You’ll find microcontroller development kits come in many sizes and with a variety of capabilities; from simple kits that address one type of application to complex development boards that offer a cornucopia of I/O devices. To see what companies now offer as ways to start using microcontrollers, we took a close look at four kits, two of which focus on motor control (Silicon Laboratories and Microchip) and two of which serve as general-purpose microcontroller development kits (Freescale and Ramtron). Our short reviews tell you what we liked and didn’t like about these kits and the ways in which they can assist you with an application or project.
Stepper Motor Reference Design Kit ($119) Silicon Laboratories
THE PRODUCT: The board in this kit comes with an 8051 microcontroller in place and four driver circuits ready to attach to a unipolar stepper motor (included). A JTAG programming pod makes the connection between a host computer’s USB port and the board. The board also provides a standard RS-232C serial port for computer-to-board communication. A power cube comes with a universal set of wall plugs. The CD-ROM contains documentation and Silicon Lab’s program-development software that operates through an IDE and lets you write code in the C language.
WHAT WE LIKED: This reference design provides everything you need to understand how to run a stepper motor under software control. A color-coded guide makes setup fool proof. Documents supply a solid explanation of stepper-motor operation and control, a schematic diagram and detailed descriptions of the hardware the reference design employs. Software listings include clear descriptions of operations and flow charts. Well commented code helps you understand the motor-control operations. A test program lets you control the stepper through the HyperTerminal program in Windows. Silicon Labs’ IDE was a breeze to install and use.
WHAT WE DIDN’T LIKE: Nothing stands out as a problem or shortcoming in this package. One minor nit to pick: The demo program’s command instructions are clear, but the explanation of rotations and position counts doesn’t thoroughly explain how to keep track of position. In short, position counts accumulate, regardless of the number of rotations. After a couple of sample runs, you figure it out.
LAST WORD: An excellent reference design that delivers on its promise. I wished I had more time to experiment with this kit, plow through the code, and modify it so the motor would step through my preset patterns. You can learn much from the software and documentation. Before you modify any code, though, read the AN155 document so you understand how the software accelerates and decelerates the motor and how it uses a table of values — provided in the code — for proper motor control.
More Info on Silicon Laboratories
VersaKit 3074 VRS51L3074 (8051 architecture microcontroller) ($99) Ramtron
THE PRODUCT: In mid 2006, Ramtron, formerly Goal Semiconductor, brought to market an 8051-based microcontroller, the VRS51L3074. The chip provides an enhanced 8051 processor core, peripherals, SRAM, and Flash memory as well as 8 kbytes of FRAM, or ferroelectric random access memory. The latter memory uses a magnetic structure to store information. Developers can use the VersaKit 3074 board to investigate the MCU chip and the use of FRAM memory. Programming takes place through a JTAG pod.
WHAT WE LIKED: The small board (3.5 × 3.75 in.) offers a lot of flexibility to hardware designers because it doesn’t include on-board peripherals that could reduce the available number of I/O signals. Even the eight LEDs come unconnected to any I/O lines. So, developers have access to all the MCU’s signals and they can exercise all of the chip’s internal peripherals. The board also includes a small breadboard area.
WHAT WE DIDN’T LIKE: The JTAG programming pod connects to a host PC through a parallel-port cable, which seems like a dated approach. These days development tools use either a serial port or a USB port. My laser printer uses a parallel port and I need to print program listings when I develop and debug code. The setup of supplied software requires too much work. You must load two freeware programs, the Small Device C Compiler (SDCC) and the Syn text editor. Then you must “connect” them to work together. The SDCC is a command-line compiler.
LAST WORD: This kit might have a lot going for it if the JTAG pod used a USB connection to communicate with a host PC, and if the company provided tutorial materials or even a few lessons on using the SDCC and Syn tools. Developers who must have an 8051 processor might have the fortitude to slog through the setup. I did not.
Expanded Review by Jon Titus | More Info on Ramtron |
Microchip Mechatronics Demo Board ($150) Microchip
THE PRODUCT: This demo board provides two motors — a brushed dc motor and a stepper motor — already mounted and ready to connect. And the board includes potentiometers, push buttons, LEDs, an LCD, a temperature sensor and a light sensor. The processor, a 40-pin Microchip PIC 16F917, came preprogrammed with a motor-control demonstration program. The MCU makes 14 I/O lines available for experimentation.
WHAT WE LIKED: In spite of a few documentation errors, it took little time to set up the board and run an experiment with the brushed dc motor. Two other experiments use a temperature sensor or a light sensor to control the motor’s speed. The board has a lot to offer and the standard header pins make it easy to connect jumpers to signals of interest. Although you can run the board from a 9-V battery, I recommend you use a lab power supply or “wall wart” power cube. The MPLAB IDE software works nicely for program development.
WHAT WE DIDN’T LIKE: Although the User’s Guide lists eight other “projects,” you must gather documentation from app notes and data sheets on the CD-ROM to proceed. The projects lack step-by-step instructions, so you’re on your own most of the way. To program the 16F917 microcontroller chip, you will need either a PICkit 2 Microcontroller Programmer ($50) or an MPLAB ICD 2 In-Circuit Debugger Programmer ($160). It took a lot of work and caused frustration to get the software configured for the PICkit 2 programmer.
LAST WORD: Microchip should include a check list that explains how to load software, gather updates, and install and start updated software. The company has put together a powerful mechatronics demonstration board, but the documentation and project instructions present a mishmash of information that will defy all but the most resolute developer. It’s sad to see the motors and interesting peripherals go to waste for the lack of clear step-by-step instructions.
Expanded Review by Jon Titus | More Info on Microchip |
DEMO9S08QG8 Demonstration Board for 8-bit Microcontrollers ($50) Freescale Semiconductor
THE PRODUCT: Freescale’s board came with a socketed 16-pin MC9S08QG8 processor from the company’s popular line of HC(S)08 microcontrollers. A female connector provides access to the chip’s 14 I/O signals — six on Port A and eight on Part B. Peripherals include an analog-to-digital converter (ADC), an analog comparator, several types of serial-communication devices, timers, and pulse-width modulators. You cannot use all peripherals simultaneously. Memory gives you 8 kbytes of Flash and 512 bytes of RAM. The package includes CodeWarrior development software, a CD-ROM with documentation, a USB cable, and a 16-page booklet.
WHAT WE LIKED: The board provided easy access to the MCU’s I/O pins, and a standard I/O header makes this board easy to use in a prototype. The USB connection for program downloads and debugging, and the availability of a processor socket lets developers produce small quantities of parts for prototypes. Users can disconnect pushbuttons, LEDs, light sensor and potentiometer to gain access to their I/O pins. Powered via USB port. Good response to technical questions about board software and solid CodeWarrior tools.
WHAT WE DIDN’T LIKE: Documentation and CD-ROM organization needs work as do software setup instructions, which seem to conflict with one another. Some demonstrations required a separate serial port that my laptop lacks, and instructions lack clarity and will confuse users. No tutorial or step-by-step information to help users work through a few examples. Difficult to locate header files. Peripheral and I/O port definitions require printing 69 pages. Digging into software requires solid C experience.
LAST WORD: I hate having to pry details out of multiple poorly organized documents. With a bit more thought and new educational material, this board might provide a useful introduction to an 8-bit MCU. As it stands, save your $50.
Expanded Review by Jon Titus | More Info on Freescale |