kt_1.0.qcom-r0.cl1_qcm6490.ipk.
   2. For 4 or 5 cameras, download 4_5_cams_chicdk-kt_1.0.qcom-r0.cl1_qcm6490.ipk
3. Move the ipk to the SOM with adb, scp, a USB flash drive, etc.
   To use adb, open a terminal on the host machine and navigate to the directory you downloaded the ipk to, then run the following command
   

   adb push {name of ipk file} /root/
   

4. Install the ipk using opkg and restart the camera server with the following commands:
   

   mount -o remount,rw /usr
   opkg --nodeps install /home/root/{name of ipk file} --force-reinstall
   systemctl restart cam-server
   

5. To use individual cameras, follow the same instructions as above but set the camera= property in the command accordingly.
   For example: To use the camera connected to CSI2, change the command to qtiqmmfsrc name=camsrc camera=2
6. To stream multiple cameras simultaneously, you can launch individual gstreamer pipelines in their own processes. You can also utilize the qtivcomposer plugin.
   For example: To stream CSI0, CSI1, and CSI2 to a connected display simultaneously, use the following command and gstreamer pipeline:
   

   # First export the display with the following command:
   export XDG_RUNTIME_DIR=/dev/socket/weston && export WAYLAND_DISPLAY=wayland-1
   
   gst-launch-1.0 -e qtivcomposer name=mixer sink_0::position="<0, 0>" sink_0::dimensions="<640, 360>" sink_1::position="<640, 0>" \
   sink_1::dimensions="<640, 360>" sink_2::position="<0, 360>" sink_2::dimensions="<640, 360>" sink_3::position="<640, 360>" \
   sink_3::dimensions="<640, 360>" mixer.src ! queue ! waylandsink enable-last-sample=false fullscreen=true sync=false async=true \
   qtiqmmfsrc name=camsrc_0 camera=0 ! queue ! video/x-raw, format=NV12, width=640, height=360, framerate=30/1 ! queue ! mixer.sink_0 \
   qtiqmmfsrc name=camsrc_1 camera=1 ! queue ! video/x-raw, format=NV12, width=640, height=360, framerate=30/1 ! queue ! mixer.sink_1 \
   qtiqmmfsrc name=camsrc_2 camera=2 ! queue ! video/x-raw, format=NV12, width=640, height=360, framerate=30/1 ! queue ! mixer.sink_2
   

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