System Software Design Doorbell Jukebox Henry Arbicor and

System Software Design Doorbell Jukebox Henry Arbicor and Arthur Bingcang

General System Design MCU – Freescale MCF 52233 Bus Frequency – 60 MHz Memory Requirements ◦ 12 k. B RAM ◦ 37 k. B FLASH, no paging Timeslice Kernel ◦ Timeslice period: 10 ms

Tasks 4) 5) 6) 7) 8) Start Task MP 3 Task Push-button Task LCD Task 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: 100 ms

MP 3 Task Reads MP 3’s from MMC card and displays song names on the LCD Sets pointer that will move when different songs are selected Period: 100 ms (periodic) Execution Time: 5 ms

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: 100 ms (periodic) Execution Time: 2. 5 ms

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

CPU Load (max) = 5 ms/100 ms + 5 us/10 ms + 2. 5 ms/100 ms + 3 ms/10 ms =. 3755 = 37. 55% Load (average) = 5 ms/100 ms + 2. 5 ms/100 ms =. 075 = 7. 5%

Modules Tasks Jukebox. c Public Functions and Data Start Task MP 3 Task Push-button Task LCD Task Play Task LCD. c None All LCD Functions None OCDelay() OCDelay. Init() By Todd Morton OCDelay. c By Todd Morton Coldfire MP 3 Decoder Interface By Motorola Embedded File Systems Library By Lennart Ysboodt, Michael De Nil

Dataflow Diagrams: LCD Jukebox. c LCD I/O Push-button Task Button MP 3 Task LCD

Dataflow Diagrams: Audio Out Jukebox. c External Hardware MMC Card MP 3 Task DAC Pushbutton Clock Play Task Speaker