Exponential growth in the use of mobile data worldwide has posed significant challenges to wireless operators. Fortunately, wireless technology has continued to evolve, and Long term evolution (Lte) has become the worldwide standard of choice to meet these challenges. the top 25 worldwide wireless operators have chosen to deploy Lte, which promises better use of the operator’s spectrum by improving spectral efficiency; this means more bits per hertz than previous technologies. supporting a successful Lte transition requires a number of innovations in base station soc design.

by Zhihong Lin, Strategic marketing manager, wireless base station infrastructure, Texas Instruments and Greg Wood, Application manager, wireless base station infrastructure, Texas Instruments

As Lte deployment becomes a reality, base station manufacturers are favoring systemon-chip (soc) architectures to keep operator network costs low while maintaining and improving service. texas instruments (ti) has developed a powerful and innovative new msystem-on-a-chip (soc) architecture designed to reduce costs for Lte products and enable manufacturers to benefit from cutting-edge base station technology.
TI’s multicore SoC architecture, called KeyStone, is designed to optimize WCDMA and LTE performance while reducing base station cost and power. For wireless base station applications, an essential part of KeyStone is the implementation of configurable coprocessors for the physical layer (PHY) or Layer 1 of the wireless standards. We’ll talk more about Keystone and TI’s TMS320TCI6618 solution shortly, but first let’s review LTE with particular focus on its PHY. LTE is the latest Third Generation Partnership Project mobile standard. LTE realizes major technology advances over 3G mobile technologies and offers peak downlink rates of at least 100 Mbps and peak uplink rates of at least 50 Mbps for the 20-MHz spectrum. LTE supports flexible channel bandwidths (1.4 – 20 MHz) as well as frequency-division duplexing (FDD) and time-division duplexing (TDD) to allow flexible deployment around spectrum ownership.
The foundation of the LTE communication protocol stack is the physical layer, sometimes referred to as Layer 1. The PHY layer is the basis of solid base station-tomobile device connectivity; without great wireless connectivity, calls drop, downloads fail, and videos stall. The PHY interfaces with Layer 2 (the media access control [MAC] layer) and Layer 3 (the radio resource control [RRC] layer) and offers data transport services to higher layers. PHY handles channel coding, PHY hybrid automatic repeat request (HARQ) processing, modulation, multi-antenna processing, and mapping of the signal to the appropriate physical time-frequency resources. LTE downlink PHY processing accepts data and control streams from the MAC layer in the form of transport blocks and begins processing by calculating the cyclic redundancy check (CRC) and attaching it to the transport block. If the transport block size is larger than the maximum allowable code block size of 6,144 bits, code block segmentation is performed. A new CRC is calculated and attached to each code block before channel encoding. Figure 1 illustrates the major functional blocks in the LTE downlink.
Turbo encoding provides a high-performance forward-error-correction scheme for reliable transmission; rate matching performs puncturing or repetition to match the rate of the available physical channel resource; and HARQ provides a robust retransmission scheme when the user fails to receive the correct data. Bit scrambling is performed after code-block concatenation to reduce the length of strings of 0s or 1s in a transmitted signal to avoid synchronization issues at the receiver before modulation.Various modulation schemes (quadrature phase shift keying [QPSK], 16 QAM [quadrature amplitude modulation], or 64QAM) are used for LTE layer mapping, and pre-coding supports multi-antenna transmission. Finally, the resource elements of orthogonal frequency-division multiplexing (OFDM) symbols are mapped to each antenna port for air transmission.
LTE Technology Evolution LTE leverages many advanced technologies used in 3G HSPA+ (high-speed packet access), like turbo coding, HARQ, and multi-antenna schemes. LTE offers a solution for 20 MHz of 100 Mbps on the downlink, 50 Mbps uplink and higher with multi-antenna signal processing schemes. TI’s TCI6618 solution supports two sectors 20 MHz, 2×2 multiple input, multiple output (MIMO) solution of 300 Mbps downlink and 150 Mbps on the uplink, with signal processing overhead for value add and advance algorithms. In addition, LTE uses OFDM and both downlink and uplink multiple-input/multiple-output (MIMO) technology to provide significant performance improvements over 3G systems. OFDM transmission – LTE uses OFDM for radio transmission, providing a robust transmission mechanism with protection against degradation from severe channel conditions, narrow-band co-channel interference, and intersymbol interference and fading. It also delivers high spectral efficiency and low sensitivity to time synchronization errors.
LTE downlink processing uses multicarrier OFDM transmission with a cyclic prefix. In the uplink, wide-band single carrier OFDM transmission with a cyclic prefix reduces the variation in the instantaneous power of the transmitted signal.
The Fast Fourier transform (FFT) provides low complexity and efficient implementation for OFDM modulation and demodulation.
MIMO technology – Smart antenna technology using MIMO (multiple-in/multiple-out) antennas is adopted in LTE at both the transmitter and receiver to improve performance. MIMO offers significant increases in data throughput and coverage without additional bandwidth or transmit power, providing higher spectral efficiency and link reliability against fading. Figure 2 (on left) illustrates the LTE 2×4 uplink MIMO channel model and receiver handling. Multiple antenna uplink MIMO receiver techniques can help increase the signal-to-noise ratio. Maximum-ratio combining (MRC) is an effective antenna-combining strategy when the receiver is primarily impaired by noise. In interference-dominate-channel conditions, a minimum mean square error (MMSE)- combining technique is a better approach to determine the antenna weighting vector that minimizes the mean square error. Floating-point implementations of MMSE MIMO equalization can significantly reduce computational complexity and provide high performance, resulting in an efficient LTE MIMO receiver.

TCI6618 – the LTE enabler
The TCI6618 SoC is a member of TI’s TMS320C66× DSP multicore generation. Based on TI’s new KeyStone multicore architecture, it is designed for high performance wireless infrastructure applications and provides a perfect fit for LTE design challenges. Figure 3 illustrates the features and processing elements of the device. TI’s KeyStone SoC architecture provides highest throughput and future-proof architecture for LTE and its continuous technology evolution. Its multicore SoC architecture--the TCI6618 has four 1.2-GHz C66x cores that support both fixed- and floating-point arithmetic operations builds upon TI’s field-proven multicore DSP platforms and includes an innovative new floating-point architecture and coprocessors for 4G systems. Adding to the computational improvements are innovations to the backplanes and internal data movement, which are critical to achieving full performance from a high speed 4G SoC.
The KeyStone multicore architecture is the first to provide a high-performance structure for integrating reduced instruction set computer (RISC) and DSP cores with application-specific coprocessors and I/O. KeyStone also is the first multicore architecture that provides adequate internal bandwidth for nonblocking and zero-delay access to all processing cores, peripherals, coprocessors, and I/O. A rich set of hardware accelerators reduces the LTE system latency and frees up CPU resources to achieve optimal LTE system capacity and competitive differentiation. TI also provides LTE PHY software, offering building blocks for customer PHY solutions that are highly optimized for the C66× cores.
The TMS320TCI6618 offers the most robust hardware platform combined with a development ecosystem that includes fully optimized LTE PHY library software. What is more, platform development software accelerates development efforts to enable best-in-class LTE PHY solutions to customers.

The article has been provided by Farnell in cooperation with Texas Instruments.
For more information visit the page: www.element14.com
All products are available at www.farnell.com

The highly integrated 2nd generation of Intel® Core™ i3/i5/i7 processors will populate all major standard embedded form factors, ranging from small-form-factor to high-performance designs. In addition to extended scalability, optimized power consumption and improved graphics performance, target applications will benefit from the new processors’ high level of integration, including memory and PCI Express controllers as well as processor graphics. The new platforms based on 2nd generation Intel® Core™ processors will also incorporate Intel® Advanced Vector Extensions (Intel® AVX). This accelerates scalar-based operations required for imaging applications in industrial automation, medicine and military projects as well as floating-point intensive applications, such as high-performance embedded computing (HPEC). Additionally, Intel® Turbo Boost Technology 2.0 automatically shifts or reallocates processor cores and processor graphics resources to speed up performance, optimizing a workload to give users an immediate performance boost whenever possible based on thermal headroom. To unleash the full potential of the new processor architecture, OEMs can now benefit from these enhancements on a wide portfolio of standardized and proven platforms to minimize design risk and speed up time-to-market.

The 2nd generation Intel® Core™ processor family brings huge improvements in processing power, graphics performance and power consumption. Further enhancements to power and a smaller footprint make it the ideal choice in 2011 for upgrading nearly all existing x86 platforms. But what is it exactly that makes the new processors so attractive?

Advanced graphics performance
The 2nd generation Intel® Core™ processor family integrates more capabilities than ever before. As well as incorporating a memory controller (with ECC support) and PCIe 2.0 (5 GTps), the latest processor now includes an extremely powerful graphics unit on a single die. Based on Intel’s new “visibly smart” micro architecture, the new processor line doubles the graphics performance of its predecessors and - for the first time in the embedded market - offers 2-D and 3-D graphics performance with OpenGL and DirectX10 support on the level of dedicated graphics cards. Thus, two high-resolution HD video streams can play simultaneously, allowing cost-effective multi-display solutions with just one space-saving hardware platform without expansion cards. For innovative infotainment solutions, they also support the new 3D BluRay technology making them fully prepared for the latest media formats.

Particularly energy efficient
As the GPU has now also been manufactured in 32 nm process technology, the new generation of Intel® processors is particularly energy efficient, with energy consumption being reduced by a factor of five as compared to the discrete graphics in the former processor generation. This is because the sixth generation graphics core now offers dedicated silicon for media processing, including dedicated units for graphics functions such as texturing, vertex processing, rasterization and Z-buffering, as well as a hard-wired transistor block that handles video tasks alone. This enables two advantages, first commonly-used graphics processing functions as well as transcoding of videos are outsourced to fixed function units and are thus significantly accelerated. Second, the energy consumption is also kept as low as possible since the hard-wired processing units work significantly more efficiently than possible for processor cores or programmable shader units. Application developers will benefit from significantly improved graphics performance and high energy efficiency.
(1) Error Correcting Code memory is available only on Intel® Core™ processors which come in a Ball Grid Array (BGA) Package and these SKUs were specifically developed by the Intel® Embedded and Computing Group.

Highly integrated
A high level of integration is possible due the 22% reduction in processor footprint. This makes the new generation of Intel® processors an optimal choice to bring quad-core performance into designs that until now were based on dual-core processors. So a differentiation has to be done regarding the term small form factor designs. Some form factors like COM Express™ basic or 3U blade systems such as CompactPCI® or VPX can now host quad-core processors and can be described as small form factor designs in this context. Nevertheless, the thermal envelope of the processors still requires adequate dimensioned housings and cooling solutions, as the quad-core versions have a thermal design power of 45 Watts. However, due to the high degree of scalability it offers for computing power, functionality and power consumption, the 2nd generation Intel® Core™ processor family is not only suitable for increasingly compact designs but can also be utilized across the entire range of embedded applications, right up to HPEC (high-performance embedded computing) with up to four mainstream cores.

Next generation Turbo Boost
As for applications that are particularly power-hungry, the new processors provide enhanced Intel® Turbo Boost technology. The Next Gen Turbo Boost mode not only increases the clock speeds of the processor cores, but also the graphics unit, independently of load, supply voltage and temperature. This automatically shifts processor cores and processor graphics resources to accelerate performance,
tailoring a workload to give users an immediate performance boost for their applications whenever needed. Depending on the load, the actual speed can be increased by up to 40%. Because the new turbo boost technology can overclock not only single, but also all cores, both older single-thread applications and modern multithread applications benefit from the computing turbo. Furthermore, the Power Manager now has the option of overclocking a core which was switched off for a given time for approximately 10 to 20 seconds immediately after waking up than would be the case if the core has been active for some time. Right after the core wakes up, the maximum application performance is available to reactivate inactive processes at high speed as needed. Thus, the thermal budget is more efficiently used. The integration of CPU and GPU on one die also results in additional flexibility. If the GPU is not being used, the power manager can assign parts of the thermal budget to the CPU. In the opposite case, the CPU cores can also be stepped down and the GPU units overclocked, so that graphics-intensive applications also benefit from an additional performance surge.

Enhanced Intel® Advanced Vector Extensions
Another innovation the processors offer is the new instruction set, known as Intel® Advanced Vector Extensions (AVX). Thanks to the doubling of the vector register size from 128 to 256 bits, AVX processors can accelerate the peak performance of floating-point applications and multimedia applications by a factor of two. The new instruction set accelerates floating-point intensive applications in high-performance embedded computing as well as the digital processing of images, videos and audio data in industrial automation, medical and military applications. These high-performance embedded applications also benefit from the processor’s support for OpenCL 1.1. OpenCL provides software developers with a uniform programming environment to write efficient, portable code for high-performance computing servers, reducing the development effort and time-to-market for data-parallel applications on multi-core architectures.

Processing and visualization of huge amounts of data
These new features make embedded platforms equipped with the 2nd generation of Intel® Core™ processors an ideal solution for applications in which a huge amount of data has to be processed in a limited thermal envelope. The first area to benefit from innovations, such as AVX and improved graphics performance, is situational awareness and applications such as radar, sonar, image processing, video surveillance with recognition and computer-aided diagnostics (CAD). Equipped with the new graphics core, embedded platforms can also control two displays independently of each other. Together with new digital display interfaces such as DisplayPort that allow cable lengths of up to thirty feet without having to use a repeater, it is possible to decentralize the display units, enabling a centralized computing architecture to be created that features several different human/machine interfaces. This is the second new application area, enabling industrial server applications to be utilized along with extremely thin clients that only need a keyboard, visual display unit and mouse (KVM) — which cuts installation and maintenance costs dramatically and improves maintainability as well.

The new benchmark for x86 devices comes in different flavors
Owing to this highly attractive feature set, the 2nd generation Intel® Core™ i3/i5/i7 processors are the ideal candidates to replace many existing platforms for new design-ins. To unleash the full potential of this technology and speed customers’ time-to-market, Kontron has implemented the innovative high-performance, low power-to-performance ratio on a broad array of suitable standard form factors with even more boards and systems to follow soon:

COM Express® basic Computer-on-Module
Based on the 2nd generation Intel® Core™ i7 processors, the new Kontron ETXexpress®-SC Computer-on-Modules are now the most powerful COM Express® modules available. Without exceeding the thermal boundaries of comparable forerunners, they offer more capacity, especially for applications that are graphics and computing intensive. Applications that are built around the Kontron ETXexpress®-SC will be able to utilize two high-quality HD video streams simultaneously, enabling economical multi-display solutions with one platform supporting several displays. This makes the new Computer-on-Module an ideal fit for feature-rich, graphics-oriented applications such as digital-signage servers running several displays, gaming systems and high-performance medical appliances.

Mini-ITX and Flex-ATX embedded motherboards
Built on the 2nd generation Intel® Core™ i3/i5/i7 processors, the Kontron Flex-ATX embedded motherboard KTQ67/Flex and the Kontron Mini-ITX embedded motherboard KTQM67/mITX are Kontron’s highest performing ATX-compliant embedded designs. With their extensive range of interfaces, the Kontron Mini-ITX and Flex-ATX embedded motherboards simplify the design-in process because they include all required standard interfaces for a broad range of computing-intensive and graphics-intensive applications, such as image processing in industrial automation, medical and military applications as well as digital signage, infotainment and gaming applications. Even multi-screen applications with simultaneous presentation of two separate HD videos or innovative 3-D BluRay applications are enabled with the Kontron KTQ67 embedded motherboards, without additional components.

6U CompactPCI® blade
Based on the 2nd generation Intel® Core™ i5/i7 mobile processor technology and designed to bring leading-edge performance, low power consumption and low heat dissipation to a broad range of applications, the Kontron CompactPCI® processor board CP6003-SA (Standard Air-Cooled) is an ideal fit for communications, military, aerospace, medical, industrial and monitoring systems. For maximum application flexibility the Kontron CP6003-SA comes with an extensive range of interfaces: 6x SATA ports with RAID 0/1/5/10 functionality for enhanced data security, 6x USB 2.0 ports, 2x RS232 ports, VGA, dual HDMI and High Definition Audio (HDA) interfaces as well as 5x Gigabit Ethernet interfaces connected via PCI Express to meet the high performance requirements of communications applications.

3U VPX CPU board
Integrating the Intel® Core™ i7 2655LE processor, the new Kontron 3U VPX CPU board VX3035 defines a new performance class for SWaP (size, weight and power) optimized high-performance embedded computing applications. OEMs will benefit from the Kontron 3U VPX CPU board VX3035 through the outstanding versatility and x86 technology, coupled with high vector and parallel computing power. System developers can develop extremely compact and light applications with high parallel computing power, such as video and image processing, radar, sonar or signal processing in software-defined wireless equipment. The new VPX board also supports established APIs such as Open CL, which simplifies and speeds up application development.

Application-ready platforms
Kontron offers extensive custom design services in addition to migration support that includes validation and verification. When taking advantage of these services, a hardware offering becomes an application-ready platform – regardless of whether it is a standard or semi-custom or full custom module, motherboard, IPC or system design. On request, they include all required hardware components and hardware-optimized software implementation for the respective target application and are ready for use with the customer’s application software. Upon request, they can be certified for the intended target market. So OEMs only have to integrate the application-ready platform in their application. That shortens time-to-market, lowers the total cost of ownership and is the foundation for high quality.
www.kontron.com

At the recent Embedded World event in Nuremberg, AMD’s Embedded Solutions division announced new processor technology for the embedded computing market: the AMD Embedded G-Series processors. Based on the same new 64-bit, CPU core that is part of the AMD Embedded G-Series Accelerated Processing Units (APUs), this technology delivers impressive x86 processing performance for deeply embedded, “headless” systems and devices which do not require any graphics output.

Historically, one of the main reasons for implementing x86 technologies into embedded systems was their high multi-purpose computing performance and network connectivity. As embedded computing technology has become more and more prevalent, sophisticated graphics capabilities for human machine interfaces (HMIs) in many different vertical markets have also dramatically gained significance. The combination of these two factors, the high multi-purpose computing power and the graphics capabilities, are paving the way for the extensive and growing success of x86 technology in embedded applications.
With the ongoing improvements in CPU performance, x86 processor technology has also proven successful and moved into areas where no graphics interface is required, such as high performance rack systems and backplane systems as used in AT/ISA 96 systems, VME or CompactPCI systems and ATCA, MicroTCA and VPX systems. Since graphics performance is not required, vendors have often implemented server-class chipsets into these systems.
In recent years, the low power embedded segment and dedicated-use systems have also been designed around x86 technology. This has been made possible by the ever increasing performance-per-watt ratio and dramatically reduced footprint of new embedded x86 platforms, which now easily fit into very small designs and can meet the typical physical constraints of deeply embedded devices. Thus, x86 processor technology is now in a position to move more and more deeply into applications and segments where other processor technologies have dominated in the past. x86 technology is now set up to benefit headless system designs which have no need for a graphics interface for displays.

Headless Applications for Small Form Factor Embedded Devices
One example is the industrial automation sector where in the past, conventional hardware-decoded programmable logic controllers (PLCs) in the process level dominated. These devices usually provide no direct graphics functionality for the user interface. They are often connected to sensors and actuators such as motion control or distributed conveyor sensors and many other industrial applications. In this area, x86-based soft PLCs can now deliver, together with the connectivity via the always-on grid of connected devices, a value that can best be described by the terms “openness” and “user comfort”.
The ability to access these deeply embedded devices via web browsers, for example, makes it possible to remotely configure and monitor decentralized processes over an entire factory from anywhere in the world.
When OEMs use an x86 technology platform for these devices, they benefit from the extensive x86 ecosystem of software, tools, and compilers.
There are further efficiencies based on the familiarity that so many designers and developers have with x86. System integrators can leverage unified and seamless communication and networking infrastructure across the entire shop floor up to the IT network, including the embedded systems in the field. Being able to deploy unified technology across the entire infrastructure can bring unique advantages in terms of cost and reliability.
These enhancements open the possibilities to move even more deeply down the stack to sensors and actuators.

Downsizing is the Key
Until now, this has been somewhat of a dilemma for x86 processor platforms: the smaller they became, the more functionality they integrated. This is especially true as the graphics unit, usually the second most energy-demanding component after the CPU, moved from the chipset into a single unit with the processor, enabling space-saving and highly power-efficient two chip solutions instead of the former triumvirate of CPU, northbridge, and southbridge. Yet, despite the high integration of functionalities into the processor and the small form factor trend spurred by this integration, x86 technologies have still often been viewed as “oversized” for deeply embedded headless applications. This perception has persisted, even considering the fact that the x86 platform can now be an ideal fit with its low power consumption, small form factor and proven technologies used in millions of standard consumer devices and the extremely wide ecosystem of software and development tools.
Consequently, to better pave the way for designers to take advantage of the benefits of x86 for deeply embedded applications, the ideal step would be to eliminate the overhead functionalities which are not required by excluding them from the processor's die. This is exactly what AMD has now done with its AMD Embedded G-Series processor. Following the recently launched AMD Embedded APUs in January 2011, at the Embedded World trade show AMD presented three new CPUs for the AMD Embedded G-Series, all based on the eagerly-awaited “Bobcat” core. These new CPUs are specifically offered for headless implementations, where there is no need for graphics or direct user input and these new variants of the AMD Embedded G-Series platform deliver amazing x86 CPU functionality.
As with the standard APUs, the headless system variants of the AMD Embedded G-Series feature exceptional power efficiency and a feature set that is optimized to the needs of a large range of embedded systems. With three performance classes from the 800 MHz single-core processor T24L up to the 1.4 GHz dual core T48L, the 64-bit multi-purpose x86 processing performance can be adjusted to suit the application. The CPUs feature a maximum thermal design power (TDP) of just 5 to 18 watts. Furthermore, these new CPUs also include a variety of critical system elements including memory controllers, I/O controllers and bus interfaces. All this processing power comes in a very small BGA package that enables fanless designs and 4-layer printed circuit boards.

A Scalable Platform for Nearly All Applications
With the new AMD Embedded G-Series CPUs, engineers can develop their embedded devices with new levels of power efficiency and can recognize more cost-effectiveness with optimized x86 platforms. Now, there is no need to change the basic technology platform that so many designers and engineers are familiar with in order to move more deeply into embedded appliances.
These benefits make the AMD Embedded G-Series platform – whether it’s the CPU or the APU - an ideal choice for a wide range of applications in the converging embedded markets. On the one hand, this new technology serves embedded applications in the consumer electronics (CE) area, smart residential gateways, storage appliances and NAS servers, and other network-connected devices. On the other hand, the highly scalable platform also serves deeply embedded applications which require exceptional overall performance on a small form factor and fanless design in combination with long-term availability. These designs can be found in many industrial markets such as automation, transportation, distributed smart grid data boxes, rugged firewalls, M2M and hundreds of other small boxes required for control applications or to collect and distribute data.
Plus, a further fact is convincing: because both the CPU and APU technology is based on the same AMD Embedded G-Series platform, hardware platform vendors can find it very easy to switch their designs between the APUs and the CPU. They are thus able to offer both advantages with only a slight redesign of their full custom designs or board-level products such as Computer-on-Modules, single board computers, and motherboards. Thus the broad ecosystem developed for standard low power x86 devices can also be extended for usage in even more specialized embedded devices.

Innovative Small Form Factor Designs
Owing to continuous improvements in processor design, the AMD Embedded G-Series platform has become more compact and power-optimized. The integration of the APU device reduces the footprint of a traditional three-chip platform to two chips. The APU and its companion controller hub simplify the design, as fewer board layers and a smaller power supply are required. With a 48% area efficiency improvement compared to the previous platform generations, the small footprint and low power consumption help reduce overall system costs and enable fan-less ultra-mobile devices to run longer between battery charges.

Minimized Product Life Cycle Costs
With an array of performance options, ranging from a 1.2 GHz single-core APU up to the 1.6 GHz dual-core variants, the AMD Embedded G-Series platform enables OEMs to utilize single board designs for the whole span of embedded systems - from entry-level up to high-end solutions.
Thus a single platform can be the basis for a host of product variants, for example a product family of box PCs with SKUs ranging from low-power up to high-performance versions. And if a new system based on this platform has already been developed, the reusability factor for new designs is tremendous because the processor’s high scalability covers the great majority of today’s x86 performance requirements in most embedded markets. Due to the common denominators of scalable platform design, the supply chain is simplified and operational complexity is minimized along with those associated costs, helping to drive better platform economics for the OEM. Furthermore the AMD Embedded lifecycles help to ensure the long-term availability of the platform which is essential, especially for the non-CE embedded computing markets.

Conclusion
Both the AMD Embedded G-Series APUs and the CPUs for headless designs provide embedded customers with a complete and scalable platform with long-term support. This helps to speed up design work and development cycles and therefore helps shorten the time-to-market for applications that can offer an outstanding performance-per-watt ratio. The ideal applications for this platform cover a broad range - they rely on impressive visual experience while maintaining very low power consumption or require an exceptional high parallel processing power or they are focused an optimized feature set and highly efficient CPU performance for deeply embedded systems. With all the benefits available on a extremely compact footprint, it is not surprising that parallel to the launch of the new AMD Embedded G-Series platform, several embedded hardware manufacturers, including Compulab, Congatec, Fujitsu and Kontron, have already announced products with the world’s first APU for embedded systems on a broad range of form factors that can be also easily switched to headless variants. This can be done far more easily compared to previous platforms, since all designs have the same controller hub. With the introduction of one of the most competitive technologies to date, AMD’s new APU technology is a compelling solution which is not only suitable for the majority of applications in the entire embedded market, but also, and excitingly so, has the potential to revolutionize the embedded computing market itself.
Thus, OEMs should consider evaluating this new technology in their endeavor to fulfill customers' demands for a vivid user experience and massive data throughputs in all offered performance classes.

Author:
Aurelius Wosylus, Regional Sales Manager Europe, AMD GmbH - Embedded Business Unit

www.amd.com

Every year, 20 million tonnes of lignite are excavated by the energy group Vattenfall using giant excavators. Robust computer technology delivers crucial information to ensure the excavators are operated as efficiently as possible and that coal performance is optimized. Vattenfall commissioned EWG automation GmbH to find an ideal hardware platform to renew the outdated diagnostic and visualization systems.
Kontron provided the fitting hardware solution.

The lignite open pit excavators in Welzow South in Eastern Germany have been in use for several decades. In the past, these were controlled manually. Today, more powerful diagnostic and visualization systems take care of increasing operational efficiency by monitoring, for example, specific flow rates and other key parameters. By applying the collected data, the excavator performance and the excavation angle can be adapted to the hardness and geological composition of the coal and so-called intermediate means (fault in the coal seam). Additionally, data regarding the motor currents and strains and the flow rates are sent from the measuring system directly over Ethernet connections to the operator’s workstation. Information on the specific coal performance is transferred to the mine control room and is also relevant for the surrounding power plants.
Continual improvements in the methods used to optimize operation logically mean that increasing demands are made on hardware. The technology for diagnosis and visualization no longer met Vattenfall’s expectations and an overall update was required. First, the systems had reached capacity limits due to the many functional extensions that were made. Therefore, the new systems had to deliver a higher performance level. Second, due to the range of extensions that had been made, the hardware structure had become heterogeneous with system components from a number of different manufacturers. Therefore, the hardware structure needed to be standardized so that maintenance and any expansions would be easy to carry out in future investments. Furthermore, the systems had to become manufacturer-independent. Vattenfall contracted EWG automation GmbH to develop this new powerful and standardized hardware platform, which also had to meet the high quality standards required in open mining. EWG had proven its expertise in numerous projects in opening mining and had carried out installations with guidance and control technology, software and special equipment development.

One system platform for many different requirements
Identifying the ideal platform where both the diagnosis and the visualization system could operate was the challenge for EWG, considering the requirements for both systems are very different. For the visualization of the necessary information in the operator cabin, such as status/error messages of the motors, only relatively average performance is required for good graphics as well as moderate hard drive and memory capacity. Diagnosis systems are completely different. Processing the large amounts of data regarding diagnosis, analysis and optimization of the individual technical processes, and the provision of fast status graphics based on complex data source, require a high level of computing performance. And for the assessment of the statuses, the user must have access to long term trends, which in turn requires extensive database archives. Consequently, increased demands are made on hard drives and memory performance. EWG had to find a common system platform that would be flexible and modular and that would cater for both systems.

High IO flexibility required
IO flexibility was essential, even though in most cases, Ethernet is used to connect operating clients. In order to guarantee maximum flexibility to the field, the system needed to support other interfaces such as RS232 ports or industrial IOs and field buses.

Deploying different operating systems and applications
In terms of software, the systems had to be extremely versatile as well. The computer systems on excavators are run on different operating systems and these are not always the latest versions, depending on how long ago the installation took place. Application software solutions from different vendors are also used. Consequently, this software diversity requires an open system structure that is capable of supporting all operating systems in different versions. A software-flexible system would also ensure that the migration to newer operating systems would be more convenient. New operating systems can be implemented gradually and if needed, old applications can be kept running.

Long-term investment security
Studying these requirements and recognizing the extremely long life cycles of mining equipment, it becomes apparent that in the mining sector, investments in process automation systems are long-term and the systems have to remain in use for several years. Therefore, it is important that individual components can be exchanged on a modular basis so that if a defect occurs, or an upgrade is necessary, entirely new systems do not have to be purchased. Given the long operating time of the systems it is also of paramount importance that the components have long-term availability. That means that not only the right components have to be selected, but the embedded computer standard itself must be chosen accordingly.
Low-frequency vibrations and dust
The best components are those that never need to be replaced. For that reason, systems were chosen which operate reliably even under the demanding environmental conditions of open pit mining. Even though most of the computing technology is housed in cabinet systems in a protected and air-conditioned environment, the systems have to ensure a safe start in all operating situations and under all conditions. The components are also exposed to a high degree of pollution caused by small amounts of dust from the ventilation systems.
Furthermore, the computer systems have to withstand a great deal of mechanical stress including low-frequency vibrations in the drive components in the 5Hz range. Non-directional impacts and shock loads must also be taken into account. Given these pressures and the required availability, the systems therefore have to be designed in an extremely robust fashion.

System evaluation led to CompactPCI
With this criteria, EWG started the search for rugged, industrial PCs, based on recognized industry standards and featuring flexible modularity. On closer examination, a large number of systems immediately failed the test. Only the CompactPCI standard remained as a candidate because of its robust construction and the fact that it has a wide range of IOs owing to its strong presence in the market. Due to its compact design, the 3U CompactPCI form factor makes space-saving system architectures possible that can be easily built into tightly-spaced driving cabs or control rooms. Choosing the manufacturer was the last step. EWG decided on Kontron. This was due to their positive experience working together on projects in the past: “Kontron’s CompactPCI products have shown very good voltage stability and strength. The products have also proven to be very robust and have delivered fail-safe operation even when temperature fluctuations and condensation effects have occurred”, Carsten Wetzk, Project Leader at EWG, comments. The systems have already proven themselves under mining conditions.
Service is crucial
For EWG, a further important aspect played a major role. All components should come from one source and should be available as standard components. “Despite all the various possible options we had to choose from, more than anything we needed to find the right solution quickly,” EWG engineer Carsten Wetzk comments. “It was also particularly important to be able to obtain application-ready, pre-validated systems. That proves extremely practical and efficient. And it meant that we could focus completely on the integration of systems in the plant structure’s control system, which saved us a lot of time and ultimately saved the customer money.”

The system configuration
EWG’s configuration features a Kontron 3U CompactPCI rack system chassis. An integrated CompactPCI switching power supply and an external UPS take care of the non-fluctuating power supply and protect the equipment from damage by any voltages changes. The high performance 3U CompactPCI processor CP307 Intel ® Core(TM) 2 Duo processor with 2.16GHz, 667MHz front side bus and up to 4GByte of DDR2 SDRAM delivers the computing power needed for the measurement and visualization systems. In order to provide additional interfaces such as RS232 or PS/2, EWG opted for the expansion module CP307 CP307-EXT-IOID. Thanks to the soldered processor and soldered memory, the CP307 is equipped to withstand the continuous effects of shock and vibration which occur in mining environments. In particularly harsh conditions, hard drives are no longer implemented but SSD which has been tested jointly with Kontron and which has proven to be an especially good alternative.

Autor:
Sandra Korsinek is product manager for 3U CompactPCI at Kontron
sandra.korsinek@kontron.com
www.kontron.com

For environmental monitoring of agricultural areas, researchers at CTR Carinthian Tech Research AG have developed an imaging system with multi-spectral data analysis that is integrated into a UAV (Unmanned Aerial Vehicle). For data recording directly in a UAV, CTR required a shock- and vibration-proof embedded computing platform that must be especially light and compact for the use in drones.

UAV-based environmental monitoring with Kontron Embedded BOX PC as a data logger

For the optimization of crop yields, it is essential to carry out an analysis of soil and vegetation. These data must record, for example, the ground water status and nutrient content of the soil or pest infestation.
This must be as up-to-date and accurate as possible, in order to respond quickly and precisely. Small fields are mostly maintained through personal sighting and manual soil sampling. For larger agricultural areas, however, this is very time consuming and costly and also not very accurate, since only isolated samples can be drawn.
Thus, the greater the agricultural area, the greater the need to obtain these measurements more efficiently.

Environmental monitoring with multispectral imaging
An alternative for the data collection is the environmental monitoring from the air, for example, by aircraft or satellite. The advantage to this is that with the help of aerial photographs, large areas of land can be recorded and analyzed in a short time. This is especially effective if you combine the digital image recording with spectroscopy methods. With this you can determine, for example, how much energy a plant reflects or absorbs in the form of photons or electromagnetic waves. Green plants reflect, for example, relatively little red light (wavelength of about 600-700 nm) in the visible spectral range, but in the infrared range (wavelength of about 650-1100 nm) relatively much. In addition, the reflection in the so-called “near” infrared range (in the infrared range, this lies close to the portion of the light that is visible to the human eye) strongly correlates with the vitality of a plant. The healthier a plant is, the greater the degree of reflection in this spectral range. Compared to conventional aerial photography, in which one can recognize only forest, water, or open areas, multispectral image processing offers the opportunity to identify whether plants need water or nutrients, or whether they are being attacked by pests. Other application fields lie in geology (rock analysis) and in environmental monitoring (detection of oil pollution, hydrological studies, and risk management).
To perform such multispectral measurements, the light must be refracted through a prism into the required wavelengths and recorded by special camera systems. Such camera systems are used for example in satellites that continuously collect data worldwide, such as global climate change and the resulting changes in vegetation. However, these satellite data are difficult to access and are only rarely available to farmers for any particular desired date. Therefore, aircraft are also used for current image data acquisition, which is very costly, however, and for European farmers only worth the expense in the rarest cases, namely for very large agricultural land.
But a more cost-efficient and environmentally friendly solution provides the image data collection with the help of a drone - a small unmanned flying object, which is radio-controlled from the ground.

Five image channels in one fell swoop
For use on such a UAV, the researchers at CTR have now developed a new imaging system for multi-spectral data analysis for three image channels in the visible wavelength range (400-500nm, 500-590nm and 590-670nm) and two image channels in the near infrared range (670-850nm and 850-1000nm), which can record and automatically analyze them. The system was integrated into the UAV (Unmanned Aerial Vehicle), a CAMCOPTER® S-100 from Schiebel, and successfully tested in flight operations. The innovation of the new CTR system is such that, in contrast to previous hyperspectral image acquisition methods, for the first time a multi-channel camera system by Quest Innovations is used.
The advantage of this camera design is that all five image channels are recorded simultaneously and capture exactly the same image, so that the post-synchronization of the five image channels is no longer necessary, eliminating the need for enormous computing capacity and complex algorithms, and thus saving costs. This is made possible by the use of common optics for all five CCD sensors. The camera resolves to 1280 × 1024 pixels per sensor, giving a particularly high spatial resolution at an altitude of 150 meters of 10 square centimeters per pixel (for comparison, airborne systems offer a spatial resolution of between 2.5 to 10 meters depending on the altitude). The frame rate of the camera is 30 frames per sensor per second, which with five CCD sensors, corresponds to a data rate of more than 210 MB per second. In operation, only one employee is needed to control the drone from the ground.

High requirements for the hardware
For reliable recording of the high data volume during the flight, CTR required a suitable embedded computer system that could be integrated directly into the drone. “For use in the drone we needed PC hardware which must be powerful enough to handle the data stream of more than 210MB per second without problems. Second, for use in the sometimes harsh environment inside the drone, it must also be particularly robust and shock-resistant. For use in a UAV with a limited payload, the hardware should also be as compact and lightweight as possible and easily accommodated in a sealed enclosure,” says Martin De Biasio, Project Manager at CTR. “In Kontron's product portfolio, thanks to the comprehensive advice regarding next systems, we very quickly found what we were looking for. Especially advantageous was the fact that our desired system was already available as an individually configurable standard product, eliminating the burden of adaptation and thus significantly reducing the time-to-market.”
In the end, CTR decided on the Kontron V-Box Express II, which was offered by next system Vertriebsges.m.b.H. as Exclusive VAER (Value Added Embedded Reseller) for Austria. This modular Embedded Box PC is extensible via both PCI and PCI Express standard cards and integrates as a processing core an ETX express Computer-on-Module. This conforms to the PICMG® specified COM Express® standard, which benefits CTR in long-term design security and scalable performance. Additio­nally, these Computer-on-Modu­les are available in various performance classes, which can be swapped out easily with each other. If more performance is required in the future, then it is sufficient to exchange the Computer-on-Module with a more powerful version with the latest processor technology. CTR obtains additional design security through the long-term availability of the Kontron system (up to 5 years), but also by the high system availability thanks to its high MTBF (Mean Time Between Failures) of more than 40,000 hours. In addition to the energy efficient fanless design, the system features shock and vibration resistance (IEC 60068-2-27 and IEC 60068), which Kontron ensured through extensive testing procedures in the development and production phase. Next system also provided the configurable system for CTR with a particularly robust SSD (Solid State Drive) as data storage medium. And thanks to the V Box Express II's available PCI-Express slots, the framegrabber card could also easily be integrated with the multi-channel camera system. CTR has also benefited from the compact size of the V Box Express II (235 × 330 × 130mm), for it allowed the computer to be easily attached to the drone, without negatively affecting its flight characteristics. Important in this context was also the high energy efficiency of the Box PC, which allowed it to be passively cooled and thus easily mounted in a sealed enclosure on the drone.

Authors:
Ingrid Hildebrandt is HMI Product Marketing Manager at Kontron
Martin Schiller is Kontron Product Manager at next system

www.nextsystem.at
www.ctr.at
www.kontron.com

Kontron Modular Computers GmbH
Sudetenstraße 7
87600 Kaufbeuren, Germany
Tel: +49 8341/803-428

Portable applications are constantly changing. Applications are gaining complexity with the intent to provide the end user with new experiences by adding new features. New features always provide new challenges for the power supply design. More power usually is needed although battery capacity and size limits it. Bigger displays with power-hungry backlights, more computing power, higher data storage capacities, built-in high performance cameras including flashlight function or extended wireless connectivity capabilities, are just a few examples. To keep or extend battery lifetime without increasing the size of the battery requires using low-power modes when the application blocks are not active.

By Juergen Neuhaeusler, Senior Systems Engineer – Advanced Low Power Solutions, Texas Instruments

KEY WORDS: peak-load, dynamic current limit, Lithium-Ion, Li-Ion, buck-boost converter, TPS62750, TPS63020, power management, analog, semiconductor, Texas Instruments, TI

These blocks immediately must switch to full power when needed to ensure the usability of the application is not affected. This can cause fast and big changes in the battery current. High peak currents with low duty cycles followed by almost zero current can occur. This reduces the average input current and, thus, extends battery lifetime – but it also means high and almost unpredictable peak loads at the battery.
Whether a battery configuration can handle this peak-load and how it will do it is defined by its output impedance, which differs from battery chemistries and battery connections. A possible battery switch, a protection circuit, if required, the battery connectors and the battery connection to the power management circuit together with the output impedance of the battery itself compose the source impedance of the voltage source for the application. Any high-peak current in the application will cause significant voltage drop across this output impedance and, thus, lower the real supply voltage of the power management circuit.
Figure 1 shows the measured output impedances of three different battery technologies. The magenta curve shows the output impedance of a dual cell alkaline in series configuration, the yellow curve shows the output impedance of a LiFePO secondary cell, and the blue curve for a Lithium-Ion (Li-Ion) secondary cell. The graph shows that both Lithium (Li)-based technologies are similar. The required protection circuit for the Li-Ion technology, which is not included in this measurement, increases the output impedance at least by the on resistance of the battery switches necessary to disconnect the cell. The alkaline cell configuration in this example suffers from the smaller cell size (AA compared to 18650) and the two cells in series configuration. The individual cell impedances are connected in series and the additional connection between the batteries is connected in series as well. In spite of this, the alkaline cells used in this test show a significant increase in output impedance during discharge compared to the almost constant value observed with the Li technologies.
When current is drawn from these batteries the voltage at the cells drops, as well as the input voltage of the connected power management circuit. It is caused by the voltage drop across all impedances of the battery and its connections. Due to the lower voltage the available power becomes lower. A connected DC/DC converter can compensate for this by increasing the input current since the demanded output power for the DC/DC converter is fixed and defined by the application circuit. At a certain battery current, increasing the battery current does not necessarily mean that the power drawn from the battery can be increased.
Figure 2 shows the result of a simple calculation assuming a constant source impedance of 350 mOhm, which is close to the worst case for the Li batteries shown above. The open circuit battery voltage range used for calculation is 1.8V to 4.5V. It can be seen that at higher battery voltages higher battery current still means higher battery output power. Increased power is not linear like it would be in the case of an ideal battery with 0 Ohm output impedance. But at low voltages the effect is reverse. At 1.8V, higher battery current results in less power available, if the current is higher than 2A.
If a certain power is needed, the battery cell configuration and the connections need to be analyzed in detail. It may be required to change the configuration towards multiple cells in parallel to better deal with the high currents, especially at almost discharged batteries. The voltage drop caused by peak input currents also affects the supply voltage range the power management system has to deal with. It is extended to lower voltages and requires different DC/DC converter topologies, like buck-boost converters.
Step-down converters are not able to regulate the output voltage when their supply voltage has dropped below their programmed output voltage caused by peak loads at the battery. This can result in unreliable operation of the system. Partial system shutdown triggered by undervoltage lockout detectors may occur as well as malfunctioning caused by supply voltage brownouts.
To solve these problems voltage monitoring circuits can be used to generate information for deciding to enable and disable different parts of the application, depending on available battery power. An example is not allowing the camera to flash in a mobile phone when the battery is almost discharged to ensure that mobile communication still works properly. To avoid wasting battery operation time, the available power must be predicted very accurately as well as the different use case scenarios and their worst case power demand. Higher power demand and lower power available over time due to aging effects as well as manufacturing variations must also be taken into account.
To avoid latching of the system due to overloading, the power source of the input current needs to be controlled properly. This can be done by using devices with an accurately controlled input current limit. Nice implementation examples are applications designed for working from USB power. The amount of current that can be drawn from a USB port is precisely defined. To control this properly, a power management circuit capable of working accurately at its current limit is required. The TPS62750 is an example of a step-down converter designed for this requirement.
If the power source is a battery, like the ones described above, the available power depends on the rate of discharge. If latching of the system should be avoided, the input current needs to be controlled as well. Unfortunately, since the possible maximum current depends on the battery’s rate of discharge, a constant input current limit may not satisfactorily solve the problem.
The required target value for the current limit is the lowest maximum battery current at worst case conditions. Since this occurs only at the end of discharge, this approach to a large extent significantly limits the available power at typical operating conditions.
This also limits the features that can be supported. Dynamically adjusting the input current limit according to the status of the battery allows keeping a full feature set alive at higher power available at typical operating conditions. It also helps to keep the system functional with a limited minimum feature set at extreme conditions. Getting an indication from the DC/DC converter that the currently available power is limited helps the system to decide to disable less important features in time. An example of a DC/DC converter supporting this design strategy in a simple way is the TPS 63020 buck-boost converter.
If the available input current is not sufficient to power the application, although the average current required is low enough, buffering the energy is required. This is usually done by using larger capacitors.
The peak current pulses are supported by the capacitor, which is charged up during the pauses between the pulses.
For that, smooth current limit operation of the DC/DC converter is required.
The DC/DC converter idles as soon as the output capacitor is charged to the nominal programmed voltage. The power consumption of the DC/DC converter in idle mode needs to be low, and the output impedance must be high to not discharge the output capacitor while waiting for the next load pulse.
For example, all of these features are implemented in the TPS 63020 buck-boost converter.

References
For more information about designing power supplies into portable equipment, download these datasheets: www.ti.com/tps62750-ca, and www.ti.com/tps63020-ca.

For more information about this and other power solutions from Texas Instruments, visit www.ti.com/power-ca

About the Author
Juergen Neuhaeusler is a systems engineer with the Advanced Low-Power Solutions group at TI.
Juergen is responsible for defining new power management devices, testing them and training customers to use them. Juergen received his diploma in electrical engi­neering from the Technical University in Munich.

Gabriela Petrache
TI - Customer Support Center
eecsc@ti.com

Developing a user interface is now one of the biggest challenges in embedded system design; do you choose an intuitive but conventional electro-mechanical interface, or a graphical interface which offers more flexibility but demands increased system resources? The decision is often driven less by need and more by desire; as a result designers must balance desire against functionality while maintaining control over production costs. This article provides some insight into the various user-interface options currently available, presenting examples of how these options can be used and providing some idea of the impact they have on system cost and processing.

Stephen Porter, Principle Applications Engineer, Home Appliance Solutions Group, Microchip Technology Inc.
Keith Curtis, Technical Staff Engineer, Security, Microcontroller and Technology Development Division, Microchip Technology Inc.

To emit, or not to emit
Display systems typically fall into a few broad categories, usually based on their basic technology, such as LED and LCD displays. These systems have both advantages and disadvantages, but overall they are generally capable of producing similar types of displays. The exact format of the displays varies, but the main categories are single indicators, segmented displays and graphics modules.
LED displays involve time-proven circuits that are microcontroller-friendly. In fact, most microcontrollers (MCUs) utilize general purpose input/output drivers with sufficient current capabilities to drive LEDs directly, with only a simple current-limiting resistor, because LED displays require only a few mA of drive. LEDs are also available in a wide variety of both individual indicators and segmented displays. However, due to their accumulated heat dissipation, they are generally precluded from larger graphic modules.
LCD displays utilize a liquid crystal fluid to either block or pass light through the display. Segmented and indicator LCD displays require low amounts of energy to switch the liquid crystal, making them MCU friendly, but they do rely on an external light source or a backlight to provide the necessary illumination, they also have a relatively limited temperature range.
Many small MCUs are capable of driving indicator and segmented displays with few external components, while some MCU manufacturers such as Microchip Technology provide complete graphic function libraries to assist in the development of graphic applications.
Figure 1 shows an example of a user interface that demonstrates several types of displays and user inputs.
This example makes use of the 16-bit PIC24F MCU to handle all of the inputs and outputs of this reference design.
Touch screens are an attractive alternative to electro-mechanical interfaces; the display’s entire surface is a user input, allowing the designer to redefine the user input on-the-fly by creating multiple, simpler interfaces.
On the other hand, electro-mechanical inputs involve switches, rotary encoders and potentiometers, and these items bring with them challenges such as mechanical wear and tear, mounting difficulties, and difficulties associated with sealing the interface against dust and moisture. However, mechanical technology is also used in resistive touch screens. Here, the user pushes two plastic layers together, creating an electrical connection that can be read using current drivers and Analog-to-Digital Converter (ADC) channels. Figure 2 shows a cross section of a resistive touch screen. This is a simple system, but it is subject to wear and tear, and it can require system calibration, filtering or linearization to compensate for physical variances. Mechanical contact systems rate high for ease of interface to an MCU, even though a simple algorithm to debounce the contacts is still a necessity.
Capacitive touch is another possible appliance user-interface option. This technology takes advantage of the basic construction of a capacitor—namely, two conductors separated by an insulator. When this field is applied to the iron in our blood, the system capacitively couples every surface of our body; from the tips of our fingers to the soles of our feet. Capacitive touch works by measuring the capacitance change caused by a finger touching the cover over a conductive plate. This increase in capacitance is measured and compared against the unpressed capacitance of the plate. Figure 3 shows the model for capacitive touch. If a sufficient shift in capacitance occurs, then the sensor is considered touched and the corresponding functions are activated. The primary requirements for the system are a sensor plate, an insulating covering such as glass or plastic and some means of measuring the capacitance with sufficient resolution. Several MCUs have built-in capacitive sense modules, such as some 8- and 16-bit PIC® MCUs.
For the ‘button and knobs’ format, it is simply a matter of creating the appropriate sensor pads, capacitance-measurement circuitry and the software to drive it. Some MCU manufacturers supply reference designs and supporting development tools to make this job easy. The only challenge is developing an appropriate averaging algorithm to determine the untouched capacitance of the sensor. Capacitive touch is also quite prevalent with touch screens, with two main forms currently available—surface-capacitive technology and projected capacitance.
Surface capacitive technology uses the finite resistance of an indium tin oxide layer on the back of the sensor. When the user touches the sensor, they form a capacitance to ground, which AC shorts the sensor at the point of the touch. The interface then determines the touch by measuring the current drawn by the sensor when each edge of the sensor is driven by an AC waveform. The relative currents are then used to calculate the distance from each edge to the user’s touch. Because the sense signal is in the MHz range, the design is often left to companies that specialize in the technology.
Projected capacitive touch works by creating two layers of touch sensors, one which is a series of horizontal stripes, and the second that is a series of vertical stripes. The interface electronics interrogate the system in order to determine which horizontal and vertical stripes are closest to the user’s press and interpolate a final position. Projected capacitive systems are generally simpler than their surface capacitive brethren, but they do have to scan many more inputs to detect a touch, which tends to increase system overhead and slows its response. Many of today’s kitchen appliances involve finishes that consist of metal, plastic and glass. Sometimes appliance designers use a combination of these, to provide the sleek look that today’s appliance consumers want. For example, stainless steel is a finish often seen on appliances. However, with stainless steel finishes, appliance manufacturers must still use stainless-steel looking plastic or even glass plates to implement the capacitive-touch control buttons. Technology and manufacturing costs can impact the overall feel of the products with this approach. How can appliance manufactures get around this? The answer is the final user-input technology that this article will discuss—inductive touch sensing. Inductive touch enables appliance designers to utilize metal such as stainless steel or aluminum as the main surface of the product, itself, for sensing deflections (see Figure 4 on the top). This is accomplished by mounting a specifically-designed circuit board behind the metal, where the buttons are to be placed. A thin spacer layer is used to create a small gap to enable the metal to be slightly deflected. The amount of deflection required is very small, as shown in Figure 5. The circuit board can also be the main control board for other functions, as processor requirements and usage are low for this technology.
In addition to providing an aesthetically-pleasing user interface, inductive touch-sensing technology works even when liquids are present. For example, the technology is not triggered by water or oil on the buttons and it will even operate under water. Microchip provides proprietary tech­nology that enables designers to quickly and easily implement inductive touch-sensing applications using PIC MCUs. The royalty-free technology can be downloaded from www.microchip.com/mtouch.
Inductive touch can also be implemented by inserting a small metal target layer behind a non-conductive fascia. The target layer changes the value of the inductor by mutual inductance, by causing the target layer to deflect when the front fascia deflects. The material for the target layer can be copper, aluminum or another material that is magnetically permeable or electrically conductive. The thickness of the target layer will depend upon the frequency used to drive the sensor. This provides the same end result as if only stainless steel was used. Because a metal target layer that is on one side of the board is measured, the back side of the PCB can be filled with copper to provide an EMC shield that helps with noise immunity and emission.

For more information, visit www.microchip.com/appliance and www.microchip.com/humaninterface
Please also visit the authors’ user-interface blog at http://notesfromthelab.com

Note: The Microchip name and logo, and PIC are registered trademarks of Microchip Technology Inc. in the U.S.A. and other countries. All other trademarks mentioned herein are property of their respective companies.

Farnell, the leading distributor of electronic and industrial components has announced it is now stocking International Rectifier’s Gen 2.1 SupIRBuck™ point-of-load (PoL) voltage regulators.
The new family of high efficiency products is offered with a range of input voltages from 1.5V to 16V and is ideal for providing power management solutions in a wide variety of applications where minimising power consumption is of importance. To assist in the adoption of SupIRBuck Gen 2.1 PoL voltage regulators, Farnell will also stock product evaluation kits that can simplify development and help customers shorten time-to-market for their new designs. Online design tools are hosted on both the International Rectifier website at mypower.irf.com/SupIRBuck/ and on Farnell’s online element14 technology portal and eCommunity, which provides further valuable support.
“With the drive to minimise power consumption in new product designs, high efficiency power management solutions have taken on new importance,” said Richard Curtin, Farnell's Segment Manager for Semiconductors Passives and Optoelectronics. “At the same time, simplifying the design process to shorten time-to-market giving OEMs a competitive edge is also crucial. With the products and support encompassed in this agreement with International Rectifier we hope to satisfy both of these needs comprehensively.”
“In addition to continuously improving and expanding the SupIRBuck product line in accordance and ahead of market trends and customer needs, we are committed to providing best-in-class design support to further establish SupIRBuck as the primary choice for performance, size and cost optimized power management designs for a broad range of embedded POL applications,” said Goran Stojcic, executive director, POL group, IR’s Enterprise Power Business Unit.
www.farnell.com