SMALL FORM FACTOR BOARDS
Take the CoreExpress into a New World
CoreExpress represents an altogether new modular design the size of a credit card with a focus on the future. All legacy interfaces and functions have been eliminated.
HERMANN STRASS, LIPPERT EMBEDDED COMPUTERS
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Traditional computer systems follow two basic designs. PCs and servers in commercial, home or telecom applications are built on a motherboard with few or no plug-in boards. Such systems are mostly identical and there is normally no need for changes or upgrades during their (relatively short) lifetime. Industrial computers and some telecom systems are completely modular. The electronic components are all on plug-in cards, which are plugged into a passive backplane.
Industrial systems are orders of magnitude more diverse and have to perform for much longer periods than office systems. Initially most designs had the CPU, memory and other central parts on the carrier board. The fast pace of CPU development made it more economical to put the CPU (Computer) on the module for easy upgrade and system enhancement. This design is known under the name “Computer-on-Module” (COM). The user or system developer no longer needs to waste time with computer chip internals or interfacing, different types of memory, displays or I/O interfaces. He gets a tested and working system component. With such a product the user or system designer can concentrate on optimizing the application.
In recent years, embedded PC manufacturers have developed many small modular computer system platforms that can be embedded into functional devices and computer-on-module systems (COMs). These modules or boards were marginally smaller than traditional PC system components. They used available processor and chipset technology. Low power consumption and really small sizes for mobile applications were hard to achieve. The environmental and technical constraints were those of legacy PC technology. There are also speed issues with the existing COM platforms. They will experience problems with the high data rates of the newer and faster serial interconnects. The legacy connectors cannot transfer their high-frequency signals.
A New Approach
The CoreExpress design uses the latest chip and module production technology, creating an Advanced COM Specification (ACS). The CoreExpress specification targets a family of power-saving, compact and flexible modules that support transmission rates up to 5 Gbits/s and more in future implementations. This high-speed design is ready for future speed improvements of PCIe 2.0 (5 Mbit/s) and USB 3.0 (approx. 4.8 Gbit/s) without any changes. As the name implies, CoreExpress-compliant modules provide only the basic functional units of an embedded computer system, like the chipset (including the System Controller Hub), CPU, memory and voltage regulators for these chips. Additional management functions like power sequencing are handled by the System Management Controller (SMC). The BIOS software is stored in a flash memory chip. The module uses the well-established 220-pin high-density connector to connect to the carrier board or module. The carrier may be equipped with analog components, legacy and application-specific interfaces, as required (Figure 1).
The CoreExpress module at 58 mm x 65 mm (2.28” x 2.56”) is smaller than a credit card (Figure 2). This is currently the smallest embedded PC form factor in the industry. It weighs only 26g–just under one ounce.
The analog interfaces and circuit traces have been removed from the CoreExpress-ECO module to avoid signal interference between digital and analog elements interspersed on the same module. Components have been and will be selected with guaranteed availability for seven years or more. Industrial applications may typically run pretty much unchanged for even longer periods of time. They may be upgraded or expanded from time to time with the same or compatible qualified products. The CoreExpress design is modular, flexible and designed for long productive life, including upgrades, as required in most industrial and professional applications.
The discussion about climate change and the ever increasing energy prices make power consumption a very important factor for coming electronic appliances. The CoreExpress-ECO module with a maximum power consumption of 5W compares very favorably with typical COM Express modules at 20W or more in power consumption. Two examples might illustrate the significance of this reduction in power consumption by a factor of four. Take a chain of department stores with a few thousand branches. If there are, on average, 10 POS systems in each branch, the amount of energy to be saved by using low-power embedded systems can be enormous. Banks and insurance companies, which use lots of thin clients to access their data, also benefit from these potential savings. This results in a positive influence on the environment.
The CoreExpress modules are supported with an evaluation and development board or starter kit, based on the EPIC platform (Figure 3). This platform provides abilities to attach PC/104+, ISA and PCI components. The assortment of interfaces provides for flexible, application-specific system configurations. Operating system support is planned to include Windows, QNX and Linux.
Lippert Embedded Computers and their licensees (cooperation partners) are currently refining test procedures for interoperability testing. The CoreExpress license is free of charge. But products that carry the CoreExpress name and/or logo must be tested and certified for interoperability. Mere compliance and compatibility with pin assignments and signal levels, as is found with some other specifications or standards, is not enough. CoreExpress products will be tested for true interoperability with other certified products. This ensures interoperability not only at initial installation but also later during the product’s lifetime when add-ons or replacements are needed. This is required in industrial applications.
The first CoreExpress implementation, the CoreExpress-ECO, is based on Intel’s Atom platform and consists of the Z510 (1.1 GHz) or Z530 (1.6 GHz) CPU in 45nm feature size and the SCH US15W chipset. This Ultra Mobile PC (UMPC) is designed for minimum power consumption and maximum integration density. It supports all interfaces that are of importance for embedded applications.
The long list of CoreExpress interfaces includes these widely used serial interconnects:
• 5 – PCIe x1 (optionally 1 x4 PCIe and 1 x1 PCIe)
• 8 – USB 2.0 host (alternatively 1 client)
• 4 – SATA 2.0 (alternatively 1 PATA)
There are nine additional modern interfaces for applications that need graphics (SDVO & LVDS), digital I/O (8-bit SDIO/MMC), fast data transfer (Gbit MAC/GLCI), system management (SMB & SPI), fieldbus connectivity (CAN), audio (HD Audio) and for legacy I/Os on the carrier board, and LPC 1.0.
The SDVO interface from Intel can provide several different graphics transport protocols, like DVI, TV-OUT, HDTV-OUT and others. LVDS provides an additional single-channel graphics interface for flat panel displays. The digital gigabit MAC interface (GLCI) keeps analog circuits away from the CoreExpress module. However, it provides the possibility to use either a traditional copper Ethernet-PHY or an optical transmission line on the carrier board.
The heat sink for the processor has been designed to protect the CoreExpress module against Electro-Magnetic Interference (EMI). This greatly simplifies the system designer’s task when using a plastic enclosure (Figure 4).
The Fail-Safe-BIOS interface enables a new boot from protected BIOS if a BIOS update fails for any reason to facilitate a new start for an upgrade operation. No user intervention is needed for this task.
Management functions, like power sequencing and others, are handled by the System Management Controller (SMC). These SMC functions are building blocks for customer-specific condition monitoring and system performance monitoring applications.
CoreExpress modules find application in many market segments, like:
• Graphics (displays, cameras, machine vision)
• Communications (mobile servers, switches, routers)
• Medical (mobile healthcare)
• Processing (mobile embedded PC, POI, POS)
• Control (robotics, traffic supervision/control)
Graphics are very important in industrial systems to provide a visual representation of process flow, parts flow on an assembly, visual inspection of parts and similar operations. The flexibility and selection of graphics interfaces support such graphics-intensive applications. A broad selection of standardized communications interfaces meets the needs of complex industrial applications. In mobile healthcare, the small size, light weight and sensor interfaces meet the needs of such applications. Military applications benefit from the robustness of the small size, low power and mechanically simple design. Very small, high-performance CPUs and the small size make CoreExpress modules an optimal solution for processing and control applications.
The CoreExpress concept anticipates further component integration by several processor manufacturers who plan to integrate DRAM and a graphics controller with the CPU. When this is achieved, the only missing element for a highly integrated embedded PC is a really fast interface from the core to the I/O chipset. Multiple PCIe 2.0 lanes could handle the job, as well as a new generation of high-speed I/O bus or link. The designer can then create application-specific interfaces based on this ACS. Using an FPGA creates a very flexible design and secure type of copy protection for this type of system. The flexibility and functionality of the CoreExpress design will open other market segments in the future.
The CoreExpress ACS is a very promising solution for future COM (Computer-on-Module) implementations that has been especially designed for low-power applications using the latest semiconductor technology. The focus on the embedded PC’s core functionality while employing current high-speed interfaces, together with its ease of use, opens many new market segments for this concept.
With these interfaces, all on a single high-speed 220 pin connector, CoreExpress is well equipped for future chip technologies. Lippert Embedded Computers will also offer CoreExpress modules that are qualified for the extended temperature range E2 (-40° to +85°C). All CoreExpress modules will be constructed for passive cooling only.
This new design is able to handle the technological advancements and serves as a base for new and future embedded PC applications. Today electronic circuits have become extremely small and highly integrated. In many applications there is only a carrier board and a smaller plug-on module. A CoreExpress module does not handle legacy I/O. These functions can be implemented easily on the carrier board using USB bridges, if required. There are no analog signals on CoreExpress-ECO modules. The purely digital concept gives the user maximum flexibility when selecting components for the required interfaces. Problems of signal-level attenuation and similar analog issues are avoided with this “digital only” concept.
Although the first member of the CoreExpress family is based on the Intel Atom processor, it is by no means restricted to this platform. Future Small Form Factor (SFF) chipsets, which are suitable for industrial, medical or military applications, will also be supported. The CoreExpress design is flexible enough to support such embedded PC platforms.
LiPPERT Embedded Computers