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ARM-Based Evaluation Boards for Motion and Sensing Applications

Evaluation boards remain one of the best tools for design engineers that want to experiment with a new microcontroller (MCU) architecture and investigate specific applications such as robotics, wireless communications, and motion sensing and control. To that end, Texas Instruments (TI) and STMicroelectronics have both introduced ARM-based evaluation or demonstration boards that also integrate a variety of intriguing peripherals and capabilities.

These boards allow design teams the chance to work with the 32-bit ARM® Cortex™-M3 processor – a relative newcomer to the MCU scene. Until now, most designers have worked primarily with 8- and 16-bit MCUs. The TI product is optimized for robotics applications, and the STMicroelectronics (ST) design supports what the company calls 10 degrees of freedom (10-DOF) in inertial and environmental sensing applications.

The TI Stellaris Evalbot (Robotic Evaluation Platform) evaluation platform is a small working robot originally introduced in the fall of 2010 (see Figure 1). Recently, the company unveiled an updated Evalbot with an extended library of sample projects and the ability to use wireless capabilities to communicate with the robot.

Figure 1: TI’s newest Evalbot evaluation platform provides designers with a tool to explore robotics applications and use a wireless development platform to remotely control the robot.

An 80-MHz Stellaris LM3S9B92 MCU powers the robotic platform and integrates 256 Kbytes of flash memory and 96 Kbytes of SRAM. The MCU also includes Ethernet and CAN interfaces, along with a USB interface that can be used in host, device, and on-the-go modes.

The robotic platform comes preloaded with TI’s StellarisWare application that provides baseline robotic capabilities. The design includes TI motor-driver ICs along with two DC motors that drive and steer the robot. Optical sensors monitor wheel rotation with 45° resolution, and other sensors handle bump detection.

TI offers five versions of the development platform for five different software-development tool chains, including Keil RealView MDK-ARM, IAR Systems Embedded Workbench, CodeSourcery G++ GNU, Code Red Technologies Red Suite, and TI Code Composer Studio tools. The tools are generally only available during an evaluation period, or are limited in terms of the size of project (code size) that can be produced

Perhaps the most enticing element of the new Evalbot platform is wireless support. The platform includes a wireless expansion port that can be populated with the TI CC1101 Evaluation module. The module operates at 868 or 915 MHz and is compatible with the TI eZ430-Chronos sport watch, which also functions as a wireless development system. The Chronos system is based on the 16-bit TI MSP430 MCU and can be programmed to control the Evalbot over the wireless link.

10 degrees of freedom
The new ST iNEMO (iNErtial MOdule) board is intended to demonstrate the capabilities of a variety of ST sensor ICs and modules and the 32-bit STM32F103RE MCU. Like the TI product, the latest STEVAL-MKI062V2 is the second-generation of an evaluation module.


Figure 2: The STMicroelectronics iNEMO demonstration module is based on the STM32F103RE MCU and provides three-axis sensing of linear, angular, and magnetic motion along with sensing temperature and barometric pressure.

The 4 x 4-cm module includes accelerometers, gyroscopes, magnetometers, and temperature and barometric sensors that ST refers to as a 10-DOF sensing platform.

Five separate sensing elements comprise the 10-DOF platform. The LPR430AL device is a MEMS-based, two-axis gyroscope that provides pitch and roll outputs. The LY330ALH device is a MEMS-based, yaw-axis gyroscope. The LSM303DLH device is a six-axis geomagnetic module. The LPS001DL is a pressure sensor. And the STLM75 is a temperature sensor.

Collectively, the 10-DOF platform provides three-axis sensing of linear, angular, and magnetic motion along with the capability of measuring temperature and pressure, the latter of which can be converted to altitude data. ST supplies PC software that allows developers to easily access the sensor data and a software library for use in the development process. The company suggests that the module will support robotic, virtual reality, augmented reality, and human machine interface applications.

The iNEMO module features a processor with 512 Kbytes of flash memory along with USB, CAN, 11 timers, and three A/D converters.

Hotenda also offers additional resources for design teams working on ARM-based projects. For example, the ARM Cortex Resource Guide includes a comprehensive set of articles on the Cortex family in addition to material specific to applications such as home automation and mobile devices.