BICYCLE INFORMATION TRACKING SYSTEM

System Software Design Review

BITS General System Software Design

MCU: NXP LPC2378 ARM7 32-bit 512 KB Flash, 8KB EEPROM and SRAM

Bus Frequency: 20 MHz Approximate Memory requirements:

ROM: ~220 KB maximum Includes FatFS file system, drivers for all

peripherals RAM: ~2 KB SD Card: 1 KB on a FAT formatted 256 MB card

Resources used: 5 GPIO, 1 SPI, Micro-SD card

BITS System Software Design: Kernel

Timeslice based system Shared resources use flags

FatFS file system Open-source system for SD card read/write

Tick period: 1 ms Number of tasks: 4

AppInit, Input Task, SDCard, UI Display

BITS System Software Design: Tasks

Start Task Initializes all resources including LCD, SD card, and GPIO,

checks SD card for previous data. Displays splash screen Only runs at beginning Execution time: 3 seconds

Input task Monitors GPIO port P3 for input from Hall Effect Sensor

Uses this information to perform calculations Monitors GPIO port P4 for input from switches, as well as

information from the touchscreen Toggles turn signals, changes data shown on screen

Monitors input from Touch Screen Period: 1 ms Execution time: ~10 us

BITS System Software Design: Tasks

SDCard task Writes strings and data to SD card when

prompted by the user Period: ~20 ms (Sporadic) Execution time: ~3 ms

UI Display task Controls displayed information on the screen

based on Touchscreen/GPIO input, also calculates information obtained from P3 to determine distance and speed.

Period: ~10 ms Execution time: ~1 ms

BITS System Software Design: Tasks

Maximum CPU load: 26%

Average CPU load: 8%

BITS Data Flow: GPIO/Touch Task

BITS Data Flow: UI Task

BITS Data Flow: SD Card Task

BITS Data Flow: State Diagram

BITS Modules and Functions

Microsoft Excel Worksheet

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