Miniature solid-state inertial sensors are now in widespread use in passenger cars and SUVs with electronic stability control (ESC) being one of the primary high-volume applications. Tens of millions of gyros and accelerometers have been installed in vehicles since ESC first appeared in 1995. The primary ESC inertial sensors are a yaw sensor that measures vehicle turn rate and an accelerometer that measures side-to-side acceleration. The success of these sensors can beattributed to the use of extremely stable micromachined structures made from crystalline quartz and silicon with no moving parts and corresponding fatigue failure.
When compared to one time programmable (OTP) or read only memory (ROM) microcontrollers (MCUs), a flash memory-based MCU is distinguished by its ability to be reprogrammed. Many applications today need memory not only for storing the application program but also for storing data, which may need to be updated from time to time and must be retained in the application system, even after power off. For example, with a remote control, the user does not want to lose the preferred settings every time the battery is changed. External serial EEPROM can serve this purpose well, but adding another component to the system means higher system cost, a larger board footprint and degraded system reliability. An MCU with reprogrammable flash memory is a good choice for such an application, particularly if the application program needs a periodic upgrade to a newer version with enhanced features.
The Connect ME JumpStart development kit from Digi International includes a Comment ME module and development board. Software provides a 90-day evaluation version of Microsoft's Visual Studio 2005 Professional and the Microsoft .NET Micro Framework SDK plug-in for Visual Studio. This kit provides a quick and easy way to investigate .NET Micro Framework and its related tools and to build an embedded product that requires an Ethernet connection.
Liquid cooling provides a convenient way to remove heat from electronic components, boards, and systems. Its efficiency exceeds that of moving air, and liquid-cooling equipment does not require air channels throughout an enclosure. Some engineers may think of liquid cooling and picture leaking pipes and damaged electronics. Fortunately, liquid cooling has moved from the prove-it-to-me stage to routine use in high-end computers and military-and-aerospace equipment. So, just think of liquid cooling as a reliable and efficient way to move heat from one place to another. The removed heat can travel some distance to a radiator that dissipates the heat into outdoor air, municipal water, seawater or even another cooling system.
On a recent flight I talked with a software-engineering manager about the challenges of finding good embedded-system developers. She told me she has a team of 12 developers, but only three had proficiency with drivers, board-support packages, and boot-loaders. The other nine -- all good application developers -- lacked low-level coding experience. I asked if she had heard of the Microsoft .NET Micro Framework.
Editor’s note: It is with great pleasure that I welcome Alix Paultre to the cast of characters at ECN. I’m handing over this bit of print real estate to Alix this month — but it’s only a one-month rental. See you next month! Cheers…Aimee Kalnoskas, editor-in-chief
Engineers and system designers can exchange information around the world using instant messaging, Web browsers, and e-mail protocols based on Ethernet. The impact on our daily jobs is part of a larger trend described in the book The World Is Flat by Thomas Friedman. Friedman describes how broad Ethernet adoption, combined with open protocols and widely adopted platforms such as the World Wide Web, causes a dramatic shift in the global economy. In his words, the global economy is becoming “flat.” In addition to delivering data in the global economy, Ethernet is well suited for distributed test and industrial automation systems. New Ethernet standards have increased bandwidth from 10 Mb/s in 1983 to 1 Gb/s in 1998. It will take several years for the new 10GBASE-T standard (2006) to reach comparable price points with the currently deployed 1GBASE-T and 100BASE-T standards. With Ethernet, as well as PCI Express and USB, industrial automation and test systems can operate with higher performance at lower costs.
Evolving communications technologies require systems that can support many existing and emerging standards. By implementing communication functions in software, designers can build such “future-proof” communications, called software defined radios (SDRs). Software tools must let developers work at a high level of abstraction so they can port reusable code to other systems. But even though SDRs depend on software for their agility, they still require hardware in the form of switch fabrics, high-speed interconnects, and heterogeneous processor architectures that include FPGAs.
The Software Defined Radio Forum is an industry association that promotes the development and deployment of reconfigurable radio systems. The group includes 100 member organizations involved with commercial, defense and civilian communications. Members' activities include wireless services, network operations, public-safety communications, and hardware and software developments.
Many different standards for wireless communications equipment are in use today. Narrowband communication standards use stronger transmission in a small slice of bandwidth. Wideband standards use lower transmission power across a larger bandwidth. Each standard defines minimum performance characteristics for receivers, and includes specifications such as bandwidth, maximum signal level, and sensitivity. GSM is one narrowband example; the channel bandwidth is 200 kHz. A GSM receiver must have a minimum sensitivity of –104 dBm and be able to tolerate a –13 dBm signal at the antenna. In contrast, CDMA2000 is a wideband standard that uses a 1.25 MHz bandwidth. CDMA2000 receivers need to have a minimum sensitivity of –117 dBm/1.25 MHz and tolerate a maximum signal of –30 dBm at 900 kHz offset.1
"Cost still rules applications," said Ross Bannatyne, Marketing Director at Silicon Laboratories, a supplier of 8051-based MCUs. "If 8-bit MCUs solve problems, why use more expensive 32-bit chips?" Newer 8051 derivatives, for example, execute 100 MIPS and on-chip multiply-accumulate accelerators let them handle signal-processing tasks. According to Bannatyne, some engineers might not realize 32-bit MCUs can incur code penalties. "They might assume an algorithm that requires 16 KB in an 8-bit MCU also needs 16 KB in a 32-bit processor. Often the code takes more memory in the 32-bit processor, often much more."
“The frog was wrong” — that’s what I saw on a giant billboard when driving toward New York’s Lincoln Tunnel last year. It turned out to be a Toyota advertisement, with fine print stating, “It is easy to be ‘green’ when you drive the new such-and-such…” I didn’t think much of the car, but the slogan is terrific. That’s what we think here at ECN.
One of the most critical factors in designing handheld, portable electronics today is reducing overall system power consumption. With increased consumer expectations, portable devices require longer battery life and higher performance. Even power reductions on the order of 10 mW are crucial to portable system designers and manufacturers.
The industry’s conversion from leaded (eutectic) to lead-free has been slow. The industry perception prior to July 2006 was a virtual overnight switch to lead-free. However, today many OEMs still have a “don’t care, wait and see attitude” since they’re either RoHS-exempt at this time or don’t sell into Europe.
As a youngster I enjoyed wiring up circuits with knife switches, lamps, buzzers and large dry cells. While in high school I made frequent trips to surplus-electronics stores in New York City and ordered components from mail-order supply houses. My projects included a 4-bit binary adder -- built from switches and relays -- and a tic-tac-toe machine. I also built my share of kits from Knight, Eico and Heath. My friend Bill Kuhn designed and built relay-logic learning machines.