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RTEC10 is an index made up of 10 public companies which have revenue that is derived primarily from sales in the embedded sector. The companies are made up of both software and hardware companies being traded on public exchanges.

COMPANY PRICECHANGE
Kontron
7.81
4.577%
Adlink
1.54
2.388%
Advantech
2.32
1.505%
Interphase
1.61
-3.012%
Radisys
9.26
-1.016%
-   Performance Technologies2.100.000%
-   Enea5.630.000%
PLX
3.62
-3.209%
Mercury Computer
11.76
-2.931%
Elma
412.98
-0.476%
HIGH LOW MKT CAP
7.85
7.43
435.04
1.58
1.52
185.11
2.33
2.30
1,198.70
1.70
1.61
11.00
9.41
9.24
223.74
2.102.1023.34
5.635.54101.86
3.74
3.61
134.28
12.17
11.76
279.57
412.98
412.98
94.25
RTEC10 Index: 490.94 (1.11%)
RTEC10 is sponsored by VDC research

TECHNOLOGY IN CONTEXT

COM Modules

Toward a Unified Framework for Embedded Modules

Some rather minor modifications to the original PC/104 form factor may not only smooth the path from legacy ISA through PCI to PCI Express data paths in the same system, but also provide a way forward when future interconnect technologies appear.

JONATHAN MILLER AND RICK LEHRBAUM, DIAMOND SYSTEMS

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In April of 2008, the Small Form Factor Special Interest Group (SFF-SIG) unveiled a new modular standard for stackable expansion of single board computers. The SFF-SIG’s new standard, known as the Stackable Unified Module Interconnect Technology (SUMIT), implements a PC/104-like self-stacking bus based on the latest serial bus and interface technologies.

SUMIT defines the electrical and mechanical characteristics of a stackable expansion bus for single board computers and expansion modules. SUMIT defines two identical 52-pin connectors (“A” and “B”), which together carry up to 6 lanes of PCI Express, four USB 2.0 ports, ExpressCard support, a low pin count (LPC) parallel bus, SPI.uWire and SMBUS/I2C serial buses, and various power and ground lines. The signals carried on SUMIT’s A and B connectors, according to the soon-to-be-released SUMIT Version 1.3 specification, appear in Table 1.

The SUMIT specification defines three configuration alternatives based on having one (connector A), the other (connector B), or both the A and B SUMIT connectors present on the host single board computer (SBC). They are designated as follows:

• Configuration A — consisting of the SUMIT A connector, only

• Configuration B — consisting of both the SUMIT A and B connectors

• Configuration C — consisting of the SUMIT B connector, only

Combining SUMIT with PC/104

It should be emphasized that the SUMIT specification is independent of any particular form factor. That noted, a separate SFF-SIG draft specification defines a SUMIT-based stackable module format that offers backward compatibility with the PC/104 Consortium’s PC/104 module standard. Initially dubbed “Express104,” the standard is currently known as “SUMIT-ISM” where “ISM” standards for ”industry standard module.”

Basically, SUMIT-ISM features a PC/104-compatible board outline and mounting hole pattern along with SUMIT’s pair of 52-pin connectors (A and B) near the top edge. In addition, the PC/104’s 104-pin connector array is near the bottom edge just as it is in legacy PC/104 modules. The result is a compact, self-stacking, embedded computer module format that supports expansion via SUMIT’s PCI Express and other bus signals, along with PC/104’s ISA bus.

SUMIT-ISM thus enables the use of “legacy” PC/104 (ISA) expansion modules within SUMIT-based module stacks—a convenient way to include both PCI Express and ISA in a compact, rugged module stack. Additionally, SBCs can be designed with SUMIT-ISM bus connectors, allowing expansion with a choice of modules based on either the SUMIT bus configurations, a PC/104 (ISA) bus, or a combination of both.

Figure 1 shows the basic connector, board outline and mounting hole layout of the SFF-SIG’s preliminary SUMIT-ISM module format. For the purposes of this discussion, this version will be designated “SUMIT-ISM Type 1.”

While SUMIT-ISM builds a bridge from yesterday’s PC/104 module standard to tomorrow’s PCI Express requirements, it does not directly support modules that interface via the PC/104 Consortium’s 120-pin stackable PCI bus (also known as “PCI-104”). Use of PCI-104 modules in a SUMIT-ISM stack is possible, but it requires the addition of a dedicated PCIe-to-PCI adapter card to create the necessary 120-pin PCI bus.

Under the assumption that many system developers may prefer to incorporate today’s widely available, high-performance PCI-104 modules and PC/104-Plus modules (with their 104-pin ISA stackthrough connectors removed) in new designs that utilize SUMIT, we are proposing a SUMIT-ISM Type 2 module, which substitutes a PCI-104 (PCI) bus option for SUMIT-ISM’s PC/104 (ISA) bus option.

Put simply, SUMIT-ISM Type 2 builds a bridge from today’s PCI-104 (PCI) module standard to tomorrow’s PCI Express requirements. PC/104-sized (or larger) single board computers built with SUMIT-ISM Type 2 can thus be expanded via SUMIT (PCIe etc.) modules, legacy PCI-104 (PCI) modules, or both. Additionally, an adapter module could provide compatibility with legacy PC/104 (ISA) modules.

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