Introduction to RealTime Systems

1
Realtime Control Computer Software

• Embedded Systems
• Architecture
• Interrupt mechanism
• System
• Software Engineering
• Object-oriented programming concept
• Design technique
• Correctness of program

2
Architecture

• CPU, Memory, and Devices
• Input/Output Bus
• Addressing Devices/Memory Locations
• Interface with Devices

3
Typical Questions for Architecture

• How do we connect
• CPU, Memory, and Devices
• Addressing Devices/Memory Locations
• Device Enable Circuits (from address bus to
  device)
• Interface with Devices
• interrupts to inform CPU of changing of states of
  devices
• interrupts from CPU to change states of devices

4
Manipulation of Devices

• Interrupt Handling with Turbo C()
• Keyboard Interrupts
• Video Interrupts
• Timer

5
Manipulation of Devices

• Interrupt Handling with Turbo C()
• Keyboard Interrupts
• test of key input, read key numbers
• Video Interrupts
• color in graphical mode
• Timer
• get real time through interrupts

6
Control

• Human interface with program
• inform program through key interrupts
• interface with non-ascii keys
• conditional statements and loops

7
Embedded System Concept

• Processes
• executive processes
• user processes
• Sharing of Resources
• Time Sharing of CPU
• Memory
• Communication between processes
• Channels
• pools

8
Software Engineering

• Some useful tools and concepts
• the scope of a variable
• local
• global
• parameters for a function
• call-by-reference vs call-by-value
• hexadecimal numbers
• bitwise operations

9
Software Engineering

• OO Concepts
• ADT class/object
• Overloading of functions/operators
• Design
• Top-Down
• Function/class prototype header file
• Correctness
• debugging/testing/checking

10
OO-concepts

• ADT abstract data type, a concept independent of
  language. OO makes it is easier to design ADT
  with class/object
• Polymorphism overloading operators makes the
  effects of operations dependent on the object to
  which the operators are applied to

11
Design

• Top-down Design
• recursion
• divideconquer
• Prototype of Functions/Classes
• pre-conditions/post-conditions
• black-box analogue
• given prototype, implement it.

12
Debugging/Testing/Checking

• Debugging Try to locate errors
• Grammar Errors
• Run Time Errors
• Testing Searching for errors.
• developer tests (gently) for delivery of good
  product.
• expert tester tries to break product for quality
  guarantee.
• Checking Make sure the output for an input is OK
• an extra function accompanying a function
  which checks for correctness of the output for
  every run of the function.