AXON-IMX8MP TEVS Camera Usage Guide

Introduction

This article guides you how to get started using TechNexion camera modules on AXON-IMX8M PLUS Board.

Background knowledge needed

You must have the background knowledge to modify the kernel configuration, rebuild, and replace the kernel and the device tree source (DTS).

Supported Camera Modules

TEVI-OV5640 and TEVI-AR Series Cameras is no longer supported from Yocto 4.2

TEVI-OV5640 and TEVI-AR Series Cameras are only supported up to Yocto 4.0. If you want to use them, you can refer to Yocto 4.0 (Kirkstone) 2024Q1 Release.

Supported EDM-G Boards

Overview

• Connect debug console, power, and camera to board

• Prepare Yocto demo image for testing TechNexion camera

• Build Yocto

• Instructions for testing camera

• Trouble shooting

Connect debug console, power and camera to board

1. Prepare DC 5V/12V power cable to plug in. If using vizionlink must have DC 12V/minimum 3A power adapter by pin header 2 rows connector.
   (Note: AXON-WIZARD 5V powered by USB Type C)

2. Prepare UART cable (USB Micro B) connect to debug console of AXON-WIZARD.

3. There are two MIPI-CSI-2 connectors we refer to CSI1 and CSI2. These are 70-pin board-to-board connectors from Hirose. Below is a picture of TEVS camera with CSI1 connector shown.

   

Prepare Yocto demo image for testing TechNexion camera

The demo image contains the required device tree blobs and camera drivers to enable TechNexion cameras.
Prebuilt demo images can be available for download via TechNexion's server.

Image Download Link:
Supported Release List

You can find the prebuilt Images page in Release Notes, take YP4.2 2024Q3 for example:

Flash image to e.MMC or SD Card.

• Using 'uuu' to flash
  UUU

boot mode

Ensure the boot mode is configured as serial download mode.

• Using u-boot's 'ums' Command to Write Flash Storage over USB-OTG
  UMS

u-boot

The board must also boot from either e.MMC with a version of U-boot that has the ums command enabled.

Build Yocto

Supported TechNexion Linux kernel branch for TechNexion camera modules.

Fetch Yocto source
Build Yocto

Instructions for testing camera

Specify camera DTBO in u-boot

Auto detect camera

If you are using TEVI AR series or TEVS cameras, you can skip this section because it have auto detect camera function in u-boot.

1. Connect debug console cable to baseboard.

2. Power on board , and enter u-boot prompt mode.
   (keep hit enter when the "Hit any key to stop autoboot : " is shown.)

3. Specify camera dtb via 'dtoverlay' u-boot environment variable.
   for TEVS Cameras:

   u-boot=> setenv dtoverlay tevs

   for VLS3 Cameras:

   u-boot=> setenv dtoverlay vls

4. Continue boot process.

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

Start camera video stream via gstreamer

We can check whether camera have been link via v4l2 control command:

$ v4l2-ctl --list-device

Get the device number of camera capture device. As example we have camera on CSI1, that we can see /dev/video0 specify the capture device.

():
/dev/v4l-subdev0

():
/dev/v4l-subdev1

FSL Capture Media Device (platform:32c00000.bus:camera):
/dev/media0

mxc-isi-cap (platform:32e00000.isi:cap_devic):
/dev/video0

Specify the capture device you just get and start gstreamer to get video stream on screen:

$ gst-launch-1.0 v4l2src device=/dev/video0 ! video/x-raw, width=<res_w>,height=<res_h> ! imxvideoconvert_g2d ! waylandsink window-width=<x> window-height=<y> sync=false

imxvideoconvert_g2d

It not necessary to use or using videoconvert. Because IMX8MP have ISI to convert format.

Trouble shooting

Ensure camera device tree blob overlay(DTBO) is specified correctly in u-boot.
For TEVS cameras:

u-boot=> printenv dtoverlay
dtoverlay=tevs

For VLS3 cameras:

u-boot=> printenv dtoverlay
dtoverlay=vls

We can check whether camera have been initialized correctly.
For TEVS cameras:

$ dmesg -t | grep tevs
tevs 1-0048: tevs_probe() device node: tevs@48
tevs 1-0048: Version:24.9.0.1
tevs 1-0048: Product:TEVS-AR0144, HeaderVer:3, MIPI_Rate:800
tevs 1-0048: probe success
mx8-img-md: Registered sensor subdevice: tevs 1-0048 (1)
mx8-img-md: created link [tevs 1-0048] => [mxc-mipi-csi2.0]

Ensure camera device tree blob(DTB) is specified correctly.

$ dmesg -t | grep -i model
Machine model: TechNexion AXON-IMX8MP and WIZARD baseboard