greentechZONE Products for the week of September 24, 2007
Texas Instruments Says…
Wireless MCU System-On-A-Stick Makes Development Faster and Easier
Flexible, $49 tool provides a MSP430 target processor with radio, debug hardware and development software
Making development even easier for low-power wireless systems, Texas Instruments Incorporated announced a new tool for designing embedded systems that combines ultra-low-power MSP430 microcontrollers (MCU) with wireless communications. At the low cost of $49, TI's new eZ430-RF2500 development tool, packaged in a convenient USB stick form factor, offers two radio frequency (RF)-enabled microcontroller target boards and a PC debugging interface that may be used to develop stand-alone wireless projects. Developers will now find it easier than ever to build low-power wireless systems for sensing and metering, home security and automation, medical and other innovative applications.
The eZ430-RF2500 builds on the success of TI's eZ430-F2013 development tool, introduced in early 2006. The eZ430-RF2500 opens up new possibilities for low-power designs combined with wireless communications. Backwards-compatible with the F20xx target boards, which have been sold separately since late 2006, the eZ430-RF2500 provides continuity for enhancing existing designs.
"Recognizing the strong demand for the eZ430-F2013 and the versatility of the target boards used to develop customer end products, we understand that a low cost tool with wireless capabilities is the next 'must have' for developers," said Cornelia Huellstrunk, product marketing manager, MSP430, Texas Instruments. "With the eZ430-RF2500, we are committed to meeting market needs, as more applications require wireless communications."
A complete, affordable solution for easy wireless MCU development
The eZ430-RF2500 development tool provides all the hardware and software needed to program the MSP430 MCU and the Low-Power RF 2.4-GHz transceiver on the postage stamp-sized target board. The new eZ430-RF2500 tool provides a complete solution for writing code as well as operating and testing the application in the field.
The USB stick development interface plugs into a PC port with no additional driver software, and then connects directly to an MCU-RF target board - the eZ430-RF2500T. Two target boards are included in the eZ430-RF2500 kit, providing the developer with the essentials of a wireless network. A battery pack (AAA), also included in the kit, enables a target board to operate as a stand-alone system, and standard through-hole pin connectors make it easy for external components or existing systems to attach to the target board. Features of the target board include two programmable LEDs to display activity, a programmable toggle button for interface and an integrated zero-power brownout detector that resets the MSP430 when power drops.
An MSP430F2274 MCU and a CC2500 RF transceiver, both from TI, are integrated in the eZ430-RF2500T target board. The MSP430F2274 MCU, based on a 16-bit RISC architecture, can handle generous amounts of code and data with its 32 Kbytes of flash memory and 1 Kbyte of RAM. The MSP430F2274 also features high performance, integrated analog such as a 12-channel 10-bit analog-to-digital converter (ADC) that samples at up to 200 kilosamples per second. Other on-chip peripherals include two operational amplifiers and support for UART, SPI, I2C and IrDA communications. The MCU offers five low-power modes for maximum power efficiency and features an ultra-fast wake-up from standby mode in less than one microsecond. The CC2500 is a highly-integrated multichannel RF transceiver designed for low-power wireless applications in the 2.4 GHz Industrial Scientific Medical (ISM) band. It has an automated packet engine and supports data rates from 1.2 to 500 kbps.
The eZ430-RF2500 kit comes with all the software needed to program wireless MSP430 applications, and the USB development interface provides the required hardware for emulation and debugging on the target board. The user can choose either the IAR Embedded Workbench IDE or TI's Code Composer Studio Essentials IDE to write and download code, then debug the application at full speed using hardware breakpoints and single stepping, consuming no extra hardware resources. The kit's software includes a protocol stack for low-power RF networks and hardware abstraction layers (HAL) enabling the rapid design and prototyping of wireless systems. In addition, the kit includes a complete example project, measuring temperature and voltage through a wireless sensor network. Full documentation for the tool and software is also included.
EN-Genius Says…
I’m reviewing this TI new development system in green-techZONE here because the wireless control networks made possible by products like the TI MSP430 are some of the green engineer’s most useful tools for adding the intelligence that buildings, industrial processes and other resource-intensive systems need in order to run at maximum efficiency and produce a minimum of waste. The development kit featured here is an enhanced version of the eZ430-F2013 System-on-a-Stick that created a minor revolution in the embedded world last year by putting a complete development platform for the MSP430 MCU in a USB thumb drive form factor at a retail cost of $20. The addition of a sub-$2 wireless link (thanks to the Chipcon group TI acquired a while back) gives you all the ingredients you’ll need to build a small wireless monitoring and control systems, including the sorts of energy management and conservation applications.
 This updated platform adds wireless data capabilities, a way to power the target processor when it’s unplugged from your host computer, and fixes some of the less-than-user-friendly features of the first version. Besides the radio subsystem, the thing I appreciate most about this new platform is the attention TI has paid to making it much easier to use than their first version. Several people I know who actually tried to use the earlier version really liked the fact that you could hang off their laptop USB ports and do meaningful development work but they were surprised at the level of skill TI expected you to have in order to use it. For example, there were a few tricky steps required to properly install the drivers required to push data back and forth the between emulator and debugger. The new system smoothes that speed bump with HID drivers so that it works in a plug-and-play manner similar to any consumer USB peripheral like a mouse or web camera.
The target system now has both an SPI-Bi-Wire and UART interface (see Fig. 1a above). Using the UART connection is particularly handy when you want to read or load the target system without having to fire up the development software. This makes it easy to create a PC-based application that reads or writes data or otherwise commands you target system. The outboard battery module makes it quick and easy to turn the target board into a stand-alone prototype system (see Fig. 1b ).
 The release above does a nice job of pointing out most of the features of the 2.4 GHz radio chip so I’ll only spend a little time going over a few details that might not be clear. It has an integrated PA that delivers 0 dBm to the antenna, a healthy signal level that makes the TI claim of a 300 ft open-air range seem credible. But even a technical giant like TI can’t defy the laws of physics so the data rate it can support varies widely according to range and environment. Depending on these variables, and how long you want your batteries to last, you can adjust the system data rate between 1.2 kbit/s and 500 kbit/s. This is more than enough speed for any smart lighting, energy management, or HAVC control system I can imagine, with lots of bandwidth left over to carry other traffic such as intrusion and fire sensors for security and safety functions.
As I mentioned earlier, the chipset uses TI’s own open-source wireless MAC and protocol stack (announced September 12, 2007). At 7 k for the entire stack, it has a much smaller code and memory footprint than ZigBee and is lighter on processor resources as well. TI makes no bones about the fact that you do have to trade off features and flexibility in exchange for the simpler code, but says that the 100-node maximum network size is more than adequate for nearly any residential application and many commercial/industrial ones as well. My only real disappointment is that they also had to forego support for a mesh network topology to conserve memory and processing power. While I think the point-to-point and star topologies it does support will be adequate for most situations, there are times when the flexibility that a meshed network enables is invaluable. Nevertheless, its simplicity and low cost may make it a better choice for many smart lighting and power management applications targeted at the residential and small business market.
In addition to giving you a ridiculously cheap platform to explore the possibilities of the MSP430 and its companion radio chip, TI tosses in over 200 pre-packaged code example modules (available both as C or assembler) that let you build the system of your dreams quickly. Besides the green power applications in smart buildings/building automation I mentioned, it should find lots of use in low-data rate sensor networks, environmental monitoring, and small industrial networks where the 100-node limit is not a problem. TI also sees big uses in medical and industrial markets for inventory tracking and patient tracking systems that deliver more intelligence than simple RFID technology can deliver.
About the only other knock I have for this smart little system is that it operates in the 2.4 GHz ISM band where noise floors are high and ranges are limited. When I asked about the possibility of a 900 MHz variant, TI declined to go on record with a definitive answer but I have heard reliable rumors that they are planning on releasing a pin-compatible 900 MHz band radio in early 2008. If you need the range and penetration that 900 MHz provides right now (and can deal with an 8051-based processor architecture), you can check out TI’s single-chip CC1110 they announced in the middle of September 2007. The 8051 does not have the processing power that the MSP430 does but it could probably be subverted to perform at least some energy management tasks instead of the alarm and security, automatic meter reading, industrial monitoring and control, and simple building automation tasks it was originally designed for.
But if you did go with the CC1110, you’d miss the opportunity to work with one of the cutest development systems I’ve ever seen.
The eZ430-RF2500 and eZ430-RF2500T will be available in October 2007. Pricing per unit will be $49 for the former. 1000-piece pricing for the chipset, including radio, will be around $5.
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