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LED CUBE

LED CUBE. Preliminary System Software Design Fernando J. Garcia May 16 2013. Microcontroller. MC9S12DP512 Bus frequency of 24MHz Memory Requirements ROM ~13K bytes RAM 4K bytes. Kernel. MicroC/OS-II Real-time preemptive multitasking kernel Priority Based 1 ms tick period 1 ISRs

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LED CUBE

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  1. LED CUBE Preliminary System Software Design Fernando J. Garcia May 16 2013

  2. Microcontroller MC9S12DP512 • Bus frequency of 24MHz • Memory Requirements • ROM ~13K bytes • RAM 4K bytes

  3. Kernel MicroC/OS-II • Real-time preemptive multitasking kernel • Priority Based • 1 ms tick period • 1 ISRs • Intertask communication • Mutexes • Semaphores

  4. Tasks and Priorities

  5. Start Task Description: • Initializes the system • Creates other tasks • Pulses cube lights • Priority #4 • Period: Once (startup) • Execution time ~2s

  6. PWM Task Description: • Resets timer required by LED drivers for PWM • Interrupt based • Priority #5 • Period: 166μs • Execution time(max): 1.6μs • CPU Load: 0.9%

  7. Transmit Task Description: • Transmit data over SPI (Serial Peripheral Interface) • Priority #6 • Period Sporadic 16ms • Execution time(max): 98μs • CPU Load: 0.6125%

  8. Key Task Description: • Periodically Scans keypad • Priority #7 • Period: 10ms • Execution time(max): 10μs • CPU Load: 0.1%

  9. Computations Task Description: • Calculates data to be transmitted to the LED drivers • Priority #8 • Period: ~100ms (Sporadic) • Execution time(max): ~10ms • CPU load: ~10%

  10. User Interface Task Description: • Updates LCD, controls program states, and functionality of button presses • Priority: 9 • Period: 100ms(Sporadic) • Execution Time(max): ~10ms • CPU load: ~10%

  11. Total CPU Load L_max = 21.62% Average= 15%

  12. Module/Library Description 1/2

  13. Module/Library Description 2/2

  14. Data Flow Diagram 1/3

  15. Data Flow Diagram 2/3

  16. Data Flow Diagram 3/3

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