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ATV INSTRUMENTATION DISPLAY

ATV INSTRUMENTATION DISPLAY . System Design Ed Raezer Senior Project Western Washington University. Desired Functions. Speedometer 0-99 MPH 1 MPH Resolution Tachometer 0-12000 RPM 100 RPM Resolution Odometer 0-9999.9 Miles 0.1 Mile Resolution Clock 12 Hour Clock HH:MM:SS.

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ATV INSTRUMENTATION DISPLAY

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  1. ATV INSTRUMENTATIONDISPLAY System Design Ed Raezer Senior Project Western Washington University

  2. Desired Functions • Speedometer • 0-99 MPH • 1 MPH Resolution • Tachometer • 0-12000 RPM • 100 RPM Resolution • Odometer • 0-9999.9 Miles • 0.1 Mile Resolution • Clock • 12 Hour Clock • HH:MM:SS

  3. Designing “To Do” List • Hardware • Which MCU to use? • How to interface system with ATV? • What to use for user interface? • Software • Which software kernel to use? • What tasks are needed? • How much memory needed?

  4. MicroController Choice • Motorola MC9S12C32 • 32k Bytes EEPROM, 2K Bytes RAM • Estimated Memory Needed • 8k Bytes EEPROM, 1.5K Bytes RAM • 26 I/O Ports

  5. Interfacing with ATV for RPMs

  6. RPM Readings -1.7Vpk pulse generated every engine rotation. -Needed to be converted to a digital 0-5V square wave signal so the MCU could read it. RPM Sensing circuit

  7. Wheel Rotation • Magnetic Reed switch • Magnet mounted on brake rotor trips switch every rotation • Creates a 0-5V square wave

  8. User Interface • 2x16 LCD Display • Large Characters • W/ backlight • Shift Light • Green LED • Redline Light • Red LED • RPM LED Bargraph • 3 Pushbuttons

  9. Schematic

  10. Kernel Selection • Kernel Choice: MicroC/OS-II Real-time preemptive multitasking kernel with a 1 ms tick period • Configured for my program • Modify (os_cfg.h)

  11. Task Needed & Priorities 4- Start Task 5- Clock Task 6- U.I. Task 7- Button Monitor Task 8- RPM Task 9- Speed Task

  12. Start Task Description: -Initializations: LCD, Keys, OSTick -Intialize Port Directions and Initial Values -Creates Tasks -Priority #4 -Period: once (at startup)

  13. Clock Task Description: -Keeps time using a software clock -Runs timer for speed task -Updates time buffer -Period: 10 msec (Periodic)

  14. User Interface Task Description: -Reacts to button presses -Clock Setting -Activates LEDs -Changes Display Modes -Displays data on LCD Display

  15. RPM Task Description: -Retrieves pulse count from pulse accumulator every 600 msec and converts to RPMs -Updates RPM buffer. -Controls LED Bargraph -Period: 600 msec (periodic)

  16. ISR • Interrupt caused by input from wheel rotation sensor • Counter incremented every time wheel makes one rotation. • Period: Dependent on speed of ATV

  17. Speed Task Description: -Every 5 wheel rotations, speed is calculated using timer ran in the clock task. -Unless 3 secs. have elapsed, then speed is calculated using # of tire rotations in that 3 second period. -Updates odometer -Updates speed buffer

  18. Dataflow Diagram

  19. User Interface State Diagram

  20. Prototype

  21. Learning Process • Leave time for the unexpected • Teamwork

  22. Questions? • Thank You For Your Time

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