• Share
  • Email
  • Embed
  • Like
  • Save
  • Private Content
Programming Hardware Devices

Programming Hardware Devices






Total Views
Views on SlideShare
Embed Views



6 Embeds 318

http://d.hatena.ne.jp 294
http://lodhi.wikispaces.com 19
http://pmonline.parramarist.nsw.edu.au 2
http://www.slideshare.net 1
http://hrt.happy.nu 1
http://hatenatunnel.appspot.com 1



Upload Details

Uploaded via as Microsoft PowerPoint

Usage Rights

© All Rights Reserved

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
Post Comment
Edit your comment

    Programming Hardware Devices Programming Hardware Devices Presentation Transcript

    • Software Developers View of Hardware Programming Hardware Devices
    • What does this mean?
      • Computers usually interact with outside sources for input and output:
        • CD-ROM
        • Mouse
        • Keyboard
        • Scanner
        • Monitor.
    • What does this mean?
      • Most software developers require their software to interact with these devices.
      • So it is therefore important to understand how they are programmed and especially, how they operate.
      • Any hardware device that can be programmed uses two processes:
        • Sensor
        • Actuator
    • Sensor
      • Any device that converts input from the environment into a digital signal.
      • The signal is then interpreted by the software.
    • Actuator
      • An output device that performs a mechanical action.
      • Actuators receive digital signals from software.
    • Processing a Data Stream
      • What is a Data Stream?
      • A packet of binary data consisting of a header, data characters and a trailer.
      • For example:
      • Header Data Trailer
      • 010101 | 101010100 | 0101010
      • The information contains the data and a check to see if it is correct.
    • Processing a Data Stream
      • What is in the header?
      • Specifies how much data is to be transmitted.
      • Contain error checking data such as:
          • Parity Checking
          • CRC 16
      • Specifies the device in which it is coming from.
    • Processing a Data Stream
      • What is in the data section?
      • Includes control characters i.e SHIFT + B
      • All subsequent instructions to be processed by the CPU.
    • Processing a Data Stream
      • What is in the trailer section?
      • Data bits that end the block.
      • Error checking bits
      • Memory clear instructions.
    • Processing a Data Stream
      • Recognising and stripping control Characters
      • Control characters are represented by the ASCII values 0 – 31 and are typed while pressing the control key.
    • Processing a Data Stream
      • Counting the Data Characters
      • The header field will normally contain all required information relating to the size of data packets.
    • Processing a Data Stream
      • Extracting Data
      • Once the header and trailer have been removed, the hardware within the CPU will extract the data, and relevant software will carry out the instructions.
    • Keyboard Example
      • How a keyboard transmits data?
      • Pressing a key causes a change to take place in the amount of current flowing through key circuits.
      • A microprocessor sends a signal relating to the pressed key along a cable port notifying the BIOS.
    • Keyboard Example
      • The BIOS translates the codes into ASCII and that particular character or command is stored in memory.
    • Control Systems
      • These are systems that include hardware devices, software and especially the use of sensors and actuators.
      • There are two broad categories of control systems:
          • Open Control Systems
          • Closed Control Systems
    • Open Control Systems
      • These systems do not react to their environment.
      • These systems normally require a user to activate the actuator.
      • E.g. Hotel Door Lock.
    • Closed Control Systems
      • These systems actually react to their environment.
      • This system uses sensors and programmed structures to control the actuators.
      • For Example:
        • Anti-Lock Breaking System
    • Question 1
      • A robotic moon car is designed to use digital controls. The motor of the car receives the following commands from a user.
      Motor off. Stop Turns left X deg LeftX Turns right X deg RightX Moves in straight line at X speed. StraightX Trailer <-T Header ->H
    • Question 1
      • The speed for the car can range from + 100 (Fastest) to -100 (Backward)
      • 1.) Identify the category of control system.
      • 2.) Identify the problems with the following instruction:
      • ->HStraight20StopRight90Forward10->H
      • 3.) Construct a data stream to carry out the following tasks:
      • Move forward 30
      • Move left 45, move forward 80
      • Move right 20, backward -20, stop
    • Question 2
      • Complete the following text book questions:
      • SET 10F
      • Question 11
      • Question 13
      • Question 14