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Tiny ARM7 system runs uClinux

Apr 1, 2005 — by Henry Kingman — from the LinuxDevices Archive — views

Another extremely small embedded Linux system based on Digi's RJ-45 jack-sized ConnectME has surfaced. Atmark-Techno's miniscule Armidillo-J, available now in Japan, runs a little-endian uCLinux 2.4.22 kernel, and is available with several carrier board, case, and firmware image options.

(Click for larger view of Armadillo-J)

Earlier this week, we covered Kleinhenz Elektronik's Picotux, which runs a big-endian uClinux kernel and features a very small carrier board with a serial port and pins for five GPIO lines, along with the Digi ConnectME module's built-in RJ-45 port.

The developer version of the Armadillo-J's carrier board has a D-sub serial connector and a power connector


Like the Picotux, the Armadillo-J is based on Digi's ConnectME, which in turn is based on a NetSilicon NS7520 SoC (system-on-chip) with a 55MHz ARM7TDMI core. The ConnectME has 2MB of Flash, and 8MB of SDRAM. However, the Armadillo-J is available with a slightly larger carrier board, measuring 2 x 1.5 inches (50 x 37.5mm). Additionally, the Armadillo-J offers the choice of 3.3V power input via its power connector, or PoE (power-over-Ethernet).


Block diagram of the Armadillo-J

The Armadillo-J's carrier board is available in a developer version (shown at the top of the page) that features a 9-pin D-sub RS-232 serial port and a power connector jack. The production version, shown below, offers pin headers instead.

The production version of the Armadillo-J features pin headers instead of serial and power connector ports


The Armadillo-J's plastic case is also available with or without connector cut-outs. The case measures 3.1 x 1.8 x 1 inches (79 x 45 x 26mm).

uClinux imlementation

According to Atmark-Techno's Yasushi (Yashi) Shoji, Armadillo-J's “Armadillo Linux” is based on a 2.4.22-uc0-aj1 kernel. The company started from an NS7520 uClinux port made by FS Forthe-Systeme, a German embedded company that was acquired earlier this week by Digi (which makes the ConnectME, and also owns NetSilicon).

Atmark-Techno started with FS-Forthe's uClinux port, but made a few alterations, according to Shoji. “The boot sequence is totally different. We use a port of the Hermit bootloader, instead of FS's way.”

Additionally, Atmark-Techno fixed several bugs, Shoji says. “FS's port had some serious bugs in serial and network driver code, which [have] been fixed. We also added a GPIO driver. All fixes are available on our site, and most, if not all, of the fixes [have been] sent to uClinux-dist mailing list, and merged upstream, if I recall correctly.”

Firmware options

Atmark-Techno offers several firmware images for the Armadillo-J, including a simple “default” image, as well as a “base image” that includes the msh shell and other busybox components, Shoji says. The images are available pre-built, or as source code that can be easily built within uClinux-dist, according to Shoji.

Availability

The Armadillo-J is available immediately from resellers in the US, Japan, and Thailand, with typical pricing of $275 in single quantities. The Armadillo-J was originally introduced in October, 2003.


 
This article was originally published on LinuxDevices.com and has been donated to the open source community by QuinStreet Inc. Please visit LinuxToday.com for up-to-date news and articles about Linux and open source.



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