Documentation

This project is a course project in CS/ECE353 Microprocessor Systems @University of Wisconsin-Madison. In general, we implement an embedded version of Google Chrome’s T-rex Runner with some more interesting features using FreeRTOS.

You can find the source code in my Github repo.

Game Rules

Basic Google Chrome’s dinosaur T-rex runner game rules with following addional features:

• Cactus: generate randomly with hardware noise picked up in ADC
• Button: instant vertical jump (up/down)
• Joystick: control dinosaur’s horizontal positions (move left/right)
• Light sensor: play without button (wave hand in front of light sensor to jump)
• Accelerometer: contol dinosaur’s running speed (tilt left/right)

Hardware

• MSP-EXP432P401R with MKII Boosterpack from Texas Instruments.
• Peripherals:
  • LED
  • Button
  • Buzzer
  • Joystick
  • LCD Display
  • Light sensor
  • Accelerometer
• Working System Clock: 48 MHz

Software

• Programming Language: C
• IDE: Code Composer Studio
• Operating system transplant: FreeRTOS
  • Download source code from FreeRTOS official website
  • Version: FreeRTOS 202112.00
  • include path:
    • ${PROJECT_LOC}/FreeRTOS/Source/include
    • ${PROJECT_LOC}/FreeRTOS/Source/portable/CCS/ARM_CM4F
• Peripheral Communication Protocal: SPI and i2c

Implementation Details

• Random cactus generation: Hardware noise converted by ADC14 during periodic interrupts
• LCD update: handled with message queue Queue_LCD
  1. Future frame buffers are calculated in advanced and enqueued from Task_Game
  2. Current frame dequeued in Task_LCD to update LCD display
  3. 20ms delay is necessary in Task_Game to handle button/joystick/accelerometer data, otherwise delay would be observable.
  4. Dataflow controls by SPI synchronous communication protocol
• ACD notification:
  1. Task_XX_Timer: activate ADC to generate ADC interruption to step into interrupt handler ADC14_IRQHandler
  2. ADC14_IRQHandler: read ADC values sequence and turn on task notification for Task_XX_Bottom_Half
  3. Task_XX_Bottom_Half: waken by ADC14_IRQHandler and update joystick/accelerometer status