What is Express104™?

FAQ

  1. What is Express104™?
  2. What is SUMIT™ technology?
  3. What interfaces are included with Express104™?
  4. Why did you select this complement of I/O for Express104™?
  5. Why do you support PC/104 as a "legacy option"?
  6. What applications suit Express104™?
  7. How many boards can be supported in an Express104™ stack?
  8. What direction can Express104™ boards be stacked?
  9. How does Express104™ automatically support more that one PCI Expansion board in a stack?
  10. What is special about the SUMIT™ connector?
  11. Can Express104™ modules work with EPIC and EBX boards?
  12. Is there a technical standards group supporting Express104™?
  13. Is there licensing required for Express104™?
  14. Does Express104™ support hot plug and hot swap?
  15. How soon will product be available?
  16. Where can I get more information and the latest specification?

What is Express104™?   Top
Express104™ is defined as a stackable, 90mm x 96mm size board utilizing the features of Stackable Unified Module Interconnect Technology (SUMIT™) that includes PCI Express, USB, SPI, I2C, and LPC Bus expansion. SUMIT™ is implemented with two, footprint-efficient, 52-pin, high-speed rugged Samtec Q2 connectors.

Express104™ systems are small, reliable, easy-to-use, cost-effective, and scalable as they provide a powerful building block for a variety of different applications. Express104™ boards can be stacked on top of each other to expand or customize system solutions. This reduces cost and bulk while increasing mounting and packaging options.

What is SUMIT™ technology?   Top
SUMIT is an electromechanical connectorization specification that integrates industry standard serial and legacy chipset expansion busses for next generation, small form factor products. Express104™ incorporates the Stackable Unified Module Interconnect Technology (SUMIT™) Type AB connectors. SUMIT™ defines the data signals, control, power plus their pin assignments on the connector as well as recommended guidelines for signal routing.

What interfaces are included with Express104™?   Top

  • Two x1 channels of PCI Express (including clock and card present)
  • One x4 channel of PCI Express (including clock and card present)
  • Three USB 2.0 channels
  • One ExpressCard channel
  • Two SPI/uWire channels
  • LPC interface with serial IRQ support
  • System Management Bus (SMBus) with SMD Alert
  • Reset and Wake On LAN (WAKE)
  • PC/104 (legacy option)

Why did you select this complement of I/O for Express104™?   Top
The goal of Express104™ is to support high-speed signals for the next 10+ years in order to facilitate the use by OEMs with long lifecycle needs. As technology continues to evolve into faster, smaller, and lower cost solutions, using SUMIT™ provides a solution for small, full-featured, next generation implementation for a wide range of the popular I/O busses. The I/O diversity of SUMIT™ provides a designer great flexibility for their application while balancing cost and space budgets.

Why do you support PC/104 as a "legacy option"?   Top
Even though Express104™ only needs SUMIT™ connectors, a special configuration has been defined to support PC/104 modules. Express104™ can then maintain legacy support for the vast number of PC/104 stacking expansion I/O modules and enclosures. This is done by defining the location and use of the legacy PC/104 connector which maintains its same placement, module physical dimensions, and mounting holes. The purpose of their support is to allow designers the use of these low-cost, industrial interface modules that are available worldwide. It will support interrupt driven I/O modules but not DMA.

What applications suit Express104™?   Top
Express104™ is a stackable, rugged, I/O-centric, multi-board solution for compact embedded systems such as medical, industrial, transportation, security, communications, MIL/COTS, machine control, and instrumentation applications. It incorporates high-speed PCI Express and USB serial buses that were developed for desktop and mobile environments plus supports other lower speed I/O buses as well. The key design goal is to be able to easily and cost-effectively interface to a wide variety of devices from a simple relay to high-speed video or networking infrastructure.

How many boards can be supported in an Express104™ stack?   Top
The total is a function of power usage by the boards in a stack. There can be boards in the stack for PCI Express, three boards for USB, plus SPI, I2C and LPC plus optional legacy PC/104 cards.

What direction can Express104™ boards be stacked?   Top
Express104™ boards stack up only. The reasons for this is to reduce cost and complexity of the support circuitry, plus allow support of faster signaling speeds. The goal of SUMIT™ is to support high-speed signals for the next 10+ years in order to facilitate the use by OEMs with long lifecycle needs. Faster signals are expected to emerge, including PCIe Gen2 and USB3. Meeting these signal integrity requirements was chosen as a higher priority than the option to stack in both the up and down directions, the latter of which imposes hardware that adversely degrades signal integrity. For legacy PC/104 customers, Express104™ offers the flexibility to stack Express104™ I/O cards up in one direction while stacking PC/104 cards in the opposite direction. Another approach is to invert the I/O stack so that the I/O cards are below the CPU card. Each of these depends on how the CPU card is designed.

How does Express104™ automatically support more that one PCI Expansion board in a stack?   Top
Each Express104™ board with a PCI Express x1 link utilizes an auto alignment topology up the stack. Links that are used on the I/O card are used and the remaining ones are simply shifted down through the connector positions to the top connector for use by the next board.

What is special about the SUMIT™ connector?   Top
The SUMIT™ connector system is able to handle high-frequency signals required by PCI Express and USB, plus is available off-the-shelf as a standard product from Samtec (New Albany, IN). Express104™ uses two, 1-bank connectors in a Type AB configuration and requires very little room on the board. The Samtec QMS/QFS Q2 series of connectors have been tested by their Signal Integrity division to verify that they can support Generation 2 PCI Express data rates of 5 Gbps.

Can Express104™ modules work with EPIC and EBX boards?   Top
Express104™ is defined as a 90mm x 96mm module with SUMIT™ stacking connectors on the board. Therefore, an Express104™ module can function as either a base single board computer (SBC) or I/O expansion module. Consequently, Express104™ expansion modules can also serve as stackable, rugged, I/O expansion modules for EBX, EPIC, and other custom-sized boards if SUMIT™ connectors are added.

The Express104™ specification includes mechanical connector placement for both EPIC and EBX boards for use with Express104™-based I/O expansion modules both with and without the PC/104 legacy option. None of the dimensions, I/O zones, or mounting holes of an EPIC or EBX board change, only the replacement of the 120-pin PCI connector with a 104-pin SUMIT™ Type AB connector pair.

Is there a technical standards group supporting Express104™?   Top
Express104 is administered by the Small Form Factor Special Interest Group (SFF-SIG). For further information, go to www.sff-sig.org.

Is there licensing required for Express104™?   Top
No, it is an open standard. However, use of the Express104™, SUMIT™ and/or SFF-SIG logos are prohibited if a company is not a member of Small Form Factors Special Interest Group.

Does Express104™ support hot plug and hot swap?   Top
No. Even though PCI Express can support this, Express104™ does not. This is because there are additional interface signals on the SUMIT™ connector and because the boards are held together by threaded spacers. It is necessary to power down the unit to add or replace any modules.

How soon will product be available?   Top
2008

Where can I get more information and the latest specification?   Top
Go to www.sff-sig.org.

Specification

What is Express104™?

Request a copy of this specification.

Press Release



Last updated April 11, 2008
© 2008 Small Form Factor Special Interest Group, Inc. All rights reserved.