IMX8MM TEVS Camera Usage Guide

🚀 Introduction

This guide shows you how to get started using TechNexion camera modules on **EDM-WB-IMX8M-MINI ** board. You must have the background knowledge to modify the kernel configuration, rebuild, and replace the kernel and the device tree source (DTS). This article is based on the 🔗 Yocto 5.2 (Scarthgap) 2025Q3 Release with Linux kernel version 6.12.20-2.0.0.

📸 Supported Camera Modules

TEVS Series
VLS3 Series

Camera Series	Products
TEVS	TEVS-AR0144 TEVS-AR0145 TEVS-AR0234 TEVS-AR0521 TEVS-AR0522 TEVS-AR0821 TEVS-AR0822 TEVS-AR1335

Camera Series	Products
VLS3	VLS3-AR0144 VLS3-AR0145 VLS3-AR0234 VLS3-AR0521 VLS3-AR0522 VLS3-AR0821 VLS3-AR0822 VLS3-AR1335

e.g.

This article uses the TEVS-AR0521 as an example.

🧩 Supported Boards

SoM	Board
EDM-G-IMX8M-MINI	WB-EDM-G-IMX8M-MINI
PICO-IMX8M-MINI	PICO-PI-IMX8M-MINI PICO-WIZARD-IMX8M-MINI

🔧 Hardware Setup Instructions

1. Power Supply Preparation

Use a DC 5V or 12V power cable to supply power to the board.
If you're using FPD-Link III SerDes, a 12V power adapter (minimum 3A) is required. Connect it via the barrel jack connector.

2. Debug Console Connection

Prepare a USB-to-UART cable if you're connecting to a PC.
Connect it to the CONSOLE1 connector.

3. Display Output Connection

Prepare a panel for output display.
Connect the panel to the LVDS1 connector on the board.

About display

The provided DTBs include configuration for 10.1-inch and 15.6-inch LVDS display panels, as well as 5-inch MIPI panel. This allows the system to output video, which is useful for verifying camera streaming on screen.

4. Camera Interface (CSI) Overview

The board features one MIPI-CSI-2 interface, referred to as CSI1.
This uses a 70-pin board-to-board connector manufactured by Hirose.

About camera

Although the board has two CSI interfaces, only CSI1 is enabled. The IMX8M-MINI only supports one MIPI-CSI-2 interface.

💻 Prepare Yocto demo image for testing TechNexion camera

To test TechNexion cameras, you will need a Yocto-based demo image that includes the necessary device tree blobs and camera drivers.

🔽 Downloading the Demo Image

We provide a pre-built demo image to simplify using TEVS cameras, available for download on TechNexion's official server.

Download Link:

🔗 Supported Release List for EDM-G-IMX8MM
🔗 Supported Release List for PICO-IMX8MM

💾 Flashing the Image

You can flash the image to either e.MMC or an SD Card using one of the following methods:

Mothod 1. Using `uuu` Tool (Universal Update Utility)

TechNexion provides a guide to flash the image using the uuu tool: 🔗 How to Flash with UUU

Boot Mode

Before flashing, ensure the board is set to Serial Download Mode in the boot configuration.

Mothod 2. Using `ums` Command in U-Boot (USB Mass Storage)

Alternatively, you can write the image directly to flash storage over USB-OTG using U-Boot’s ums command: 🔗 Using UMS in U-Boot

U-Boot Requirement

The board must be booted with a version of U-Boot that supports the ums command. Typically, this is done from the existing e.MMC.

Mothod 3. For Windows Users

Use balenaEtcher to write the image to your SD card: 🔗 Using Balena Etcher

🛠️ Build Yocto

TechNexion supports building a Yocto-based Linux image tailored for camera modules using the following kernel and branch. If you are using prebuilt demo image, you can skip this section. Please refer to 📸 Camera Testing Instructions section for camera testing steps.

📦 Supported Linux Kernel

Linux Kernel Version	Yocto Branch
6.12.20	`tn-imx_6.12.20_2.0.0-stable`

📁 Source and Build Instructions

🔗 Fetch Yocto Source
📖 Build Yocto for EDM-G-IMX8MM
📖 Build Yocto for PICO-IMX8MM

📸 Camera Testing Instructions

🌳 Specify Camera DTBO in U-Boot

Connect the debug console cable to carrier board.
Power on the board and interrupt the boot process. Keep pressing Enter when the following message appears: Hit any key to stop autoboot:
Specify the appropriate device tree for your camera using the fdtfile environment variable in U-Boot:

CIS1 connector

u-boot=> setenv dtoverlay tevs

Continue boot process.

u-boot=> saveenv
u-boot=> boot

tip

Remember to append the overlay for the display panel, if you want to see the camera output on screen.
e.g.

u-boot=> setenv dtoverlay=tevs sn65dsi84-vl10112880

🎛️ Setup the media controller before camera streaming

Starting from kernel 6.12, the CSI driver supports media-ctl for configuring the pipeline on the i.MX8M Mini platform. 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 6.12.20

Media device information
------------------------
driver          imx7-csi
model           imx-media
serial
bus info        platform:32e20000.csi
hw revision     0x0
driver version  6.12.20

Device topology
- entity 1: csi (2 pads, 2 links, 0 routes)
            type V4L2 subdev subtype Unknown flags 0
            device node name /dev/v4l-subdev0
        pad0: SINK
                [stream:0 fmt:UYVY8_2X8/640x480 field:none colorspace:srgb xfer:srgb ycbcr:601 quantization:lim-range]
                <- "csis-32e30000.mipi-csi":1 [ENABLED,IMMUTABLE]
        pad1: SOURCE
                [stream:0 fmt:UYVY8_2X8/640x480 field:none colorspace:srgb xfer:srgb ycbcr:601 quantization:lim-range]
                -> "csi capture":0 [ENABLED,IMMUTABLE]

- entity 4: csi capture (1 pad, 1 link)
            type Node subtype V4L flags 0
            device node name /dev/video2
        pad0: SINK
                <- "csi":1 [ENABLED,IMMUTABLE]

- entity 10: csis-32e30000.mipi-csi (2 pads, 2 links, 0 routes)
             type V4L2 subdev subtype Unknown flags 0
             device node name /dev/v4l-subdev1
        pad0: SINK,MUST_CONNECT
                [stream:0 fmt:UYVY8_1X16/640x480 field:none colorspace:smpte170m xfer:709 ycbcr:601 quantization:lim-range]
                <- "tevs 1-0048":0 [ENABLED]
        pad1: SOURCE,MUST_CONNECT
                [stream:0 fmt:UYVY8_1X16/640x480 field:none colorspace:smpte170m xfer:709 ycbcr:601 quantization:lim-range]
                -> "csi":0 [ENABLED,IMMUTABLE]

- entity 15: tevs 1-0048 (1 pad, 1 link, 0 routes)
             type V4L2 subdev subtype Sensor flags 0
             device node name /dev/v4l-subdev2
        pad0: SOURCE
                [stream:0 fmt:SGRBG12_1X12/2592x1944@1/24 field:none colorspace:raw xfer:none ycbcr:601 quantization:full-range
                 crop.bounds:(0,0)/2592x1944
                 crop:(0,0)/2592x1944]
                -> "csis-32e30000.mipi-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-subdev2 --list-subdev-mbus-codes
  ioctl: VIDIOC_SUBDEV_ENUM_MBUS_CODE (pad=0,stream=0)
          0x200f: MEDIA_BUS_FMT_UYVY8_1X16
          0x300a: MEDIA_BUS_FMT_SGRBG10_1X10
          0x3011: MEDIA_BUS_FMT_SGRBG12_1X12

# resolutions
$ v4l2-ctl -d /dev/v4l-subdev2 --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: 1280x960 - 1280x960
          Size Range: 1920x1080 - 1920x1080
          Size Range: 2560x1440 - 2560x1440
          Size Range: 2592x1944 - 2592x1944

# frame interval of resolution
$ v4l2-ctl -d /dev/v4l-subdev2 --list-subdev-frameintervals width=640,height=480,code=0x200f
  ioctl: VIDIOC_SUBDEV_ENUM_FRAME_INTERVAL (pad=0,stream=0)
          Interval: 0.008s (120.000 fps)

$ v4l2-ctl -d /dev/v4l-subdev2 --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)

$ v4l2-ctl -d /dev/v4l-subdev2 --list-subdev-frameintervals width=1280,height=960,code=0x200f
  ioctl: VIDIOC_SUBDEV_ENUM_FRAME_INTERVAL (pad=0,stream=0)
          Interval: 0.017s (60.000 fps)

$ v4l2-ctl -d /dev/v4l-subdev2 --list-subdev-frameintervals width=1920,height=1080,code=0x200f
  ioctl: VIDIOC_SUBDEV_ENUM_FRAME_INTERVAL (pad=0,stream=0)
          Interval: 0.017s (60.000 fps)

$ v4l2-ctl -d /dev/v4l-subdev2 --list-subdev-frameintervals width=2560,height=1440,code=0x200f
  ioctl: VIDIOC_SUBDEV_ENUM_FRAME_INTERVAL (pad=0,stream=0)
          Interval: 0.031s (32.000 fps)

$ v4l2-ctl -d /dev/v4l-subdev2 --list-subdev-frameintervals width=2592,height=1944,code=0x200f
  ioctl: VIDIOC_SUBDEV_ENUM_FRAME_INTERVAL (pad=0,stream=0)
          Interval: 0.042s (24.000 fps)

Set resolution to 1280×720 for example.

Command Line
Script

$ media-ctl -V "'csi':0 [fmt:UYVY8_1X16/1280x720 field:none colorspace:srgb xfer:srgb ycbcr:601]"
$ media-ctl -V "'tevs 1-0048':0 [fmt:UYVY8_1X16/1280x720 field:none colorspace:srgb xfer:srgb ycbcr:601]"

#!/bin/bash

# Define the format and resolution as a variable
mdev="/dev/media0"
mediactl="media-ctl -d $mdev"
cam="tevs 1-0048"
csi="csi"
code="UYVY8_1X16"
width="1280"
height="720"
format="fmt:${code}/${width}x${height} field:none"

# Function to run media-ctl commands with error handling
echo "Set media controller..."

$mediactl -V "\"$cam\":0 [$format]"
$mediactl -V "\"$csi\":0/0 [$format]"

🎥 Start Camera Video Stream via GStreamer

🎬 Launch GStreamer Pipeline

Specify the capture device you just get and start gstreamer to get video stream on screen.
Replace <res_w> and <res_h> with your selected resolution(1280x720) and screen dimensions:

$ gst-launch-1.0 v4l2src device=/dev/video0 ! \
  "video/x-raw, format=UYVY, width=<res_w>, height=<res_h>" ! \
  waylandsink sync=false

✅ Check Media Controller

We can use media-ctl -p to check the media controller again after setting the resolution and media link as shown below:

Media controller API version 6.12.20

Media device information
------------------------
driver          imx7-csi
model           imx-media
serial
bus info        platform:32e20000.csi
hw revision     0x0
driver version  6.12.20

Device topology
- entity 1: csi (2 pads, 2 links, 0 routes)
            type V4L2 subdev subtype Unknown flags 0
            device node name /dev/v4l-subdev0
        pad0: SINK
                [stream:0 fmt:UYVY8_1X16/1280x720 field:none colorspace:srgb xfer:srgb ycbcr:601 quantization:lim-range]
                <- "csis-32e30000.mipi-csi":1 [ENABLED,IMMUTABLE]
        pad1: SOURCE
                [stream:0 fmt:UYVY8_1X16/1280x720 field:none colorspace:srgb xfer:srgb ycbcr:601 quantization:lim-range]
                -> "csi capture":0 [ENABLED,IMMUTABLE]

- entity 4: csi capture (1 pad, 1 link)
            type Node subtype V4L flags 0
            device node name /dev/video2
        pad0: SINK
                <- "csi":1 [ENABLED,IMMUTABLE]

- entity 10: csis-32e30000.mipi-csi (2 pads, 2 links, 0 routes)
             type V4L2 subdev subtype Unknown flags 0
             device node name /dev/v4l-subdev1
        pad0: SINK,MUST_CONNECT
                [stream:0 fmt:UYVY8_1X16/1280x720 field:none colorspace:srgb xfer:srgb ycbcr:601 quantization:full-range]
                <- "tevs 1-0048":0 [ENABLED]
        pad1: SOURCE,MUST_CONNECT
                [stream:0 fmt:UYVY8_1X16/1280x720 field:none colorspace:srgb xfer:srgb ycbcr:601 quantization:full-range]
                -> "csi":0 [ENABLED,IMMUTABLE]

- entity 15: tevs 1-0048 (1 pad, 1 link, 0 routes)
             type V4L2 subdev subtype Sensor flags 0
             device node name /dev/v4l-subdev2
        pad0: SOURCE
                [stream:0 fmt:UYVY8_1X16/1280x720@1/60 field:none colorspace:srgb xfer:srgb ycbcr:601 quantization:full-range
                 crop.bounds:(0,0)/1280x720
                 crop:(0,0)/1280x720]
                -> "csis-32e30000.mipi-csi":0 [ENABLED]

🚨 Troubleshooting

Check DTB Overlay in U-Boot

Make sure the correct Device Tree Blob (DTB) is specified in U-Boot.

CSI1 connector

  u-boot=> printenv dtoverlay
  dtoverlay=tevs vxt-vl050-070-8048nt

tip

The vxt-vl050-070-8048nt is an overlay for 5-inch LCD display panel.

Verify Camera Initialization

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

  $ dmesg -t | grep tevs
    /soc@0/bus@30800000/i2c@30a30000/tevs_mipi@48: Fixed dependency cycle(s) with /soc@0/bus@32c00000/mipi-csi@32e30000
    /soc@0/bus@32c00000/mipi-csi@32e30000: Fixed dependency cycle(s) with /soc@0/bus@30800000/i2c@30a30000/tevs_mipi@48
    /soc@0/bus@30800000/i2c@30a30000/tevs_mipi@48: Fixed dependency cycle(s) with /soc@0/bus@32c00000/mipi-csi@32e30000
    /soc@0/bus@30800000/i2c@30a30000/tevs_mipi@48: Fixed dependency cycle(s) with /soc@0/bus@32c00000/mipi-csi@32e30000
    /soc@0/bus@32c00000/mipi-csi@32e30000: Fixed dependency cycle(s) with /soc@0/bus@30800000/i2c@30a30000/tevs_mipi@48
    /soc@0/bus@30800000/i2c@30a30000/tevs_mipi@48: Fixed dependency cycle(s) with /soc@0/bus@32c00000/mipi-csi@32e30000
    /soc@0/bus@32c00000/mipi-csi@32e30000: Fixed dependency cycle(s) with /soc@0/bus@30800000/i2c@30a30000/tevs_mipi@48
    /soc@0/bus@32c00000/mipi-csi@32e30000: Fixed dependency cycle(s) with /soc@0/bus@30800000/i2c@30a30000/tevs_mipi@48
    /soc@0/bus@30800000/i2c@30a30000/tevs_mipi@48: Fixed dependency cycle(s) with /soc@0/bus@32c00000/mipi-csi@32e30000
    tevs 1-0048: tevs_probe() device node: tevs_mipi@48
    tevs 1-0048: Version:25.3.0.2
    tevs 1-0048: Product:TEVS-AR0521, HeaderVer:3, MIPI_Rate:800
    tevs 1-0048: Chip ID: 0x0000
    tevs 1-0048: 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: TechNexion EDM-G-IMX8MM and WB baseboard
    exc3000 2-002a: Retry 1 get EETI EXC3000 model: -6
    exc3000 2-002a: Retry 2 get EETI EXC3000 model: -6
    exc3000 2-002a: Retry 3 get EETI EXC3000 model: -6

Check Available Video Devices

Verify that the video devices are available.

  $ v4l2-ctl --list-device

Example output:

imx-capture (platform:32e20000.csi):
        /dev/video2
        /dev/media0

vsi_v4l2dec (platform:vsi_v4l2dec):
        /dev/video1

vsi_v4l2enc (platform:vsi_v4l2enc):
        /dev/video0

Typically, /dev/video2 is your primary camera capture device when using CSI1.

🚀 Introduction​

📸 Supported Camera Modules​

🧩 Supported Boards​

🔧 Hardware Setup Instructions​

1. Power Supply Preparation​

2. Debug Console Connection​

3. Display Output Connection​

4. Camera Interface (CSI) Overview​

💻 Prepare Yocto demo image for testing TechNexion camera​

🔽 Downloading the Demo Image​

Download Link:​

💾 Flashing the Image​

Mothod 1. Using uuu Tool (Universal Update Utility)​

Mothod 2. Using ums Command in U-Boot (USB Mass Storage)​

Mothod 3. For Windows Users​

🛠️ Build Yocto​

📦 Supported Linux Kernel​

📁 Source and Build Instructions​

📸 Camera Testing Instructions​

🌳 Specify Camera DTBO in U-Boot​

🎛️ Setup the media controller before camera streaming​

🎥 Start Camera Video Stream via GStreamer​

🎬 Launch GStreamer Pipeline​

✅ Check Media Controller​

🚨 Troubleshooting​

Check DTB Overlay in U-Boot​

Verify Camera Initialization​

Confirm Board and Camera DTB​

Check Available Video Devices​