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Getting Started with DK AM62L DC#

This guide is intended for first-time users of the Development Kit DK AM62L DC and provides help in getting the board up and running. Each Development Kit includes a BL AM62L board and accessories such as a power supply and a USB-to-serial converter.

To bring the board up to the Linux prompt, it can be started from three sources, selected with the Force Recovery switch S1:

  • eMMC (S1 = 0) — the pre-installed system on the internal eMMC. This is the default, see Boot from eMMC.
  • DFU (S1 = 1) — used to transfer an image over USB and run it from RAM, see Boot from DFU-USB.
  • SD card (S1 = 1) — used to set up or update the device. With S1 = 1 the board enters DFU mode first and falls through to the SD card, see Boot from SD card.

Note

The standard setup is S1 = 0. This means that on power-up, the board starts booting from the eMMC.

Required Items#

Some parts of this guide require additional items in order for the tasks to work.

  • SD card image (*.wic) from our release page (see under Assets → Other) or from your own Yocto deploy folder
  • Bootloader images from our release page:
  • tiboot3.bin
  • tispl.bin
  • u-boot.img
  • or flash-emmc.bin, a combination of the three images above
  • USB OTG cable for booting over DFU
  • Terminal program for the serial console

bl-ti-am62l-top

Layout and Connectors#

BL AM62L Connectors Layout

The connectors and interfaces used in this guide:

  • X101 — Power, connector for the 24 V power supply
  • X201 — Console, connector for the serial debug console
  • X601 — SD card, SD card slot for storing data. Booting an external operating system from it is only possible in recovery mode.
  • S1 — Force Recovery switch, forces recovery mode (DFU first, then SD card)
  • X1301 — USB OTG interface

Connecting Power and Debug Cable#

Connect the power supply that came with the Development Kit and plug it into the X101 (Power) socket on the board. Do not connect the power supply to the mains yet. The power socket on the board is on the left next to the two USB ports and has only two pins.

Now take the USB cable from the box and plug the USB Mini-B plug into the USB Mini-B socket named X201 (Console) on the left side of the board. This connector is not a USB port, but a serial port that gives access to the debug console of the BL AM62L (/dev/ttyS0). It allows you to communicate with the operating system without setting up a network first. The other end of the cable (USB type A) has to be plugged into the USB-to-serial adapter that came with the Development Kit, which in turn is plugged into a computer.

bl-ti-am62l-top-debug-dongle

Boot from eMMC#

With the Force Recovery switch S1 set to 0, the board boots the system pre-installed on the internal eMMC. This is the default and needs no further setup.

Before turning on the power for the BL AM62L, make sure the USB-to-serial adapter is plugged into the computer and that a terminal program is running on the port the adapter is registered at. On Linux this is usually a ttyUSB device, on Windows a COM port. The serial settings are 115200 8N1.

Once this is set up, the board can be powered on. Text should appear in the terminal program, which means the operating system is starting. After a short wait the output stops and a login prompt appears. The image below shows an example of what you should see in the terminal program.

BL-ti-am62l-Terminal-Wnd-Login

To log in, use the user root. No password is required.

Once logged in, a good first step is switching digital output 1 (DIO1) on and off. The pre-installed system ships with the libgpiod library and its service programs, so gpioset can be used to change the state of DIO1. The line is addressed by its label DIO1_OUT, so the GPIO chip does not have to be named — it is offset 0 of gpiochip2, see Digital IOs.

Configure DIO1 as an output and set it to 1 (on):

gpioset DIO1_OUT=1

The onboard LED for DIO1 should light up and signal that the output is now active. This single command configures the GPIO as an output and sets it to 1 in one go.

Turning DIO1 off works the same way, by setting it to 0:

gpioset DIO1_OUT=0

The LED for DIO1 should now be off again, meaning the output is no longer active.

Boot from DFU-USB#

To start in DFU mode, the board has to be in recovery mode: set the Force Recovery switch S1 to 1. The board then comes up in DFU mode and waits for an image over USB. The image can be loaded into RAM and run from there. How to transfer an image this way is described in Program Software on Kontron AM62L.

Boot from SD card#

In recovery mode (S1 = 1) the board always enters DFU mode first. To boot from the SD card instead, transfer a file over DFU that is not a valid first-stage boot image — for example tispl.bin instead of tiboot3.bin, which is the first-stage boot image expected by the ROM code. The ROM code cannot boot from it and falls through to the SD card immediately. The eMMC is ignored as long as S1 is set to 1.

Troubleshooting#

The BL AM62L board in the Development Kit comes with an OS pre-installed on the internal eMMC and is ready to go. If this is not the case, or if you only have the bare BL AM62L board, you can still get the board working by booting over DFU or by writing a pre-built image to an SD card and setting the Force Recovery switch S1 to 1.

Download one of the reference images from the KED BSP release page to get a base system. Unpack the release file, then unpack and write the *.wic file onto a blank SD card. If you are working under Windows, you might have to rename the file extension from *.wic to *.img to be able to use one of the many SD card writing programs available. Insert the SD card into the SD card slot of the BL AM62L board and plug in the power supply.

Then bring the board up from the SD card as described in Boot from SD card. The text described above appears in the terminal program, and you can log in and go through the GPIO example.

Building Your Own System#

If you want to build your own system for the BL AM62L, you have to use the Yocto-based build system to create your own system image. Please follow the KED Yocto BSP guide to set up and build your own system. For more information on the Yocto Project, visit the project's website, where you also find the reference manual.

After you have obtained or built a Yocto image, you can write it onto an SD card and then set up the device, or overwrite any existing OS with your own.

Writing Images to eMMC over U-Boot#

To write the boot image (bootloader and Linux) to eMMC via U-Boot, see Program Software on Kontron AM62L.

Writing Images to eMMC over Linux#

Writing the Bootloader to eMMC#

This section is intended for users who want to boot the device from the eMMC instead of the SD card, freeing up the SD card for other uses. To boot the DK AM62L DC from eMMC, a bootloader such as U-Boot has to be stored in the eMMC boot partition of the SoM. In addition, the eMMC has to be configured to boot from this boot partition.

Required Files#

  • image.wic – SD card image from Yocto, usually found in the deploy folder after a successful build.
  • flash-emmc.bin or the three bootloader files tiboot3.bin, tispl.bin and u-boot.img – bootloader for the eMMC boot partition, usually found in the Yocto deploy folder after a successful build.
  • u-boot.env and u-boot-redundant.env – U-Boot environment for the eMMC boot partition.

Preparations#

Now that you have the files, a few more steps are needed before you can write the bootloader to the eMMC of the DK AM62L DC.

  • Insert an SD card into the computer using a card reader.
  • Write image.wic to the SD card using an SD card writing program of your choice.
  • Once done, re-insert the SD card into the PC. If the image was written successfully, the FAT32 boot partition already contains the bootloader files tiboot3.bin, tispl.bin and u-boot.img, which can be used to flash the eMMC.
  • Optionally, copy the combined bootloader image flash-emmc.bin to the boot partition if you prefer to flash the bootloader as a single file.
  • Copy the U-Boot environment files u-boot.env and u-boot-redundant.env from the Yocto deploy folder to the boot partition. They are not included in the image and are needed in any case.
  • Set the Force Recovery switch S1 on the DK AM62L DC to 1.

Writing the Bootloader#

Everything has been prepared, now you can write the U-Boot files to the eMMC boot partition of the DK AM62L DC.

  • Insert the SD card into the DK AM62L DC, have the serial console ready and boot the board from the SD card as described in Boot from SD card.
  • Once the login prompt appears, log in with the user root.
  • Run the command lsblk and check whether the first partition of the SD card (mmcblk1p1) is already mounted, usually at /run/media/mmcblk1p1. If not, mount it to a folder of your choice and adjust the following commands accordingly.
  • Change to the boot partition, enable the eMMC boot partition and make it writable:
root@kontron-am62l:~# cd /run/media/mmcblk1p1
root@kontron-am62l:/run/media/mmcblk1p1# mmc bootpart enable 1 0 /dev/mmcblk0
root@kontron-am62l:/run/media/mmcblk1p1# echo 0 > /sys/block/mmcblk0boot0/force_ro
  • Then write the bootloader using one of the following options.

Option A: Combined bootloader image

root@kontron-am62l:/run/media/mmcblk1p1# dd if=flash-emmc.bin of=/dev/mmcblk0boot0 bs=1K conv=fsync

Option B: Separate bootloader files

root@kontron-am62l:/run/media/mmcblk1p1# dd if=tiboot3.bin of=/dev/mmcblk0boot0 bs=1K seek=0 conv=fsync
root@kontron-am62l:/run/media/mmcblk1p1# dd if=tispl.bin of=/dev/mmcblk0boot0 bs=1K seek=512 conv=fsync
root@kontron-am62l:/run/media/mmcblk1p1# dd if=u-boot.img of=/dev/mmcblk0boot0 bs=1K seek=2560 conv=fsync
  • The U-Boot environment is not part of the bootloader images. For both options, write u-boot.env and u-boot-redundant.env separately to their offsets:
root@kontron-am62l:/run/media/mmcblk1p1# dd if=u-boot.env of=/dev/mmcblk0boot0 bs=1K seek=8064 count=64 conv=fsync
root@kontron-am62l:/run/media/mmcblk1p1# dd if=u-boot-redundant.env of=/dev/mmcblk0boot0 bs=1K seek=8128 count=64 conv=fsync
  • Finally, make the eMMC boot partition read-only again:
root@kontron-am62l:/run/media/mmcblk1p1# echo 1 > /sys/block/mmcblk0boot0/force_ro

The bootloader should now be stored in the first boot partition of the eMMC. If you power off the device now, take out the SD card, set the Force Recovery switch S1 to 0 and power the device back on, the bootloader stored on the eMMC should be loaded and show up in the debug console.

If a system is already present on the eMMC, it will be started. If there is no OS on the eMMC, the bootloader will try to load the kernel image, fail, reset and start over in an endless loop.

Writing the System Image to eMMC#

The DK AM62L DC has an eMMC memory chip on the SoM, which can be used to boot a self-made system image. This frees up the SD card slot, which can then be used as data storage, for example.

Requirements#

  • image.wic – SD card image from Yocto, usually found in the deploy folder after a successful build.
  • A FAT32-formatted USB stick containing the image.wic file mentioned above.

Preparing the SD Card and USB Stick#

If you come from the previous section, you can re-use the SD card. Otherwise, you will first have to prepare an SD card before continuing with the next steps.

  • Insert an SD card into the computer using a card reader.
  • Write image.wic to the SD card using an SD card writing program of your choice.
  • Copy the image.wic file to the root of the USB stick.
  • Set the Force Recovery switch S1 on the DK AM62L DC to 1.

Writing the System Image#

Everything has been prepared, now you can write the system image file to the eMMC of the DK AM62L DC.

  • Insert the SD card and the USB stick into the DK AM62L DC, have the serial console ready and boot the board from the SD card as described in Boot from SD card.
  • Once the login prompt appears, log in with the user root.
  • Run the command lsblk and check whether the first partition of the USB stick (sda1) was mounted automatically, usually at /run/media/sda1. If not, mount it to a folder of your choice and adjust the following commands accordingly.

In this example the USB stick was detected during boot and its first partition was mounted to /run/media/sda1. Changing into this folder and listing the available files should show the system image (*.wic) file:

root@kontron-am62l:~# cd /run/media/sda1
root@kontron-am62l:/run/media/sda1# ls -la
drwxrwx---    2 root     disk         32768 Jan  1  1970 .
drwxr-xr-x    5 root     root           100 Sep  1 09:08 ..
-rwxrwx---    1 root     disk     465599488 Aug 18 12:20 image.wic

You can now write the system image to the eMMC using the program dd and the device name /dev/mmcblk0:

root@kontron-am62l:/run/media/sda1# dd if=image.wic of=/dev/mmcblk0 bs=1M conv=fsync

Now wait a few minutes until the complete image has been transferred. Once this is done, dd prints the number of blocks read and written and you are back at the command prompt.

Now power off the device, unplug the USB stick, take out the SD card, set the Force Recovery switch S1 to 0 and power the device back on to check that the system now boots from eMMC.

Troubleshooting eMMC Boot#

If nothing happens and the DK AM62L DC does not boot from eMMC, the eMMC probably contains no valid bootloader, or the eMMC boot partition was not enabled with mmc bootpart enable. Boot the DK AM62L DC from the SD card again (Force Recovery switch S1 set to 1) and repeat the steps in Writing the Bootloader to eMMC.

This concludes the getting started guide for the DK AM62L DC.