Texas Instruments: Stellaris®︎ Robotic Evaluation Board (Evalbot) with Micrium´s µC/OS-III

Kit Overview

The Stellaris Robotic Evaluation Board (EVALBOT) is a is a mini robot that allows developers to experience the Stellaris ARM Cortex-M3 based LM3S9B92 MCU in real-world applications that leverage the processor's integrated 10/100 Ethernet MAC/PHY, USB On-The-Go, CAN, and motion control capabilities. Based on a complete analog and embedded processing signal chain from TI, the kit includes all of the hardware and software required for quick assembly so that developers can begin evaluation in 10 minutes or less. The board also uses a range of Texas Instruments’ analog components for motor drive, power supply, and communications functions. After a few minutes of assembly, the EVALBOT’s electronics are ready-to-run.

When roaming, three AA batteries supply power to the EVALBOT. The EVALBOT automatically selects USB power when tethered to a PC as a USB device or when debugging. Test points are provided to all key EVALBOT signals. Two 20-pin headers enable future wireless communications using standardized Texas Instruments’ low-power embedded radio modules (EM boards). Additional microcontroller signals are available on break-out pads arranged in rows adjacent to the microcontroller.

The EVALBOT has factory-installed quickstart software resident in on-chip Flash memory. For software debugging and Flash programming, an integrated In-Circuit Debug Interface (ICDI) requires only a single USB cable for debug and serial port functions.

The EVALBOT is available in a bundle (EKB-UCOS3-BNDLEKB-UCOS3-BNDL) with a Stellaris-specific version of uC/OS-IIIuC/OS-III: The Real-Time Kernel by Jean J. Labrosse. This book reveals how a real-time kernel works using Micrium’s μC/OS-III and the Stellaris EVALBOT as references. In addition, the board is also available separately (EKB-UCOS3-EVMEKB-UCOS3-EVM) for those who already have the book.

The example projects include:

• Display : display various strings on the OLED display on a rotational basis to get familiarized with the basic structure of uC/OS-III operating on the EVM-EVALBOT
• Audio: play WAV files stored in the internal flash memory of the LM3S9B92 microcontroller
• Control: how to control each motor independently using the user buttons; turning motors off if the bump sensor is triggered; and monitoring robot status such as motor state, bump sensor state, CPU usage, and motor speed though uC/Probe.

LM3S9B92 Microcontroller

The Stellaris LM3S9B92 is an ARM Cortex-M3-based microcontroller with 256-KB flash memory, 96-KB SRAM, 80-MHz operation, Ethernet MAC/PHY, USB Host/Device/OTG, and a wide range of other peripherals. Unused microcontroller signals are routed to either the 20-pin EM expansion headers or to 0.1“ pitch break-out pads which are labeled with their GPIO reference. An internal multiplexer allows different peripheral functions to be assigned to each of these GPIO pads. When adding external circuitry, consideration should be given to the additional load on the EVALBOT’s power rails.

• Clocking
  The EVALBOT uses a 16.0-MHz crystal (Y3) to complete the LM3S9B92 microcontroller's main internal clock circuit. An internal PLL, configured in software, multiples this clock to higher frequencies for core and peripheral timing. A 25.0 MHz (Y1) crystal provides an accurate timebase for the Ethernet PHY.
• Power Supplies
  The EVALBOT can be powered either from batteries, the ICDI USB cable, or a USB device cable. The power source is determined by a Texas Instruments TPS2113 Auto Switching Power Mux and two Schottky diodes. Battery power is selected automatically when USB power is not present.

Key Applications: Motion control, Factory automation, Fire and security, HVAC and building control, Power and energy, Transportation, Test and measurement equipment, Medical instrumentation, Remote monitoring, Electronic point-of-sale (POS) machines, Network appliances and switches, Gaming equipment.