System Software Design Doorbell Jukebox Henry Arbicor and Arthur Bingcang

General System Design MCU – Freescale MCF52233 Bus Frequency – 60 MHz Memory Requirements ◦ 12 kB RAM ◦ 37 kB FLASH, no paging Timeslice Kernel ◦ Timeslice period: 10ms

Tasks 4) Start Task 5) MP3 Task 6) Push-button Task 7) LCD Task 8) Play Task

Start Task Initializes the system Sets up the order in which the other tasks will run Period: Once at Start-up Execution Time: 100ms

MP3 Task Reads MP3’s from MMC card and displays song names on the LCD Sets pointer that will move when different songs are selected Period: 100ms (periodic) Execution Time: 5ms

Push-button Task Recognizes push-button press De-bouncing Sets state ◦ Up ◦ Down ◦ Select ◦ Sequential ◦ Doorbell Period: 10 ms (sporadic) Execution Time: 5 us

LCD Task Display’s song names Adjusts display according to current state Period: 100ms (periodic) Execution Time: 2.5ms

Play Task When in Doorbell state, decodes and plays the selected song Period: 10ms (periodic) Execution Time: 3ms

CPU Load Load (max) = 5ms/100ms + 5 us/10ms + 2.5ms/100ms + 3ms/10ms =.3755 = 37.55% Load (average) = 5ms/100ms + 2.5ms/100ms =.075 = 7.5%

Modules TasksPublic Functions and Data Jukebox.c Start Task MP3 Task Push-button Task LCD Task Play Task PlaySong() StopSong() LCD.c By Todd Morton NoneAll LCD Functions OCDelay.c By Todd Morton NoneOCDelay() OCDelayInit() Coldfire MP3 Decoder Interface By Motorola Embedded File Systems Library By Lennart Ysboodt, Michael De Nil

Dataflow Diagrams: LCD Jukebox.cLCD I/O Push- button Task MP3 Task LCD Task LCD Button

Dataflow Diagrams: Audio Out MMC Card MP3 Task Push- button DAC Clock Speaker Play Task Jukebox.c External Hardware