ETX system modules plug into a baseboard that provides peripheral interfaces and connectors. Custom baseboards often are the typical route for designers.
But standard baseboards like Kontron's ETX miniBaseboard usually are sufficient, easier to obtain, and economical enough for production products (Fig. 1). The ETX miniBaseboard hides the ETX module on the bottom. It's slightly larger (130 by 155 mm) than an ETX board, and its standard set of connectors includes dual Ethernet and quad USB t along with a PCI slot and both Compact Flash and PCMCIA expansion. Pricing starts at $234.
ETX baseboards should work with any ETX module, such as Advantech's SOM-4455 SOM-ETX CPU Module (Fig. 2). This device uses AMD's 500-MHz Geode LX processor. It handles up to 512 Mbytes of small-outline dual-inline memory-module (SODIMM) double-data-rate (DDR) SRAM. It also has a 64-bit video processor on board along with four USB 2.0 ports, a 10-100BaseT Ethernet, and LVDS/LCD/AC'97 interfaces. And, it uses under 8 W. It costs $200.
Nexcom's ICES 120 ETX module sports an AMD Geode LX800 with up to 1 Gbyte of memory. For rugged environments, there's Adlink's ETX-G2, which is based on a 1.1-W AMD GX533 processor with up to 256 Mbytes of DDR SDRAM soldered on the board.
For more powerful modules, check out the XTX standard, which incorporates high-speed serial interfaces such as PCI Express and Serial ATA. XTX uses the ETX form factor, but with different connectors and pinouts. The XTX Consortium recently released its 1.1 specification. Ampro's XTX 820 is a typical module, with a 1.8-GHz Pentium M, as well as up to 1 Gybte of RAM and 100BaseT Ethernet. Prices start in the low $500 range.
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