Tiny board computer has CompactFlash form-factor

A UK-based start-up company called Cdata Solutions Ltd is debuting a very small SBC (single-board computer) for embedded system designers. According to company spokesman Paul Zawalnyski, it's targeted to low-volume developers, or OEMs doing proof-of-concept development, and is priced as low as $130 a pop in large OEM quantities.

Cdata's new SBC is a CF-format (compactflash) device, with a 1.68-by-1.48-inch footprint and a 200-mil Z-height (42-by-37-by-5mm). Running a peripheral-laden Motorola MFC5272 Coldfire microprocessor, and using Motorola's SPI serial bus for system control, the tiny board packs 32MB of 7.5ns access-time SDRAM, and 8MB of 90ns flash.

Here's what's neat: additional I/O is achieved by using standard CF cards! With these, you can add connectivity functions using Bluetooth, Ethernet or USB, for example. Or, you could add additional RS-232, RS-422, or RS-485 ports, or lots of parallel digital I/O.

Other third-party CF cards could add A/D and DAC functions to your mini-system. You could even equip one of these CF systems with cellphone functions or GPS location functions. How about adding a mini-hard disk, or a digital camera? It's all possible through the CF Bus's standard 50-pin connector.

The diminutive SBC is also a low power device, but not exactly power-stingy for something so small. It pulls about 200mA while its Coldfire CPU clocks at 40MHz (from a 3.3V supply). That's about two-thirds of a watt of dissipation. Even at that power level, though, this little board should find a home in any number of portable designs.

Bus extension
For those of you who want to build miniature expanded system empires, up to eight devices can be integrated into a system using a Bus Extension Unit; it looks like a CF Type II device.

Based on an FPGA, the system's bus expansion connector provides 3.3V at up to 500mA from an internal switching supply, affords SPI system control, and gives you access to CE and Expanded CE signals.

A 10-slot development motherboard offers eight slots for expansion, with socket spacings for Type II Compact Flash cards (it will accommodate Type I and II CF Cards, or even Type III cards, by not populating an adjacent connector). The CF SBC requires the bus expander when used with the motherboard.

On the software side, the SBC runs the royalty-free uCLinux v2.4 OS. Cdata Solutions also supplies a boot loader supporting third-party RTOSes. With POSIX, you get the full complement of TCP/IP protocols, including UDP, ICMP, ARP, IGMP, DNS, FTP, TFTP, HTTP, DHCP and Telnet.

Penguin power
For software development, Cdata's CF-based flash SBC provides an RS-232 interface, and access to Motorola's BDM (Background Debug Mode) signals across a 20-pin BDM connector. The header bus provides Vcc and ground lines, provides 5V to 10V, and gives access to the FPGA's programming signals.

A development kit that includes one CF SBC, the bus expander card, the 8-slot motherboard, and the RS-232/BDM header costs less than about $1,000. All of Cdata's software development tools are free, including GNU C and C++ cross development tools.

- Alex Mendelsohn
eeProductCenter