Arietta G25

The Arietta G25 is a tiny (53x25mm) ARM system powered by the Atmel AT91SAM9G25 ARM9 SoC. It is available with either 128MB or 256MB RAM, and provides a host of connectivity including:

  • 1x high speed USB host/device over the micro USB port
  • 3x UART
  • 2x I2C
  • 1x SPI with 3x chip select lines
  • 4x PWM
  • 4-channel 10-bit ADC
  • SSC/I2S audio interface
  • User configurable button and LED
Atmel AT91SAM9G25 400MHz
Micro SD

Install to a micro SD card

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

  1. Start fdisk to partition the SD card:
    fdisk /dev/sdX
  2. At the fdisk prompt, delete old partitions and create a new one:
    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, press ENTER to accept the default first sector, then type +100M for the last sector.
    4. Type t, then c to set the first partition to type W95 FAT32 (LBA).
    5. Type n, then p for primary, 2 for the second partition on the drive, and then press ENTER twice to accept the default first and last sector.
    6. Write the partition table and exit by typing w.
  3. Create and mount the FAT filesystem:
    mkfs.vfat /dev/sdX1
    mkdir boot
    mount /dev/sdX1 boot
  4. Create and mount the ext4 filesystem:
    mkfs.ext4 /dev/sdX2
    mkdir root
    mount /dev/sdX2 root
  5. Download and extract the root filesystem (as root, not via sudo):
    bsdtar -xpf ArchLinuxARM-arietta-latest.tar.gz -C root
  6. Move boot files to the first partition:
    mv root/boot/* boot
  7. Download the bootloader corresponding to the RAM size of the board (choose one of 128 or 256):
    wget[128|256].bin -O boot/boot.bin
  8. Unmount the two partitions:
    umount boot root
  9. Insert the SD card into the Arietta and apply power.
  10. Use the serial console, or connect via micro USB to your computer for ssh as detailed below.
    • 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

Host Communication

Arch Linux ARM has configured the rootfs with g_cdc which presents as a usb ethernet on the host. The device is configured with the static IP To connect via SSH, you will need to configure the host interface:

  1. Bring the interface up (typically enumerated as usb0)
    ip link set usb0 up
  2. Set the IP address
    ip addr add dev usb0
  3. Enable masquerading out your primary interface (eth0 use here, yours may be different)
    iptables -t nat -A POSTROUTING -s -o eth0 -j MASQUERADE
  4. Enable IP forwarding
    echo 1 > /proc/sys/net/ipv4/ip_forward

Install the AT91bootstrap package

  1. In order to receive updates to the AT91bootstrap bootloader, after logging into the system type:
    pacman -Syu at91bootstrap-arietta-[128|256]

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