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Software Design Review

Andres Rodriguez

General System Design MCU: STM32F405 MCU Bus Frequency: 84MHz Memory Requirements Flash: ~ 10Kb RAM: ~ 15Kb

Kernel: FreeRTOS RTOS Tick period 1ms

Kernel Selection Real-time preemptive

multitasking kernel

FreeRTOS

3. Start Task4. OutputLED Task5. Bluetooth Receive Task6. Motor Control Task7. LEDBufferUpdate Task

Priority of tasks

Start TaskDescription:

Initializes system, Creates other tasks and Sets semaphores and Flags to proper value to Ensures POV does not run until the User hits the “ON” button

Priority #3 Period: once (at start-up) Execution time ~ 10ms Average CPU Load N/A

Bluetooth TaskDescription:

Every 40ms checks for incoming Bluetooth data.If data ready to receive, receives first byte and uses it to sort the rest of the incoming data onto appropriate index of a structure and also sets variable used by Motor module to enable or disable motor.

Priority #5 Period: 40 ms (Periodic) Execution time ~ 430us Execution time ~ 1.6ms (max) Average CPU Load = 1.07 % Peak CPU Load = 4%

User InterFace (App)

Description: Allows user to turn motor on and off, change background color, change text color, enter text or choose pre-programmed animations.

Motor Task

Description: Checks the MotorEnable variable to Enable or

disable Motor. Maintains motor speed as close as possible to 1500 RPM and saves it to a variable that Output LED task can access Via mutex

Priority #6 Period: 200 ms (Periodic) Execution time ~ 20 us (max) Average CPU Load = 0.01%

LEDOutput TaskDescription:

Reads LED Buffer and outputs it to the LEDs at the correct refresh rate. Pends on mutex to acces LEDBuffer. Gets MotorSpeed from motor module to determine LED refresh rate. Priority #3 Period: 220 usec (Periodic) updating 180 times per revolution

Execution time ~ 110us (max) Avg CPU Load: 50%

LEDBuffUpdate TaskDescription:

Pends on a semaphore to read text and colors from structure and then waits for LEDBuff mutex to update the LEDBuff with the new buffer. Priority #7 Period: sporadic Execution time ~ 4.12 ms (max) assuming the array is for updating 180 times per revolution.

CPU Load: 0.824%Assuming Semaphore gets set every 500 ms

CPU load

L max= (20us) + (1.6ms) + (110us) + (4.12ms)

(200ms) (40 ms) (220us) (500ms)

L max= 54.83%

L average = 51.9 %

ModulesModule Tasks Public Functions DataMain.c Start Task

Bluetooth.cAdapted From STM32F4_USART Sample

BTReceiveTask Bluetooth_Init();Bluetooth_Put();SetMotorEnable();

LEDUpdate SemaphoreUserInput Structure

SPICom.c

Adapted From STM32F4_SPI Sample

LEDSPI_Init();RPMSPI_Init();LEDSPI_Send();RPMSPI_Send();

MotorControl.c MotorControlTask PWM_init(); Power Motor variableMotor Speed variable

LEDs.c OutputLED TaskLEDBuffUpdate Task

UpdateLEDBuff();GetMotorSpeed();GetColors();

LEDBuffer Array

Dataflow Diagram

Questions?