Special COM Express identifies with RFID By Christine Howe

Editor’s note: The terms Computer-On-Module (COM) and System-On-Module (SOM) are often used interchangeably adio Frequency Identification (RFID) within the embedded industry. systems enable object tracking without physical touch. In applications such R quickly. And since many installations are consumer-related, as inventory management, manufacturing, economics drive cost and size metrics. automotive toll roads, and others, RFID readers need to be small and cost-effective. Although RFID systems need to be high-performance in Additionally, the readers need to pack a order to quickly access and process data gathered from tags processing punch because wirelessly reading positioned on the various tracked elements, power consump- tion must also be kept to a minimum. In addition, high-speed, large amounts of data per unit time demands high-capacity data throughput is absolutely essential for RFID high processing and I/O capabilities. In this systems, and in the existing RFID system a current-generation example, an existing RFID system is slated for 32-bit, 33 MHz PCI bus tops out about 1 Gbps maximum upgrade, and the choice between Computer- inter-card data throughput. Other requirements include Gigabit On-Module standards includes ETX and COM for high-speed remote control for updating and con- trolling the embedded appliance, along with Serial ATA drives Express. In the end, the newer standard is for fast, efficient data storage, and 2.0 compliant USB for fast chosen because it offers higher performance peripherals. and plenty of growth potential. Future system needs also indicate that the data requirements will grow along with the number of tracked elements (such As Radio Frequency Identification (RFID) systems become as the volume of automobiles on a toll road). Today’s RFID more popular for tracking inventory, automobiles on toll embedded design must also transition to embedded dual core roads, or just the day-to-day flow of objects, it’s inevitable processors as soon as they are available. Having integrated that smaller, faster, and more cost-effective systems are graphics capabilities that can support simultaneous inde- needed. Designing a very compact, low-profile embedded pendent dual displays is a likely future upgrade, as access to appliance that will serve the many cost-sensitive RFID end database or other visual elements can correspond to the data users requires a modular configuration that meets today’s tracked by the RFID reader. system needs while providing growth potential for future applications and I/O requirements. The ideal solution for the design would be one that can transition from legacy to new technology quickly and eas- We start with an existing RFID reader design that was ini- ily without causing too much disruption in terms of form, tially based on a full-custom motherboard. The new design fit, and function of the whole RFID system. Although it will for the embedded appliance has a number of new require- take some time to develop the custom elements of the sys- ments, including getting to market quickly. The ideal solu- tem, starting on the software as quickly as possible mandates tion will be upgradeable and scalable to support product line an easy-to-use evaluation platform. The process of designing expansion and revisions. Instead of custom hardware, mod- application-specific hardware and software must also not be ular electronics such as Computer-On-Module (COM) are cost prohibitive or consume more time than that of doing a investigated due to features, vendor selection, and growth full custom design. And finally, choosing a COM industry potential. standard that has sufficient vendor selection should assure availability of products and resources from reliable sources. Technical system requirements RFID readers are characterized by the need for compactness, Possible solutions low cost, and performance. In a typical toll road application, for So many options for small embedded appliances are now example, five or more booths need to be able to process RFID available that it is difficult to fully understand what fits tags from tens of vehicles per minute. Considering that the tags where, until one compares the options side by side. This contain credit card, personal ID information, and a myriad of definitely is the case for two of the more popular COM other data, the data processing and I/O requirements add up form factors: ETX and COM Express. While ETX is

Reprinted from PC/104 Embedded Solutions Fall 2005 PC/104 Small Form Factor & System-On-Module Selection Guide considered by many to be the de facto COM standard, the equipped with onboard USB, graphics, and audio. ETX mod- recent PCI Industrial Computer Manufacturers’ Group ules are mounted on an application-specific carrier board (PICMG) embedded COM Express standard adds new much like an integrated circuit component, plugged into a capabilities straight from the desktop and server markets host site that consists of four low-profile surface mount con- – including faster I/O, serial fabrics, and flexibility (refer to nectors. the endnote: What are Computer-On-Modules?). The ETX carrier board provides the drive electronics and To achieve the greatest flexibility in the design of this updated physical connectors for the previously mentioned integrated RFID system it is necessary to migrate away from a full cus- I/O that originates on the ETX COM. Additional I/O and tom design. The logical choice here is a modular design based application-specific subsystems may be integrated on the car- on an off-the-shelf COM product and a customizable base rier board designed as PCI or ISA bus peripherals. However, card carrier board. Based on the requirements detailed above, the constraints of these legacy busses represent limitations we can narrow the selection down to two industry standards that are not compatible with the technical requirements of – ETX and COM Express. The benefits to an RFID system the RFID system application design being considered. using modular designs are shown in Figure 1. For one thing, the PCI bus is only the 33 MHz variant (as opposed to 66 MHz) which constrains data communication speeds. Additionally, next-generation I/O such as PCI Express is not available.

COM Express: Forward-looking COM Express is the new PICMG standard for COMs. It is based on serial differential signaling technology and incorpo- rates interfaces including PCI Express, Serial ATA, USB 2.0, LVDS, and Serial DVO (Digital Video Output). COM Express modules provide the highest available performance on the smallest standards-based state-of-the-art embedded modules. Additionally, by following the modular concept for embedded design, COM Express modules safeguard R&D investments and lower the total cost of ownership. These core features of the COM Express specification are in line with the technical requirements of the RFID Figure 1 embedded appliance design that we are considering.

ETX: Legacy interoperability COM Express modules, Most ETX component SBCs (95 x 114 mm) are pre- such as the ETXexpress- dominantly x86-based solutions, following on from their PM from Kontron shown in introduction by Kontron (formerly JUMPtec) in 2000. Figure 3, support the following: Today there are ETX modules based on STMicroelectronics’ STPC ■ Up to 32 PCI Express lanes Figure 3 Elite and AMD’s with 80 GBps aggregate processors, all the bandwidth way up to the ■ External x16 PCI Express graphics (a growth opportunity high-performance for the RFID design) Pentium M pro- ■ Up to four Serial ATA-300 links with 600 MBps cessor 745. One such aggregate bandwidth example of an ETX COM is ■ Up to three 1-Gbps Ethernet ports, with provision for the ETX-PM from Kontron 10-Gb Ethernet in the future Figure 2 as seen in Figure 2. ■ Up to eight USB 2.0 ports ■ Up to two channels of LVDS ETX embedded modules are a perfect solution for embedded ■ Up to two channels of Serial DVO (a growth opportunity applications that require full PC functionality and high per- for the RFID design) formance CPUs. These COMs offer a complement of PC/AT interfaces such as keyboard, serial, parallel and IDE. ETX The RFID design must facilitate easy transitions from meets the flexibility requirement of the RFID design being legacy interfaces and performance to next generation technol- considered in this example. Most ETX modules also come ogy. The developers of the COM Express specification have

Reprinted from PC/104 Embedded Solutions Fall 2005 PC/104 Small Form Factor & System-On-Module Selection Guide Special Type 3: By eliminating the IDE interface available in pinout Type 2, two additional Gigabit Ethernet interfaces are made taken this into consideration. The COM Express standard has available. defined five different pinout options, as shown in Figures 4-8. These pinouts include:

Type 1: This pinout option is best suited for minimal, low- cost systems. It offers Gigabit Ethernet, LPC (), Serial ATA, PCI Express, USB 2.0, VGA, LVDS, TV, Power Management, GPIO, and other miscellaneous I/O.

Figure 6

Type 4: This option is similar to Type 2 except there is no PCI. This allows for an additional PCI Express resulting in a total of 32 open PCI Express lanes.

Figure 4

Type 2: Although not as minimal as Type 1, this pinout option represents the “baseline” COM Express. It offers both legacy and next generation interfaces. This option delivers all of the elements of Type 1 plus IDE, PCI Express Graphics, and PCI.

Figure 7

Type 5: This is the “legacy free” pinout type. Here there are no IDE and no PCI. These are instead replaced with PCI Express (32 lanes total) and Gigabit Ethernet ports (up to 3 GigE ports).

ETX vs. COM Express comparison The advantages of ETX are similar to those of PC/104: Figure 5 legacy interoperability with desktop PC peripherals and

Reprinted from PC/104 Embedded Solutions Fall 2005 PC/104 Small Form Factor & System-On-Module Selection Guide puting technology companies are next-generation modules ideally suited to advanced applications such as the RFID solution being considered here.

Both ETX and COM Express modules are very small and highly integrated, although COM Express uses lower profile inter-board connectors that allow a slimmer implementation in the RFID design. And both alternatives offer flexibility as modular COM solutions. But with the newly available PCI Express lanes available under the COM Express stan- dard, modules built to meet the standard will be able to eliminate any data throughput bottlenecks that previously existed. PCI Express graphics and Serial DVO also represent advancements in embedded computing technology that are newly available for semi-customizable solutions. Table 1 pro- vides a feature-by-feature comparison of the ETX and COM Express standards.

Designer’s choice Figure 8 Based on the findings discussed in this article, it can be con- cluded that COM Express products represent the best fit in software. Additionally, ETX is a COM form factor with all this RFID application. Not only would COM Express prod- the benefits of long-life carrier board technology. Although ucts deliver the processor and core PC performance required ETX modules will continue to represent the standard for cus- for today’s design, but the standard has made room for yet-to- tom designs, the COM Express products that are currently be-released advances including, but not limited to, dual core being introduced by some of the leading embedded com- processors, faster SATA drives, and video.

Table 1

Reprinted from PC/104 Embedded Solutions Fall 2005 PC/104 Small Form Factor & System-On-Module Selection Guide Special

What are Computer-On-Modules? Computer-On-Modules (COMs) are embedded modules based on COMs. Either a “touch-up” of the carrier board that provide all of the needed standard computing function- or a simple update to the replacement module is all that is ality onboard, while custom features are integrated into the required. Products based on embedded modules are highly design of the base card called a carrier board. This two- scalable and have longer life cycles than those based on board separation allows for higher flexibility in the mechan- other alternatives such as full custom designs. ics of the carrier board because it is the custom-made part tailored to meet the unique needs of the system. A compari- son between custom motherboards and COMs is shown in the figure. Because the COM mezzanine modules are fully interchangeable within the same module family, flexible processor choices and upgradeability are maintained.

An upgrade to the next generation of processor and/or level of graphics capability is as simple as changing the embedded COM module. The total design time for the car- rier board is very short compared to a full custom design cycle. This minimizes the associated development costs and ensures that the end product will get to market quickly. Parts obsolescence issues also are easily addressed for systems

Building on the fundamental benefits of using a Computer- Christine Howe is the Product Marketing Manager of On-Module solution, benefits of using COM Express prod- Kontron America’s Embedded Modules EPC. She has more ucts include: than five years experience working in the embedded com- puting technology industry and holds a Masters of Business ■ Enabling faster time-to-market and cost-effective Administration, Marketing Management degree from customization alternatives California State University, Hayward. ■ Better form/fit/function while minimizing current and future design risks For further information, contact Christine at: ■ Lower product life cycle costs through module scalability Kontron America – Bay Area and interchangeability 3988 Trust Way • Hayward, CA 94545 ■ Defines dense footprint for ease of integration with other Tel: 510-732-6900 • Fax: 510-732-7655 subsystems in embedded solutions E-mail: [email protected] ■ PICMG standard accepted worldwide Website: www.kontron.com

Reprinted from PC/104 Embedded Solutions Fall 2005 PC/104 Small Form Factor & System-On-Module Selection Guide