Third-party boards jump-start designs

When you start a design that incorporates a microcontroller or DSP chip, take a close look at development or evaluation boards from thirdparty suppliers. Often, their boards provide more capabilities than those available from the chip vendors.



Tom Baugh, president of SoftBaugh (www.softbaugh. com), started a company based on the Texas Instruments MSP430 microcontroller. “I needed more than TI’s basic demo board, which provides only a socket and an LED. So, I created a board that included a ‘430 chip, a power source, a serial port, and so on. And I designed my own programmer. If I had to make my own boards, I figured other people did, too.”Baugh’s company now offers a series of evaluation system (ES) boards that represent the top of its product line. These boards come with many I/O devices, provide easy access to I/O pins and can accommodate a variety of power sources. If a ‘430-chip includes LCD drivers, the corresponding board comes with an LCD. The company also sells boot loaders, debuggers and several programmers for production and development use.



TIME IS MONEY

“When engineers start a project, we ask about their application so we can help them choose a ‘430 chip,” said Baugh. “Then they can buy an ES board that gives them the most capable chip in a given ‘430 family. If they choose the MSP430F449 MCU, for example, they can use the ES449 board. They just need to buy a USB programmer.”



If engineers want to run a ‘430-based circuit from an AAA battery, they could spend weeks determining what ‘430 chip to use, how you wire it up and what RS-232C chip to use. But an ES board that sells for a few hundred dollars gives them the equivalent of about three months of design time and $15,000 worth of development effort, according to Baugh. And, buyers get all the “lessons learned” as soon as they receive the board.



SoftBaugh’s D-Series demo boards highlight a technology such as ZigBee (DZ1611) or an application such as energy monitoring (DE427). When engineers buy a DE427 board, for example, they get more than just a demonstration. The board shows them how to build an energy meter, and it supplies about 80 percent of the design that engineers need. They add the other 20 percent and have a product.



BOARD ALTERNATIVES SUPPORT THE DERIVATIVES For software development, Baugh recommends engineers start with the free IAR Kickstart software available from the TI Website. This software has a code-size limit, so SoftBaugh also resells the unlimited IAR embedded workbench tools from IAR Systems AB of Sweden.



Sometimes, a third party produces boards that a chip vendor resells. “Most likely when engineers buy a DSP development board from Texas Instruments, it is one of ours,” said Mike Strain, president of Spectrum Digital (www.spectrumdigital. com). Spectrum Digital has offered DSP development boards for TI’s DSP chips for about 15 years. The company started as a supplier of JTAG emulators, which it still uses to connect its DSP boards to a host PC.



“When a chip vendor introduces a new family of processors, the first device usually comes loaded with features,” explained Strain. “Later chips may offer fewer peripherals or less memory, and the chip vendor may not want to develop special development boards for them. We offer boards to engineers who plan to use those derivative chips.”



Some customers use Spectrum Digital’s eZdsp and DSP starter kit boards directly in their application. They buy the boards and use expansion headers to connect the DSP functions with the rest of their system. Thus, they avoid the need to develop proprietary DSP hardware.



TAKE THE JTAG EMULATOR WITH YOU

When engineers new to DSP chips move from a spectrum digital development board to their own prototype DSP board, they may need a bit of assistance, said Strain. “We suggest they implement a JTAG port on their prototype board so they can rely on the same JTAG emulator they used with our development board. They can copy one of the JTAG-port reference designs on our Website or on our boards. Then, they can run small utility programs that help ensure the JTAG port works properly. The JTAG interface is essential because it lets developers load and debug their code.”



If the engineers’ prototype board does not work properly, they can take the JTAG emulator and go back to the development board to assure themselves their software tools works. That means they have isolated the problems to their prototype hardware.



A JTAG port also helps engineers test their prototype board. “When you have a good clock signal and power, you can use the JTAG port to load the DSP chip’s internal memory with test code,” said Strain. That code — written using TI’s Code Composer Studio tools — would read and write patterns to and from external memory and exercise I/O ports.



“If their design uses different types of memory IC, we can help them change our board-support library to accommodate the new devices,” noted Strain. “But, we cannot support specific applications. Instead, we point developers to other TI third-party developers that can provide graphics, compression and other algorithms.”