The World Leader in High Performance Signal Processing Solutions Robotics on the Blackfin Processor Dr. Fred Martin Assistant Professor, Computer Science University of Massachusetts Lowell

Presentation Overview History/Motivations for Educational Robot Controllers The Blackfin Handy Board: Hardware Design The Blackfin Handy Board: Software Environments Classroom Support Materials Demonstration

The Original Handy Board Developed for MIT LEGO Robot Competition, starting in 1991 Goal: Give students everything they need to start building robots Uses 2 MHz Motorola HC11 32K bytes of RAM 4 motor outputs 7 analog, 9 digital sensor inputs Built-in battery pack & LCD screen “Interactive C” language Open-source design Over 10,000 in use Helped shape a new product category: Educational/classroom mobile robot controllers

Design Category: Robot Controllers & CPUs Many options, with various levels of integration Original Handy Board, LEGO RCX, and XBC/Gameboy provide sensor/motor I/O Blackfin HB has powerful processor and significant robotics support integrated into one design Degree of Robotics Support -->

Design Goals for Blackfin Handy Board Highlight power and capabilities of the Blackfin DSP Vision Advanced software development Keep integrated, hand-held design of original HB Support wide range of sensor/motor I/O

The Blackfin Handy Board

Blackfin Handy Board: CPU and Memory 600 MHz ADI BF ’ MB SDRAM 256 MB NAND flash 1 MB boot flash

Blackfin Handy Board: Robot Sub-System FPGA Xilinx Spartan 3E series FPGA “Board Support Package” includes motor PWM, sensor sampling CMOS camera PPI pass-thru LCD driver end-user programmable

Blackfin Handy Board: Motor Output DC motor output 4 channels bi-directional control 1A, 12v per motor locked antiphase & sign-magnitude PWM back-EMF velocity sensing motor status LEDs Servo motor control 8 outputs 5A, +5v motor power supply

Blackfin Handy Board: Sensor Input three ADI 12-bit A/Ds with 8-1 mux, continuously sampling at 48 kHz 12 external analog inputs 10 digital inputs 8 digital outputs two i2c connectors integral 2-axis accelerometer

Blackfin Handy Board: PPI Camera Port Blackfin PPI port for CMOS cameras (e.g. Omnivision) FPGA pass-thru (or image processing)

Blackfin Handy Board: Integrated Power Sub-System Battery/Charge Built-in 12v (10 AA cell) 2000 mAh battery pack Smart-charge circuit (rapid, trickle, thermal cut-off) Charge and run simultaneously Battery level sensor to Blackfin Power Regulation 5A, +5v supply for servo motors & external devices 3.3v, 1.8v supplies for Blackfin & FPGA high-efficient switching regulators

Blackfin Handy Board: Communications Debug Agent Built-in USB 1.1 emulator JTAG connector for external emulator 10/100 BT Ethernet RS232 Serial

Blackfin Handy Board: Human I/O 16x4 LCD screen 2 buttons & 4 LEDs User knob DAC w/amp & speaker

Blackfin Handy Board: Software Environments ADI Visual DSP++ C/C++ IDDE High-performance C compiler VDK Kernel for threads LWIP TCP/IP stack gcc & uClinux Compile standalone apps with gcc Run uClinux kernel and compile apps that use kernel services uBoot monitor LabVIEW Embedded for ADI Blackfin

Academic Support Materials Freely available courseware based on use of LabVIEW Embedded being developed; expected January 2007 Robotic Explorations text (2001) will be updated based on new Blackfin Handy Board design

Recap: Stuff You Can Plug Directly into the Blackfin HB Sensors: Resistive devices (photocell, switch, thermistor) Voltage sources (IR transistors, IR distance sensors, any 0-5v source) Ultrasonic ranging sensors Modulated sensors (e.g., 40 kHz IR) i2c devices Audio sources Motors 4 smallish DC motors (12v, 1A) 8 servo motors Big DC motors using ESCs in servo outputs (Electronic Speed Controllers) Vision Omnivision camera modules

Demonstration Wall-following using infrared distance sensors Multithreaded control program with separate priorities for side-mounted and front-mounted sensors Using VDSP++ and the VDK kernel

void sideSensorThread_RunFunction(void **inPtr) { int side_et = 0; priority = 2; while (1) { side_et = analog(ETSIDE); // Get distance on LEFT if (side_et > 400) // Too Close to wall { clear_led(1); clear_led(2); clear_led(3); set_led(1); // Turn Away pivot_right(75, priority); } else if (side_et < 350) { clear_led(1); clear_led(2); clear_led(3); set_led(3); // Turn Toward pivot_left(75, priority); } else // On Line { clear_led(1); clear_led(2); clear_led(3); set_led(2); // Go Straight motor(2, 100, priority); motor(1, 100, priority); } Wall-Following Robot VDK Code Void frontSensorThread_RunFunction(void **inPtr) { int FL_et = 0; // Front Left ET int FR_et = 0; // Front Right ET unsigned int loopCount = 0; priority = 3; while (1) { FL_et = analog(ETFL); FR_et = analog(ETFR); // Detect Front Obstacle while ( (FL_et > 350) || (FR_et > 350) ) { set_led(4); // Left Obstacle if ( FL_et > FR_et + 50 ) {pivot_right(75, priority);} // Right Obstacle else if ( FR_et > FL_et + 50 ) { pivot_left(75, priority); } // Forward Obstacle else { motor(1, 0, priority); motor(2, 0, priority); } FL_et = analog(ETFL); FR_et = analog(ETFR); } clear_led(4); }

More Information Schematic design, PCB art, FPGA code, and Blackfin software libraries to be distributed with open-source license Blackfin Handy Boards publicly available Q See for latest and to sign up for mailing list See LabVIEW Embedded Vision Tracking demo here in the booth