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NXP FRDM i.MX 93 Board Camera Usage Guide

🚀 Introduction​

This article guides you on how to get started using TechNexion camera modules on the NXP FRDM i.MX 93 board.

📸 Supported Camera Modules​

Camera SeriesProducts
TEVS
TEVS-AR0144
TEVS-AR0145
TEVS-AR0234
TEVS-AR0235
TEVS-AR0246
TEVS-AR0521
TEVS-AR0522
TEVS-AR0544
TEVS-AR0821
TEVS-AR0822
TEVS-AR0830
TEVS-AR1335
TEVS-AR2020
Camera Sensor Comparison

🔧 Hardware Setup Instructions​

Connect the Adapter Board and Camera Cable​

To set up the TechNexion camera, connect the adapter board and camera cable to the FPC 22-Pin connector on the board as shown in the image below.

warning

The RPI 22-pin connector on the adapter board has two directions. Please make sure the pin definition matches the adapter board.

🧰 Camera Installation Instructions​

We provide two methods to install camera drivers and device tree blobs. Depending on your needs, you can choose the most suitable method. If you are new to this, we recommend starting with Method 1. If you have a custom Linux kernel and device tree, you can try Method 2.

Method 1 - Using TechNexion Pre-built image​

Prepare Yocto demo image for testing TechNexion camera​

To test TechNexion TEVS Series cameras, you need a demo image that includes the required Device Tree Blobs (DTBs) and camera drivers. Pre-built demo images are available for download from TechNexion's server.

🔗 Download Prebuilt Image for IMX93-FRDM

Flashing the Image​

You can flash the image to an SD Card using the following methods:

Boot Mode

Make sure your board is set to boot from SD card or eMMC.
Refer to the official NXP guide 🔗 Getting Started with the FRDM-IMX93

Use balenaEtcher to write the image to your SD card:

🔗

Method 2 - Build custom Linux kernel with camera driver​

  1. Download the camera driver and device tree blobs.

    $ git clone https://github.com/TechNexion-Vision/nxp_evk_camera.git -b tn-imx_6.18.20_2.0.0-stable

  2. Copy files to your kernel source code.

    $ cd nxp_evk_camera/

    ~/nxp_evk_camera$ cp arch/arm64/boot/dts/freescale/imx93-11x11-frdm-tevs-rpi22.dtso <fetch_kernel_folder>/arch/arm64/boot/dts/freescale/

  3. Modify the Makefile to add the driver.

    $ cd <fetch_kernel_folder>/drivers/media/i2c/
    ~/<fetch_kernel_folder>/drivers/media/i2c/$ vi Makefile

    Add this line to the Makefile.

    obj-$(CONFIG_VIDEO_TEVS) += tevs/

  4. Modify Kconfig to add camera configuration.

    ~/<fetch_kernel_folder>/drivers/media/i2c/$ vi Kconfig

    Add this part under "Camera sensor devices" menu in Kconfig.

    config VIDEO_TEVS
      tristate "TechNexion TEVS sensor support"
      depends on OF
      depends on GPIOLIB
      select REGMAP_I2C
      select V4L2_CCI_I2C
      default m
      help
        This is a Video4Linux2 sensor driver for the TechNexion
        TEVS camera sensor with a MIPI CSI-2 interface.

  5. Modify the Makefile to add the device tree.

    $ cd <fetch_kernel_folder>/arch/arm64/boot/dts/freescale/
    ~/<fetch_kernel_folder>/arch/arm64/boot/dts/freescale/$ vi Makefile

    Add these lines to the Makefile.

    imx93-11x11-frdm-tevs-rpi22-dtbs := imx93-11x11-frdm.dtb imx93-11x11-frdm-tevs-rpi22.dtbo
    dtb-$(CONFIG_ARCH_MXC) += imx93-11x11-frdm-tevs-rpi22.dtb

  6. Compile the kernel and module driver.

    Finally, you can start compiling your new Image files, then copy and replace the Image files on the SD card.

📸 Camera Testing Instructions​

Specify Camera DTBO in U-Boot​

  1. Connect the debug console cable to the baseboard (via USB-C).

  2. Power on the board and interrupt the boot process. Keep pressing Enter when the following message appears: Hit any key to stop autoboot:

  3. Specify the appropriate device tree for your camera using the fdtfile environment variable in U-Boot:

u-boot=> setenv fdtfile imx93-11x11-frdm-tevs-rpi22.dtb
  1. Save and continue the boot process:
u-boot=> saveenv
u-boot=> boot

🎛️ Setup the media controller before camera streaming​

To verify that the camera has been properly connected and linked, use the media-ctl command:

$ media-ctl -p

This will display media controller information, such as:


Media controller API version 6.18.20

Media device information
------------------------
driver          mxc-isi
model           FSL Capture Media Device
serial
bus info        platform:4ae40000.isi
hw revision     0x0
driver version  6.18.20

Device topology
- entity 1: crossbar (3 pads, 3 links, 1 route)
            type V4L2 subdev subtype Unknown flags 0
            device node name /dev/v4l-subdev0
        routes:
                0/0 -> 2/0 [ACTIVE]
        pad0: SINK,MUST_CONNECT
                [stream:0 fmt:UYVY8_1X16/640x480 field:none colorspace:srgb xfer:srgb ycbcr:601]
                <- "csidev-4ae00000.csi":1 [ENABLED,IMMUTABLE]
        pad1: SINK,MUST_CONNECT
                <- "mxc_isi.output":0 [ENABLED,IMMUTABLE]
        pad2: SOURCE
                [stream:0 fmt:UYVY8_1X16/640x480 field:none colorspace:srgb xfer:srgb ycbcr:601]
                -> "mxc_isi.0":0 [ENABLED,IMMUTABLE]

- entity 5: mxc_isi.0 (2 pads, 2 links, 0 routes)
            type V4L2 subdev subtype Unknown flags 0
            device node name /dev/v4l-subdev1
        pad0: SINK
                [stream:0 fmt:UYVY8_1X16/640x480 field:none colorspace:srgb xfer:srgb ycbcr:601
                 compose.bounds:(0,0)/640x480
                 compose:(0,0)/640x480]
                <- "crossbar":2 [ENABLED,IMMUTABLE]
        pad1: SOURCE
                [stream:0 fmt:YUV8_1X24/640x480 field:none colorspace:jpeg xfer:srgb ycbcr:601 quantization:full-range
                 crop.bounds:(0,0)/640x480
                 crop:(0,0)/640x480]
                -> "mxc_isi.0.capture":0 [ENABLED,IMMUTABLE]

- entity 8: mxc_isi.0.capture (1 pad, 1 link)
            type Node subtype V4L flags 0
            device node name /dev/video0
        pad0: SINK
                <- "mxc_isi.0":1 [ENABLED,IMMUTABLE]

- entity 16: mxc_isi.output (1 pad, 1 link)
             type Node subtype V4L flags 0
        pad0: SOURCE
                -> "crossbar":1 [ENABLED,IMMUTABLE]

- entity 23: csidev-4ae00000.csi (2 pads, 2 links, 1 route)
             type V4L2 subdev subtype Unknown flags 0
             device node name /dev/v4l-subdev2
        routes:
                0/0 -> 1/0 [ACTIVE]
        pad0: SINK
                [stream:0 fmt:UYVY8_1X16/640x480 field:none colorspace:srgb xfer:srgb ycbcr:601 quantization:full-range]
                <- "tevs 2-0048":0 [ENABLED]
        pad1: SOURCE
                [stream:0 fmt:UYVY8_1X16/640x480 field:none colorspace:srgb xfer:srgb ycbcr:601 quantization:full-range]
                -> "crossbar":0 [ENABLED,IMMUTABLE]

- entity 28: tevs 2-0048 (1 pad, 1 link, 0 routes)
             type V4L2 subdev subtype Sensor flags 0
             device node name /dev/v4l-subdev3
        pad0: SOURCE
                [stream:0 fmt:UYVY8_1X16/640x480@1/60 field:none colorspace:srgb xfer:srgb ycbcr:601 quantization:full-range
                 crop.bounds:(0,0)/1280x800
                 crop:(0,0)/640x480]
                -> "csidev-4ae00000.csi":0 [ENABLED]

Showing the output as an image can make it easier to understand.

note

If you want to see the graph, you can use the --print-dot option.

$ media-ctl --print-dot > graph.dot
$ dot -Tpng graph.dot > graph.png
# If you don't have the tool, you need to install it as follows.
# sudo apt-get install -y graphviz.

Set the resolution and format of all media entities to match the camera's output. This means all components in the media pipeline must align with the camera's output settings.

Use the v4l2-ctl command to check the camera's supported formats, resolutions, and frame intervals.

# formats
$ v4l2-ctl -d /dev/v4l-subdev3 --list-subdev-mbus-codes
  ioctl: VIDIOC_SUBDEV_ENUM_MBUS_CODE (pad=0,stream=0)
          0x200f: MEDIA_BUS_FMT_UYVY8_1X16

# resolutions
$ v4l2-ctl -d /dev/v4l-subdev3 --list-subdev-framesize code=0x200f
  ioctl: VIDIOC_SUBDEV_ENUM_FRAME_SIZE (pad=0,stream=0)
          Size Range: 640x480 - 640x480
          Size Range: 1280x720 - 1280x720
          Size Range: 1280x800 - 1280x800

# frame interval of resolution
$ v4l2-ctl -d /dev/v4l-subdev3 --list-subdev-frameintervals width=640,height=480,code=0x200f
  ioctl: VIDIOC_SUBDEV_ENUM_FRAME_INTERVAL (pad=0,stream=0)
          Interval: 0.017s (60.000 fps)
          Interval: 0.033s (30.000 fps)
          Interval: 0.050s (20.000 fps)
          Interval: 0.067s (15.000 fps)
          Interval: 0.100s (10.000 fps)
          Interval: 0.200s (5.000 fps)

$ v4l2-ctl -d /dev/v4l-subdev3 --list-subdev-frameintervals width=1280,height=720,code=0x200f
  ioctl: VIDIOC_SUBDEV_ENUM_FRAME_INTERVAL (pad=0,stream=0)
          Interval: 0.017s (60.000 fps)
          Interval: 0.033s (30.000 fps)
          Interval: 0.050s (20.000 fps)
          Interval: 0.067s (15.000 fps)
          Interval: 0.100s (10.000 fps)
          Interval: 0.200s (5.000 fps)

$ v4l2-ctl -d /dev/v4l-subdev3 --list-subdev-frameintervals width=1280,height=800,code=0x200f
  ioctl: VIDIOC_SUBDEV_ENUM_FRAME_INTERVAL (pad=0,stream=0)
          Interval: 0.017s (60.000 fps)
          Interval: 0.033s (30.000 fps)
          Interval: 0.050s (20.000 fps)
          Interval: 0.067s (15.000 fps)
          Interval: 0.100s (10.000 fps)
          Interval: 0.200s (5.000 fps)

🎥 Start Camera Video Stream via GStreamer​

🎬 Launch GStreamer Pipeline​

Bring up the camera (/dev/video0) with 1280x720 at 30 FPS by Gstreamer pipeline :

$ media-ctl -V "'crossbar':0 [fmt:UYVY8_1X16/1280x720 field:none colorspace:srgb xfer:srgb ycbcr:601]"
$ media-ctl -V "'mxc_isi.0':0 [fmt:UYVY8_1X16/1280x720 field:none colorspace:srgb xfer:srgb ycbcr:601]"
$ media-ctl -V "'csidev-4ae00000.csi':0 [fmt:UYVY8_1X16/1280x720 field:none colorspace:srgb xfer:srgb ycbcr:601]"
$ media-ctl -V "'tevs 2-0048':0 [fmt:UYVY8_1X16/1280x720@1/30 field:none colorspace:srgb xfer:srgb ycbcr:601]"
$ gst-launch-1.0 v4l2src device=/dev/video0 ! "video/x-raw, format=YUY2, width=1280, height=720" ! fpsdisplaysink video-sink=waylandsink sync=false -v

Bring up the camera (/dev/video0) with 640x480 at 60 FPS by Gstreamer pipeline :

$ media-ctl -V "'crossbar':0 [fmt:UYVY8_1X16/640x480 field:none colorspace:srgb xfer:srgb ycbcr:601]"
$ media-ctl -V "'mxc_isi.0':0 [fmt:UYVY8_1X16/640x480 field:none colorspace:srgb xfer:srgb ycbcr:601]"
$ media-ctl -V "'csidev-4ae00000.csi':0 [fmt:UYVY8_1X16/640x480 field:none colorspace:srgb xfer:srgb ycbcr:601]"
$ media-ctl -V "'tevs 2-0048':0 [fmt:UYVY8_1X16/640x480@1/60 field:none colorspace:srgb xfer:srgb ycbcr:601]"
$ gst-launch-1.0 v4l2src device=/dev/video0 ! "video/x-raw, format=YUY2, width=640, height=480" ! fpsdisplaysink video-sink=waylandsink sync=false -v

🚨 Troubleshooting​

Verify Camera Initialization​

Use dmesg to check if the TEVS camera module was initialized correctly.

  $ dmesg -t | grep tevs
    tevs 2-0048: tevs_probe() device node: tevs@48
    tevs 2-0048: Version:26.3.0.1
    tevs 2-0048: Product:TEVS-AR0144, HeaderVer:3, MIPI_Rate:800
    tevs 2-0048: Chip ID: 0x0356
    tevs 2-0048: probe success

Confirm Board and Camera DTB​

Check if the correct DTB is loaded with a matching camera model.

  $ dmesg -t | grep -i model
    Machine model: NXP FRDM-IMX93

Check Available Video Devices​

Verify that the video devices are available.

  $ v4l2-ctl --list-devices

Example output:

mxc-isi-cap (platform:4ae40000.isi):
    /dev/video0
    /dev/video1
    /dev/media0