ODROID-U3

The ODROID-U3 is a very low cost and high performance development platform based on an Exynos 4412 ARM Cortex-A9 Quad Core 1.7GHz CPU. It has 3 USB 2.0 ports and micro HDMI. The board has several accessories available through Hardkernel such as 10.1" and 14" LVDS LCDs (with adapters), Wifi and Bluetooth adapters, 1.8v serial adapter (recommended if you're going to be any debugging...actually, it's recommended anyway so you won't have to pay shipping twice when you realize you need it later), and an eMMC storage module.

Other features of the board include:

  • Mali-400 Quad Core Graphics accelerator
  • 1080p/720p video over micro HDMI
  • 3.5mm headphone/microphone jacks
  • 3x USB 2.0 Host ports
  • 1x USB 2.0 Device port
  • Micro SD
  • eMMC module
  • 83 x 48 mm base board size
Architecture
ARMv7 Cortex-A9
Processor
Samsung Exynos 4412 1.7GHz
RAM
2GB
SD
Micro SD
USB
3
Ethernet
10/100

SD Card Creation

Replace sdX in the following instructions with the device name for the SD card as it appears on your computer.

  1. Zero the beginning of the SD card: 
    dd if=/dev/zero of=/dev/sdX bs=1M count=8
  2. Start fdisk to partition the SD card: 
    fdisk /dev/sdX
  3. At the fdisk prompt, create the new partition:
    1. Type o. This will clear out any partitions on the drive.
    2. Type p to list partitions. There should be no partitions left.
    3. Type n, then p for primary, 1 for the first partition on the drive, 4096 for the first sector, and then press ENTER to accept the default last sector.
    4. Write the partition table and exit by typing w.
  4. Create the ext4 filesystem: 
    mkfs.ext4 /dev/sdX1
  5. Mount the filesystem: 
    mkdir root
mount /dev/sdX1 root
  6. Download and extract the root filesystem (as root, not via sudo): 
    wget http://os.archlinuxarm.org/os/ArchLinuxARM-odroid-latest.tar.gz
bsdtar -xpf ArchLinuxARM-odroid-latest.tar.gz -C root
  7. Flash the bootloader files: 
    cd root/boot
./sd_fusing.sh /dev/sdX
cd ../..
  8. Unmount the partition: 
    umount root
  9. Insert the SD card into the board, connect ethernet, and apply 5V power.
  10. Use the serial console (with a null-modem adapter if needed) or SSH to the IP address given to the board by your router.
    • Login as the default user alarm with the password alarm.
    • The default root password is root.
  11. Initialize the pacman keyring and populate the Arch Linux ARM package signing keys: 
    pacman-key --init
pacman-key --populate archlinuxarm

eMMC Module Creation

  1. Attach the eMMC module to the micro SD adapter, and plug that into your computer.
  2. Follow the above steps to install Arch Linux ARM, and boot the board with the eMMC still attached to micro SD adapter, plugged into the SD slot in the board.
  3. Re-flash the bootloader to the protected boot area of the eMMC module: 
    cd /boot
./sd_fusing.sh /dev/mmcblk0
  4. Power off the board: 
    poweroff
  5. Remove the micro SD adapter, detach the eMMC module, and connect the eMMC module to its connector on the board.
  6. Re-apply power the board.
  7. Use the serial console (with a null-modem adapter if needed) or SSH to the IP address given to the board by your router.
    • Login as the default user alarm with the password alarm.
    • The default root password is root.
  8. Initialize the pacman keyring and populate the Arch Linux ARM package signing keys: 
    pacman-key --init
pacman-key --populate archlinuxarm

HDMI audio

To enable audio over HDMI, add the following to your asound.conf: 

pcm.!default {
   type hw
   card 0
}
ctl.!default {
   type hw
   card 0
}

LEDs

ODROIDs have dual LEDs: a red power LED which is always on if power is supplied, and a blue LED which can be configured.

By default, the blue LED is a heartbeat LED, which flashes when the kernel is running. This can be configured in /sys/class/leds/led1/trigger.

To list available triggers: 

# cat /sys/class/leds/blue:heartbeat/trigger

Replace TRIGGER with one of the available triggers. This setting will apply instantly, but be lost upon reboot. 

# echo TRIGGER > /sys/class/leds/blue:heartbeat/trigger

To create a persistent configuration, edit or create /etc/tmpfiles.d/leds.conf: 

w /sys/class/leds/blue:heartbeat/trigger - - - - TRIGGER

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