Small form factor boards head for the SUMIT -

Small form factor boards head for the SUMIT


SAN JOSE, Calif. — Details of an interface specification aimed towards next generation, low power, expandable single board computers (SBCs) were released at the Embedded Systems Conference here. The SUMIT spec covers a mix of high-bandwidth PCI Express lanes, USB ports, and lower speed multiplexed and serial buses which can be added to a variety of board form factors.

SUMIT is an electromechanical connectorization specification using two, 52-pin high-density (0.025-inch pitch) connectors with center ground blades for impedance, EMI, and dc ground return purposes. Each connector is optional depending on the target applications of a particular SBC.

The SUMIT type A connector contains one PCI Express x1 lane, three USB ports with a global over-current signal, low pin count (LPC) bus for expansion serial ports and other legacy I/O, SPI/uWire, and a general-purpose I2C bus that is typically connected to SMBus for x86 chipsets.

The lower speed buses are sen as enabling a smooth transition away from the long-standing ISA Bus for much of the embedded market that uses simple I/O for applications like switching on relays or low-rate data acquisition.

The SUMIT type B connector adds another PCI Express x1 lane and a x4 lane, primarily for storage/RAID, networking, video output or frame grabbers, high-speed acquisition, and scientific applications.

There are three valid configurations known as SUMIT-A, SUMIT-B, and for both connectors, SUMIT-AB. Form factor details are distinct from the SUMIT connector and pinout details, and are therefore left to those respective specifications, for example Express104 and Pico-ITX form factors.

“The small form factor area of the market appears to be one of the fastest growing segments, as evidenced by recent announcements,” said Colin McCracken, president, Small Form Factor Special Interest Group (SFF-SIG). “The SFF-SIG provides an incubator organization structure under which specification sponsors can easily form a working group and develop solutions to their portions of this rapidly-evolving segment, with full access to broad inputs and reviews from the SIG’s diverse global membership.”

SFF-SIG also released the Express104 specification which uses SUMIT on small, stackable, embedded computing modules.

SUMIT will work well with single-chip chipsets being released by several manufacturers for sub-10 Watt designs, and closely follows the trend of replacing parallel interfaces with high-speed serial interfaces.

SUMIT has resulted from the cooperation by SBC vendors, I/O vendors, chipset manufacturers, and integrators led by WinSystems Inc. (Arlington, TX), VIA Technologies Inc. )Taipei, Taiwan), VersaLogic Corp. (Eugene, OR), Octagon Systems (Westminster, CO), and Ampro Computers Inc (San Jose, CA).

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