Course Profile   Computer Engineering, Grade 11, University/College Preparation, Catholic and Public

 

Unit 5:  Computer Interfacing

Time:  30 hours

 

Activity 1 | Activity 2 | Activity 3 | Activity 4 | Activity 5

Unit Description

Students design, build, and operate interfacing systems. Students apply and integrate their hardware and software knowledge from the previous four units in designing and building systems for communicating between the computer and peripheral devices. Students also research the social impact of hardware development and identify related engineering careers. Students also explore the possibilities for solutions to social and environmental moral and ethical problems through computer technology.

Unit Synopsis Chart

Activity

Time

Expectations

Assessment

Tasks

1. What is Interfacing?

1 hour

TVF.01, TF2.01,

CGE2b, CGE2e, CGE3f, CGE7i, CGE7j

Knowledge/ Understanding

Identifying interface hardware and software components and terminology.

2. Interfacing Software

6 hours

TVF.05, TF1.02, SPV.01, SP1.01, SP3.01, SP3.02,

CGE3b, CGE3c, CGE4f

Thinking/Inquiry Application

Applying computer programming concepts of Unit 4 to the software needed for particular interfacing systems.

3. Interfacing Hardware Design

5 hours

TVF.01, TF2.02, SP2.02,

CGE3b, CGE4f

Knowledge/ Understanding Thinking/Inquiry

Students design hardware interfaces and peripherals for the interfacing systems to be built in Activity 4.

4. Building, and Operating an Interface System

15 hours

TVF.01, TF2.02, SPV.02, SP1.03, SP2.01, SP2.02

CGE3b, CGE3c

Application Communication

Construct and operate entire interfacing systems. Include programming software and design work in portfolio.

5. Impact of Computer Technology and Related Careers

3 hours

ICV.03, ICV.04, IC1.02, IC1.03, IC1.05, IC1.06, IC1.07

CGE3b, CGE3f, CGE4f, CGE5a

Thinking/Inquiry Communication

Explore the social impact of computer technology and career opportunities in engineering.

 

Activity 1:  What is Interfacing?

Time:  60 minutes

Description

Students are introduced to the electronic hardware and software components of commercial and hand-built interfacing systems. Students explore possible project ideas through investigation and research, leading to their own computer interface system. Students also explore ethical and moral use of computer technology as caring stewards of society and the environment.

Strand(s) & Learning Expectations

Strand(s):  Theory and Foundation

Overall Expectations

TVF.01 - identify the function and interaction of basic computer components and peripherals.

Specific Expectations

TF2.01 - explain the function and interaction of the basic components (e.g., CPU, I/O devices, memory) of a computer system;

Ontario Catholic School Graduate Expectations

CGE2b - reads, understands and uses written materials effectively;

CGE2e - uses and integrates the Catholic faith tradition, in the critical analysis of the arts, media, technology, and information systems to enhance the quality of life;

CGE3f - examines, evaluates and applies knowledge of interdependent systems (physical, political, ethical, socio-economic and ecological) for the development of a just and compassionate society;

CGE7i - respects the environment and uses resources wisely;

CGE7j - contributes to the common good.

Prior Knowledge & Skills

·         hardware familiarization from Unit 1

·         networking terminology from Unit 2

·         hands-on integrated circuit activities from Unit 3

Planning Notes

·         Review programming software basics to control interfaces (introduced in Unit 4).

·         Catalogue on-hand electronic components to build interfaces and peripherals (see Activity 4).

·         Review software to design interfacing circuits.

·         Organize this activity considering hands-on work in Activity 4.

Teaching/Learning Strategies

1.   Teacher initiates discussion on ethical design practices and make students aware of responsibility to promote Christian values and ensure ethical and socially responsible use of computer technology in society. Situations to consider include: intellectual property rights and illegal copying of software, reverse engineering, creation and distribution of viruses or other destructive devices, computers and privacy issues, environmental impact of computer technology (good or bad).

2.   Students develop a list of responsible computer (and interface) use to be written on chart paper and displayed in class. (Possible uses include alarms and other safety devices, devices to assist people with special needs, early warning systems for navigation or shipping, devices that improve the workplace by reducing or eliminating menial tasks).

3.   Review the safety considerations when working with computer internals and with electronic components.

4.   Introduce the types of small- and large-scale interfaces. (An example of a small-scale interfacing system could be a computer controlling a single LED, a large scale interfacing system could be a computer controlling a robot).

5.   Other interfacing systems that might be considered are:

·         three LEDs simulating a stop light

·         twelve lights simulating traffic control at an intersection

·         eight lights demonstrating counting from 0 to the maximum value stored in one byte (i.e., 255)

·         eight lights demonstrating the binary ASCII values of any character

·         simulation of stereo indicator lights

·         multiple LEDs demonstrating seven segment displays

·         simulation of safety or warning indicator lights

·         one DC motor

·         one DC motor installed in a vehicle

·         one motor installed in a toy ( e.g., merry-go-round)

·         multiple motors

·         combinations of lights and motors (e.g., amusement park rides).

6.   Outline the organization of the main interfacing components (computer, interface, peripheral) using precise terminology (Refer to Activity 3 and 4 in the Grade 10 Computer Engineering Profile).

7.   Students should complete the knowledge-building exercise (Appendix 5.1.1 – Discrete Electronic Components) to familiarize themselves with discrete electronic components and their function.

8.   Demonstrate how the computer communicates with the interface using the discrete electronic components.

Assessment & Evaluation of Student Achievement

Develop rubric to assess the student’s proper identification of electronic components.

Accommodations

·         Review vocabulary and definitions prior to and in context of lesson when necessary.

·         Monitor individual submissions and progress to allow extra time or further review work as needed.

·         Allow for oral testing (vs. written testing) for students with special needs when measuring skill and ability.

·         Make appropriate accommodations based upon recommendations in exceptional students’ IEPs.

Resources

Software

Ministry licensed word processor or spreadsheet.

Print

Barbarello, James. Real World Interfacing with Your PC. Indianapolis: Howard W. Sams & Co., 1996.
ISBN 0-7906-1145-7

Bergsma, Paul. Controlling the World with Your PC. California: High Text Publications Inc., 1994.
ISBN 1-878707-15-9

Simms, Forrest. Getting Started in Electronics. USA: Radio Shack, 1983. Cat No 276-5003

Smyth, Graham and Christine Stephenson. Computer Engineering: An Activity-Based Approach. Toronto: Holt Software Associates, 2000. ISBN 0-921598-36-X

Appendix 5.1.1

Discrete Electronic Components

Individual electronic components such as LEDs, resistors, transistors, small DC motors and breadboards must be clearly understood before complete interfacing systems can be built. Define the following interface terminology by reading the specifications on the component packages, accessing Internet electronic terminology sources, and/or reading computer programming software manuals or obtaining resource material from your teacher.

1.   An acronym is a word formed from the initial letter(s) of words (e.g., CPU is an acronym for Central Processing Unit, LORAN is an acronym for LOng RAnge Navigation). What is LED an acronym for?

2.   a)   Draw a physical diagram of an LED and label the positive and negative leads.

b)   Draw an electronic schematic of an LED.

3.   Compare the lengths of the two leads. How is the positive lead on an LED distinguished from the negative lead?

4.   Examine the base of an LED. One side of the base is slightly flattened. Which lead is associated with the flattened side?

5.   What is the maximum voltage required by an LED?

6.   What is the voltage output from the parallel port output pins?

7.   a)   Describe the exterior physical characteristics of a resistor.

b)   Draw an electronic schematic of a resistor.

8.   What units are used to measure resistance?

9.   Using a chart of resistor values, state the value of the resistor given the state of the three colour bands.

a)   Red, red, brown

b)   Orange, orange, brown

c)   Red, black, red

d)   Orange, yellow, green

10.  Given the following resistor values in ohms, describe the three colour bands on the resistor.

a)   220

b)   330

c)   500

d)   5 300 000

11.  What is a breadboard?

12.  Draw a labelled diagram of a breadboard that includes:

a)   top horizontal bar

b)   bottom horizontal bar

c)   centre dividing line

d)   vertical connecting columns

e)   describe which groups of holes in the breadboard are connected internally.

 

Activity 2:  Interfacing Software

Time:  300 minutes

Description

Students develop software for controlling computer interfaces. The software that students design and write in this activity leads to the fabrication of an interfacing system in Activity 4. This software will control input and output of a system consisting of a computer, interface, and a hardware device. Students consider the care of systems and facilities in light of the common good.

Strand(s) & Learning Expectations

Strand(s):  Theory and Foundation, Skills and Processes

Overall Expectations

TVF.05 - describe a problem-solving model and the fundamental programming constructs required to implement it.

SPV.01 - use internal numbering, character representation systems, and logic gates.

Specific Expectations

TF1.02 - identify standard ways of representing characters (e.g., ASCII, EBCDIC).

SP1.01 - perform base-to-base conversions;

SP3.01 - use design tools to plan programming solutions (e.g., flow charts, pseudo-code, structure charts);

SP3.02 - apply fundamental programming constructs by writing, testing, and debugging programs.

Ontario Catholic School Graduate Expectations

CGE3b - create, adapt, and evaluate new ideas in light of the common good;

CGE3c - think reflectively and creatively to evaluate situations and solve problems;

CGE4f - apply effective communication, decision-making, problem-solving, time and resource management skills.

Planning Notes

·         Select suitable programming software (e.g., Turing, Visual Basic) that supports access to the parallel port and possible graphics and mouse control as enrichment activities (see Appendix 5.3.4. – Enrichment Mouse Activities).

·         During this programming activity consider the construction of the interfacing system in Activity 4.

·         Consideration must be given to possible conflicts between the operating system software and programming software as to which has control of the parallel port.

·         Consideration must also be given to possible problems when students have access to the operating system while programming. For example, students can format drives, add or remove programs, send data that will control inappropriate hardware such as projectile launchers. One approach would be to obtain from business, industry or academic institutions a set of older computers. These computers can be assembled/disassembled and have operating and network software installed/removed with no disruption to the main school network. If appropriate, groups could be assigned the same computer for a block of time and hence assure continuity of a project.

Prior Knowledge & Skills

·         Unit 3, hands-on integrated circuit activities

·         Unit 3, number system arithmetic and conversions

·         Unit 4, computer programming activities

Teaching/Learning Strategies

1.   Teachers review base 10, hexadecimal and binary number system conversions as appropriate to the programming language selected (see Appendix 5.2.1 – Number Systems and Appendix 5.2.2 – Binary Representation of Numbers).

2.   Students apply the software concepts from Unit 4 to include interface commands to turn a simple LED on and off through the parallel port (see Activity 3, Appendix 5.3.1 and Appendix 5.3.2 for programming considerations).

3.   Review programming style introduced in Unit 4 when writing programs (including program identification, proper indentation, and documentation).

4.   Teachers review each fundamental programming structure (to include input/output, decision, and looping) as necessary to control the interface.

5.   Students write programs that apply character representation systems such as ASCII. For example, in Turing, the command put ord (“A”) will display the number 65 on the screen since 65 is the ASCII equivalent of A. These commands can be used in programs to explain how all characters are assigned specific numbers that can be represented in base 10, binary or hexadecimal.

Assessment & Evaluation of Student Achievement

Students are assessed on test(s) or assignment(s) that include the use of proper programming style and structure. Students are evaluated on Appendices 5.2.1, 5.2.2

Accommodations

·         Provide printed materials such as examples of programs that demonstrate interfacing concepts or additional help with problem solving model examples when necessary.

·         Adapt time constraints on the programming test when necessary.

·         Pair students to accommodate need for remediation or enhancement.

·         Incorporate mouse control and graphics as possible enrichment assignment (Appendix 5.3.4 – Enrichment Mouse Control).

·         Make appropriate accommodations based upon recommendations in exceptional students’ IEPs.

Resources

Software

Computer programming software (possibly same software used in Computer and Information Science).

Print

Barbarello, James. Real World Interfacing with Your PC. Indianapolis: Howard W. Sams & Co., 1996.
ISBN 0-7906-1145-7

Bergsma, Paul. Controlling the World with Your PC. California: High Text Publications Inc., 1994.
ISBN 1-878707-15-9

Smyth, Graham and Christine Stephenson. The Don’t Panic Guide to Programming. Toronto: Holt Software Associates, 1999. ISBN 0-921598-33-5

Smyth, Graham and Christine Stephenson. Computer Engineering: An Activity-Based Approach. Toronto: Holt Software Associates, 2000. ISBN 0-921598-36-X

Websites

Turing and OOT – http://www.holtsoft.com/turing/resources.html

The QBasic Page – http://www.qbasic.com/qbindex.shtml

Appendix 5.2.1

Number Systems

An interfacing system consists of a computer, interface, and peripherals. The computer is able to communicate with the interface through the parallel port. The computer sends commands (signals) to the parallel port using a programming language. The programming language uses either a base 10 or a hexadecimal number system (depending on the language) when communicating with the parallel port. The software can be written in any of several languages (such as Visual Basic, Turing and Pascal). All languages eventually translate their numbering system to binary at the parallel port. Therefore an understanding of the relationships among binary, hexadecimal, and base 10 is essential. The language chosen should easily communicate with the parallel port and possibly support graphics and access the mouse commands as enrichment activities.

By answering the following questions, students should gain a better understanding of how the software communicates with the interface. See for reference the software-programming manual, software websites, and material listed in Resources.

1.   Since the source code for programming languages uses either base 10 or hexadecimal when sending the parallel port commands, conversions among the three systems should be understood. Complete the following chart that relates binary, decimal, and hexadecimal systems.

 

Base 10 (Decimal)

Base 16 (Hexadecimal)

Base 2 (Binary)

0

 

 

1

 

 

2

 

 

3

 

 

4

 

 

5

 

 

6

 

 

7

 

 

 

Base 10 (Decimal)

Base 16 (Hexadecimal)

Base 2 (Binary)

8

 

 

9

 

 

10

 

 

11

 

 

12

 

 

13

 

 

14

 

 

15

 

 

 

Appendix 5.2.1  (Continued)

2.   Larger binary, hexadecimal, and decimal numbers must also be converted so they can be used when communicating with the parallel port. Complete the chart.

 

Question No.

Binary number

Decimal number

Hexadecimal number

1

1111

 

 

2

1010 1111

 

 

3

 

255

 

4

 

128

 

5

 

 

11

6

 

 

FF

 

3.   How many pins on the parallel port are normally reserved for outputting data?

4.   What is the smallest number that can be output on the parallel port in base 10, 2, and 16?

5.   What is the largest number that can be output on the parallel port in base 10, 2, and 16?

6.   When a Base 10 number is sent to the parallel port, the binary equivalent is actually output on pins labelled D0, D1, D2 … D7. Complete the chart that relates the Base 10 number and the equivalent number on the output pins of the parallel port.

 

Number

D0

D1

D2

D3

D4

D5

D6

D7

1

 

 

 

 

 

 

 

 

15

 

 

 

 

 

 

 

 

255

 

 

 

 

 

 

 

 

18

 

 

 

 

 

 

 

 

 

Appendix 5.2.2

Binary Representation of Numbers

Some programming languages use the hexadecimal number system in the programming language to send information to the parallel port. The information at the parallel port has been translated to binary by the programming language being used. This sheet examines the relationship between binary, decimal, and hexadecimal number systems

Memory is used to store information inside the computer. Computer memory is divided into bits and bytes (8 bits). Each bit is a one or a zero; the combination of ones and zeros in a byte would allow the storage of letters and numbers.

One byte can store a number up to 255. The following is a representation of a byte:

128

64

32

16

8

4

2

1

0

1

1

0

1

0

0

1

Each bit represents a power of 2 just as in our number system each digit represents a power of 10. All the numbers between 0 and 255 can be represented as a combination of bits. The number above is 105 or 64+32+8+1.

1.   What numbers are each of the following?

a)

 

128

64

32

16

8

4

2

1

 

1

0

1

0

1

0

1

0

b)

 

128

64

32

16

8

4

2

1

 

0

1

1

1

1

0

1

0

c)

 

128

64

32

16

8

4

2

1

 

1

0

0

0

0

0

1

0

d)

 

128

64

32

16

8

4

2

1

 

0

1

1

1

1

0

1

0

 

2.   Determine the bit pattern for each of the following numbers

a)

43

128

64

32

16

8

4

2

1

 

 

 

 

 

 

 

 

 

b)

107

128

64

32

16

8

4

2

1

 

 

 

 

 

 

 

 

 

c)

231

128

64

32

16

8

4

2

1

 

 

 

 

 

 

 

 

 

d)

85

128

64

32

16

8

4

2

1

 

 

 

 

 

 

 

 

 

Activity 3:  Interfacing Hardware Design

Time:  240 minutes

Description

Students design a hardware interface and related peripherals using a computer science problem-solving model. Students learn to design interfacing systems based on given situations, ranging from simple LED lights to more complex motor controllers. Design decisions based on ethical and moral use of computer technology is stressed.

Strand(s) & Learning Expectations

Strand(s):  Theory and Foundation, Skills and Processes

Overall Expectations

TVF.01 - identify the function and interaction of basic computer components and peripherals.

Specific Expectations

TF2.02 - describe the function and interaction of computer peripherals (e.g., mouse, keyboard, screen, printer).

SP2.02 - verify the correctness of the input and output of a system consisting of a computer, interface, and a hardware device.

Ontario Catholic School Graduate Expectations

CGE3b - create, adapt, and evaluate new ideas in light of the common good;

CGE4f - apply effective communication, decision-making, problem-solving, time and resource management skills.

Prior Knowledge & Skills

·         Computer hardware component background from Unit 1

·         Hands-on integrated circuit activities from Unit 3

·         Understanding of electronic components discussed in Unit 5, Activity 1

Planning Notes

·         Initial interfacing systems should be based on controlling LEDs since they are versatile, inexpensive, and expandable. A simple one LED system can be expanded to three LEDs simulating a stoplight, or twelve lights simulating traffic control at an intersection, or eight lights demonstrating binary counting and binary ASCII character representations, or multiple LEDs simulating stereo indicator lights. A simple DC motor interfacing system can be used as in a vehicle or other toy such as a merry-go-round. Combinations of lights and motors can simulate amusement park rides. Subsequent interfacing systems could control several motors that can be expanded into computer-controlled cars or robots.

·         Select suitable method to design interfacing hardware (e.g., pencil/paper, computer-assisted design). Initial designs should be sketched with pencil/paper.

·         Design must take into consideration the availability of electronic components.

·         During the design activity, consider possible projects for Activity 4 such as light controls (low voltage LEDs), motor controls (low voltage DC), or construction and control of small vehicles or robots. Start by mounting one LED on a breadboard and writing software that will flash the LEDs in repeat patterns or output Morse code signals. In a similar fashion three LEDs can be mounted on a small stand to simulate traffic lights.

·         Design considerations should include possible coordination with other Technological Studies subjects to assist in fabrication of the peripheral system (i.e., construction or manufacturing shop).

Teaching/Learning Strategies

1.   Teachers review ethical issues discussed in Activity 1.

2.   Teachers should review safety considerations when handling electronic hardware.

3.   All designs should follow from the simple (e.g., one LED) to the complex (e.g., motors and lights), each design based on previous accomplishments.

4.   Teachers outline the function of an interface in an interfacing system (Refer to Appendices 5.4.2 and 5.4.3 of the Grade 10 Computer Engineering Profile)

5.   Teachers review discussions on how information flows into and out from the interface, and various electronic components used in interface fabrication.

6.   Students design interfaces (Refer to the Grade 10 Profile, Appendix 5.4.2 – Interfacing one Bit, and Appendix 5.3.2 – Interfacing one Byte, and Appendices 5.3.1 to 5.3.4 of this profile).

Assessment &Evaluation of Student Achievement

Students are assessed and evaluated on quality and demonstrated learning of their assignment on design of an interfacing system that controls a peripheral such as a light, combination of lights, a small DC motor, several motors, small vehicle, or robot.

Accommodations

·         Teachers should select the level of difficulty of the assignment based on individual student level of comprehension and background.

·         Students with experience in the TEE2O Engineering course will be familiar with basic interface design and therefore require less review of basic concepts and could assist other students.

·         More advanced designs can be used as enrichment projects.

·         Make appropriate accommodations based upon recommendations in exceptional students’ IEPs.

Resources

Software

Computer programming software

Print

Barbarello, James. Real World Interfacing with Your PC. Indianapolis: Howard W. Sams & Co., 1996.
ISBN 0-7906-1145-7

Bergsma, Paul. Controlling the World with Your PC. California: High Text Publications Inc., 1994.
ISBN 1-878707-15-9

Powers, Thomas. The Integrated Circuit Hobbyist’s Handbook. California: High Text Publications, Inc., 1995. ISBN 1-878707-12-4

Smyth, Graham and Christine Stephenson. Computer Engineering: An Activity-Based Approach. Toronto: Holt Software Associates, 2000. ISBN 0-921598-36-X

Websites

Parallel port Central – http://www.lvr.com/parport.htm

Turing and OOT – http://www.holtsoft.com/turing/resources.html

The QBasic Page – http://www.qbasic.com/qbindex.shtml

Appendix 5.3.1

Communication Between Computer and Interface

The student must understand the configuration of the parallel port in order to use it to control peripherals. The following questions attempt to clarify the specific function and naming of individual pins on the parallel port. Refer to computer software manuals, websites, and other material from Resources.

1.   What is one purpose of the parallel port?

2.   Where is the parallel port located?

3.   How many pins are located on the parallel port?

4.   Draw a diagram of the parallel port as viewed from the back of the computer. Number all pins.

5.   How many pins are output pins?

6.   Which pins function as grounds?

7.   What is the pin number of the first output pin? This pin is traditionally named D0.

8.   The output pins are traditionally labelled D0, D1, D2, … and D7, and have associated pin numbers. Complete the following chart.

 

Parallel port Pins

Pin label

D0

D1

D2

D3

D4

D5

D6

D7

Pin number

 

 

 

 

 

 

 

 

 

9.   Generally a parallel cable connects the parallel port in the back of a computer to a printer. Parallel cables can be custom-built for applications beyond computer/printer connections. What is the name of the connector at the end of a parallel cable that plugs into parallel port?

10.  Describe how wires can be attached to the parallel port.

11.  What command(s) will send information to the parallel port in the language you are using.

12.  Write a program that will allow the user to send a high or a low signal to a peripheral.

13.  Write a program that will count from 0 to 255 and send each of these numbers in binary form to eight LEDs.

14.  Write a program that will allow the user to enter a character and output that character in ASCII to eight LEDs.

15.  Write a program that will allow the user to enter their name. The program should send each ASCII value in their name to eight LEDs.

16.  A traditional interfacing system is composed of a computer, an interface, and a peripheral. A very simple interfacing system could be used to control an LED. In this kind of interface, the computer would be connected to the peripheral (LED) by two wires that run from the computer, via the parallel port, to the peripheral.

In more sophisticated interfacing systems, where higher voltage lights or motors are being controlled, the interface could consist of many electronic components. List five other interfacing systems and in each case name the peripheral being controlled.

Appendix 5.3.2

Parallel port Control using Visual Basic

Visual Basic does not support access to the parallel port directly. A separate dll file must be included with the Visual Basic program to permit input and output from the parallel port.

Documentation for inpout32.dll when using Visual Basic.

Source: www.lvr.com/parport.htm

Inpout32 is a DLL that enables direct reading and writing to I/O ports in 32-bit Visual Basic programs.

by Jan Axelson (email: jaxelson@lvr.com)

Important information and cautions

1.   Inpout32 was developed to allow access to parallel ports and other ports on custom hardware, but you can use it to attempt to access any hardware that is mapped as an I/O port. Health and safety precautions when handling any electronic components must be observed.

2.   Use this DLL only with 32-bit programs. 16-bit programs require a 16-bit DLL.

3.   Windows 95 allows direct port reads and writes unless a Vxd has control of the port and blocks access. Under Windows NT, direct port access is not allowed, and you must use a kernel-mode device driver.

4.   For the latest parallel-port programming and interfacing information, visit Parallel Port Central at: http://www.lvr.com

 

These are the inpout32 files

·         inpout32.dll A DLL that adds Inp and Out to 32-bit Visual Basic 4 programs.

·         inpout32.bas Visual Basic declarations for Inp and Out

·         inpout32.vbp Visual Basic 4 test program for inpout32

·         inpout32.frm Startup form for the test program

·         inpout32.dpr  Source code for inpout32.dll. The DLL was compiled with Borland’s Delphi 2.0 Object Pascal compiler.

 

How to use inpout32

1.   Copy inpout32.dll to one of these locations: your default Windows directory (usually\Windows), your Windows system directory (usually \Windows\system), or your application's working directory.

2.   Add inpout32.bas to your Visual Basic project (File menu, Add File).

3.   Use this syntax to write to a port: Out PortAddress, ValueToWrite  (Example: Out &h378, &h55 )

4.   Use this syntax to read a port: ValueRead = Inp(PortAddress)  (Example: ValueRead = Inp(&h378) )

(The syntax is identical to QuickBasic’s Inp and Out).

 

How to run the test program (inpout.vbp)

1.   Copy inpout32.dll to your default Windows directory (or other directory as described above).

2.   Open the project inpout32.vbp.

3.   In the Form_Load subroutine, set PortAddress equal to the port address you want to test.

4.   Clicking the command button causes the program to write a value to the port. Each click increments the value, resetting to 0 at 255.

Appendix 5.3.3

DC Motor Interface Design

Purpose: To design the interface that will receive signals from the computer and translate them into signals for the peripheral (in this example, it is the motor).

Theory: D0 is the first output pin on the parallel port. By setting it high, the base pin of the transistor (here a TIP31) will be set high. This will permit electrons to flow from the ground to the +5V through the motor. The motor will therefore turn on. By setting D0 low, the motor will turn off. The 1K resistor will reduce the current to the base of the transistor since the base current requirements are low.

 

 

Safety Note 1: The voltage requirements of the motor and the power supply (here +5V) should be matched.

Safety Note 2: The voltage and current requirements of the motor must not exceed the capabilities of the transistor.

Appendix 5.3.4

Mouse Control – Enrichment

Mouse and graphic commands are interrelated. The graphic commands are useful for displaying diagrams that represent the actual real-world peripheral being controlled by the computer. The mouse commands are also useful for selecting graphic options displayed on the screen. When an option is selected by clicking, the software takes appropriate action and sends commands through the parallel port. The real-world object being controlled is activated at the same time as the screen graphic. Graphical user interfaces (GUIs) are very popular commercially.

A graphical interface can make an interfacing project easier to operate. A mouse clicking on a graphic to activate the peripheral is easier to use than a text-based system. This is similar to the advantage the Windows operating system (a graphics based interface) has over DOS (a character based system).

1.   Write a program to display the representation of a motor on the screen.

2.   Write a program to represent the motor turning clockwise for three seconds and then stopping.

3.   Write a program that represents the motor turning clockwise for three seconds and then turning off for two seconds. This process should repeat 20 times.

4.   Write a program that displays four small boxes and the motor on the screen. The first box contains the word CLOCKWISE. The second box contains the words COUNTER CLOCKWISE. The third box contains the word STOP. The fourth box contains the word EXIT. The program should turn the motor clockwise when the first box is clicked, counter clockwise when the second box is clicked; stop when the third box is clicked and exit the program when the fourth box is clicked.

Activity 4:  Building, and Operating an Interface System

Time:  900 minutes

Description

Students integrate knowledge of software, hardware theory and practice gained from the previous activities to build and operate complete interfacing systems. They adapt their understanding of troubleshooting, hardware configuration, and computer programming to solve challenges in a wide variety of computer interfacing and computer-based mechanism situations. Activities 4 and 5 are culminating activities for the course. The ethical use of computer technology to improve life is reinforced.

Strand(s) & Learning Expectations

Strand(s):  Theory and Foundation, Skills and Processes

Overall Expectations

TVF.01 - identify the function and interaction of basic computer components and peripherals;

SPV.02 - construct systems that use computer programs to interact with hardware components.

Specific Expectations

TF2.02 - describe the function and interaction of computer peripherals (e.g., mouse, keyboard, screen, printer);

SP1.03 - build an interface that visually displays internal representations of numbers and characters;

SP2.01 - build interfaces that control hardware components (e.g., LEDs, direct current motors, and stepper motors);

SP2.02 - verify the correctness of the input and output of a system consisting of a computer, interface, and a hardware device.

Ontario Catholic School Graduate Expectations

CGE3b - create, adapt, and evaluate new ideas in light of the common good;

CGE3c - think reflectively and creatively to evaluate situations and solve problems.

Prior Knowledge & Skills

·         Unit 1, hardware components

·         Unit 3, integrated circuits to build the interface

·         Unit 4, programming background to write software

·         Unit 5, Activity 2, interfacing software application

·         Unit 5, Activity 3, interface design concepts

Planning Notes

·         Plan suitable interfacing projects such as interfacing a light, combination of lights, traffic lights (scale model or real-world, a DC motor, several motors, small vehicle, or a robot).

·         Consideration must be given to the opportunities and limitations of available hardware and software.

·         Consider ethical issues that may emerge during these projects (such as taking credit for work done by others, using components that belong to others, or suitability of final project to the common good).

·         Gather pricing information for electronic components required when assemble interfaces and peripherals.

Teaching/Learning Strategies

1.   Teachers review safety precautions when handling computer and electronic components (Appendix 1.1.2 from the Grade 10 Computer Engineering Profile).

2.   Relate the concepts of current flow and complete circuits to their background in elementary science classes or in secondary school, General Science in Grade 9 or electricity in Physics or electricity/electronics in Broad-based Technology.

3.   Teachers initiate discussions on specific hardware and software components of an interfacing system (Appendices 5.1.1, 5.4.1, and 5.4.2).

4.   Teachers initiate review discussions on how software and hardware components communicate (Appendices 5.4.1 and 5.4.2).

5.   Students relate the electronic components from Activity 1, interfacing software of Activity 2, and interfacing hardware design of Activity 3 to the building of a complete system where hardware communicates with software (Appendices 5.4.1 and 5.4.2).

6.   Students develop a complete interfacing system by relating the hardware components from Unit 1, the necessary network concepts from Unit 2, the integrated circuits from Unit 3, the computer programming from Unit 4, and the design and programming of interfaces from Unit 5. Systems can be developed individually or in groups.

7.   Test and trouble shoot each step along the project (Appendix 5.4.3).

8.   Teachers facilitate the building of a complete interfacing system (Appendix 5.4.1 – Interfacing a DC Motor and Appendix 5.4.2 – Interfacing LEDs Using Visual Basic).

Assessment & Evaluation of Student Achievement

·         Projects are assessed on organization, accuracy, completeness, neatness, documentation, and originality, with consideration of level of difficulty and effort.

Accommodations

·         Student leaders with a higher level of interfacing experience could be paired with classmates requiring remedial work or extra assistance to promote a positive accepting environment.

·         Students requiring enrichment programming and interfacing could develop additional GUI and mouse control options for their interfacing system (Appendix 5.2.5 – Enrichment Mouse Control).

·         Make appropriate accommodations based upon recommendations in exceptional students’ IEPs.

Resources

Software

Computer programming software

Print

Axelson, Jan. Parallelport Complete. Wisconsin: Lakeview Research, 1998. ISBN 096508191-5

Barbarello, James. Real World Interfacing with Your PC. Indianapolis: Howard W. Sams & Co., 1996.
ISBN 0-7906-1145-7

Bergsma, Paul. Controlling the World with Your PC. California: High Text Publications Inc., 1994.
ISBN 1-878707-15-9

Lawrence, Orville. Computer Technology. Toronto: McGraw-Hill Ryerson, 1984. ISBN 0-07-548711-X

Powers, Thomas. The Integrated Circuit Hobbyist’s Handbook. California: High Text Publications, Inc., 1995. ISBN 1-878707-12-4

Simms, Forrest. Getting Started in Electronics. USA: Radio Shack, 1983. Cat No 276-5003

Smyth, Graham and Christine Stephenson. The Don’t Panic Guide to Programming. Toronto: Holt Software Associates, 1999. ISBN 0-921598-33-5

Smyth, Graham and Christine Stephenson. Computer Engineering: An Activity-Based Approach. Toronto: Holt Software Associates, 2000. ISBN 0-921598-36-X

Websites

Parallel port Central – http://www.lvr.com/parport.htm

Appendix 5.4.1

Interfacing a DC Motor (Turing)

Purpose: To control a DC motor through the computer.

Background: LEDs can be powered directly from the parallel port since they require very low voltages (generally in the 3Volt range). Refer to the Grade 10 Computer Engineering Profile for the exact activities and schematics to control one LED or eight LEDs. When larger voltages are required (e.g., a motor) a separate power supply is required. The power supply and the motor’s requirements should be in the same range (a 6 volt, 500 mA DC motor should have a 6 volt, 500 mA power supply). The motor can be turned off or on just as the LEDs can be turned off and on in the activities mentioned above. The difference is that the motors require a switch to control the separate power supply. Here, a transistor is used to do the switching. A transistor is an electronic switch that uses a lower voltage (here from the computer) to control a larger voltage (the separate power supply) that will actually run the motor. A more thorough explanation of transistors can be found in several of the reference books listed in this document. The computer should be isolated from the motor to minimize any possible damage to the computer due to mistakes in wiring.

Signals are sent through pin 2 on the parallel port to the base of the transistor. When the base is set high (a high on D0) the motor circuit is complete and the motor will turn on. When D0 is set low, the motor will turn off.

Code: This program will turn the motor on and when a key is pressed, the motor will turn off. This process can be repeated at the discretion of the user. (This code is written for Turing but can be adapted to Visual Basic).

var key: string (1)

var answer: string

% The program repeats until n is entered.

loop

% The motor is turned on

parallelput(1)

put “Hit any key to turn the motor off.”

getch (key)

% The motor is turned off.

parallelput(0)

put “continue y/n”

getch(answer)

exit when answer = “n”

end loop

Enrichment: The program listed above can be enhanced by developing a graphical user interface (GUI) to control the motor. Draw three boxes on the screen labelled “ON”, “OFF”, and “EXIT” along with a circle representing the motor and an arrow that is lit when the motor is on and outlined when the motor is off. When the “ON” box is clicked, the motor will turn on and the arrow will be lit. When the “OFF” is clicked, the motor will turn off and the arrow will be outlined. When “EXIT” is clicked, the motor will shut off and the program will exit.

Appendix 5.4.2

Interfacing LEDs (Visual Basic)

Introduction

Visual Basic uses the out command to send information to the parallel port. The out command contains two pieces of information: the port memory address and the data value, both in hexadecimal. In this lab you will investigate the storage of numbers in hexadecimal format, relate this to the parallel port, assemble components including LEDs that can be connected to a parallel port, and write a program that will control the LEDs.

Part 1 - Hexadecimal Representation of Numbers

Complete the worksheet entitled Hexadecimal Representation of Numbers

Part 2 - Identify the data pins of the parallel port

See www.doc.ic.ac.uk/~ih/doc/par/ Interfacing to the Parallel Port, and relate this diagram to the diagram of a byte.

Questions:

1.   What pin would be used to send out the signal 1?

2.   What pin would be used to send out the signal 2?

3.   What pins would be needed to send out the signal 3?

Part 3 - Determine the parallel port address of the computer used in the lab

Get this information from your teacher, a Visual Basic manual or Website referenced above, or complete the Parallel Port worksheet.

Part 4 - Assemble the interface

1.   Connect wires to pins 2 and 18 of the parallel port connector.

2.   Connect the wire from pin 2 to a resistor.

3.   Connect a wire from the resistor to the LED.

4.   Connect a wire from the LED to pin 18 (ground) of the parallel connector.

Part 5 - Write the program

1.   Open a new project file in Visual Basic.

2.   Add File inpout32.bas to the project.

3.   Add a frame and two option boxes.

4.   Add three image controls, lighton and lightoff twice from icons->misc of the standard Visual Basic 4.0 install.

 

 

Appendix 5.4.2  (Continued)

 

5.   Set the visible property of the two images on the right to false.

Private Sub optLEDOff_Click()

Out &h378, &h0

imgLED.Picture = imgHideOff.Picture

End Sub

6.   Click on the code window for optLEDOff and enter the following, given that 378 is the parallel port address and 0 is the data being sent to that port.

Private Sub optLEDOn_lick()

Out &h378, &h1

imgLED.Picture = imgHideOn.Picture

End Sub

7.   Click on the code window for optLEDOn and enter the following.

8.   Run the program. What do you observe?

 

Assignment

Add another LED to the project board and wire it up to data pin #2 and ground #19. If completed correctly the following results should occur.

Date Value

Program Statement

LED #2

LED #1

0

Out &h378, &h0

Off

Off

1

Out &h378, &h1

Off

On

2

Out &h378, &h2

On

Off

3

Out &h378, &h3

On

On

 

The following is a sample program form.

 

 

Appendix 5.4.3

Troubleshooting Interfacing Projects

An interfacing system consists of a computer, interface, and peripheral. The computer sends signals to the interface, often through the parallel port. The signals from parallel port on the computer are generated by the program you wrote. The interface is composed of electronic components that receive the signals from the computer and send them to the peripheral to be controlled. In the simple case where an LED is interfaced to a computer’s parallel port, the peripheral is the LED. The interface is the wire and resistor that connects the LED and computer. The computer program sends signals to the interface.

When an interfacing system does not function correctly, any of the above components could be a problem. The problem then is to narrow the problem. Some of the following suggestions should be considered.

·         Is the interface connected to the computer?

·         Is the interface connected to the peripheral?

·         If there is an external power supply (e.g., with motors), is it plugged in?

·         Start with the simplest program possible to test the hardware.

·         Develop the project step by step.

·         Do not write a large program and then test to see if it runs. Start by building the simplest version of the project first.

·         Learn how to measure voltage with a multi-meter (different instructions are included for each model).

·         Learn how to measure continuity with a multi-meter (different instructions are included for each model).

·         Check that there are no internal breaks in the wire (continuity test).

·         Check that the voltages are correct (voltage test).

·         Check that the proper signals are leaving the parallel port (use voltage test or insert LEDs temporarily).

·         Check that the proper signals are being received by the interface (use voltage test or insert LEDs temporarily).

·         Check that the proper signals are being sent by the interface (use voltage test).

·         Check that the proper signals are being received by the peripheral (use voltage test).

·         If the interface is mounted on a breadboard:

·         horizontal rows (at the top and the bottom of the bread board) are connected. Many breadboards are built with the horizontal rows split in the middle;

·         vertical connections are connected;

·         common (ground) connector for the parallel port and the interface are connected.

·         replace individual components, one at a time to determine faulty parts.

Summary

Start with the simplest program and the simplest interface that demonstrates the smallest part of the system. Build from there one-step at a time, testing each time.

Activity 5:  Impact of Computer Technology and Related Careers

Time:  180 minutes

Description

Students research and present findings on careers related to Computer Engineering. Students also explore the impact of computer technology at home and in the workplace. Examination of the moral and ethical issues in Computer Engineering reflect the teachings of the Catholic Church in areas such as social responsibility, human solidarity, and life and environmental issues.

Strand(s) & Learning Expectations

Strand(s):  Impact and Consequences

Overall Expectations

ICV.03 - describe issues relating to the ethical use of computers;

ICV.04 - identify computer engineering career paths.

Specific Expectations

IC1.02 - explain how computer technology affects daily life;

IC1.03 - describe issues that arise from the growing use of networked systems (e.g., complexity, compatibility, security);

IC1.05 - describe the computer expertise required for engineering and technology careers;

IC1.06 - identify post-secondary educational opportunities leading to careers in engineering and technology, as well as their entry requirements;

IC1.07 - use a variety of software applications to make class presentations on ethical issues in computing.

Ontario Catholic School Graduate Expectations

CGE3b - create, adapt, and evaluate new ideas in light of the common good;

CGE3f - examine, evaluate, and apply knowledge of interdependent systems (physical, political, ethical, socio-economic, and ecological) for the development of a just and compassionate society;

CGE4f - apply effective communication, decision-making, problem solving, and time and resource management skills;

CGE5a - work effectively as an interdependent team member.

Prior Knowledge & Skills

·         basic Internet/CD/Library/Resource Centre research methods

·         basic understanding of presentation techniques

Planning Notes

·         Organize career and computer technology reference material (See your student services/co-op teachers for assistance).

·         Review standards or guides for successful class presentations, research paper, or displays.

·         Develop a progress checklist sheet.

·         Review classroom behaviour expectations for possible class presentations.

Teaching/Learning Strategies

1.   Review the role of Christian values in modern society, including the ethical use of technology to improve life and develop stewardship of our world.

2.   Students are given the task of selecting a career to research and report on. Teachers initiate a discussion and development of a list with the class. Students propose the careers they will research. Teachers schedule group class presentations in a specified block of time at the end of the course as a “wrap-up” overview of Computer Engineering. It could also be set up where individual groups on a weekly basis do class presentations that relate to particular social, moral, or career aspects of Computer Engineering.

3.   Individuals or groups of students research their selected careers and include the topics of environmental consequences, technology developments, developments in computer hardware, security, safety, privacy, ethics, and computer skills required by employers.

4.   Students develop presentations, essays, and/or displays as required for their particular career topic. Presentations are given to the class.

Assessment & Evaluation of Student Achievement

·         Formative assessment of student progress.

·         Summative assessment of presentation that combines teacher and student feedback (Refer to Appendix 5.5.1 – Impact of Interfacing and Related Careers Rubric).

Accommodations

·         Assist with group formation to facilitate a peer tutoring or buddy system to promote an accepting and positive atmosphere and program enhancement or remediation.

·         Provide written material for students having difficulty processing auditory information.

·         Review new vocabulary and definitions prior to and during the lesson.

·         Make allowances for choice of topic or presentation methods. Individual students might feel strongly about an issue they would not feel comfortable presenting to the class but wish to submit as an essay.

·         Conference with individual students that experience organizational problems with large amounts of information.

·         Ensure understanding of tools used to assess/evaluate.

·         Provide print format and clear direction/expectations for presentation of final product.

Resources

Print

Newspapers and periodicals

Software

Current Ministry of Education word-processing and presentation software

Websites

Global Network of Environment and Technology – http://www.gnet.org

Environment Canada’s adaptive Computer Technology program – http://www.dinf.org/csun_98_125.htm

Career and Education – http://www.diversitycareers.com

Online Ethics Centre for Science and Engineering – http://www.onlineethics.org

Computer Professionals for Social Responsibility – http://www.cpsr.org/

Privacy International – http://www.privacyinternational.org/

Electronic Privacy Information Centre – http://www.epic.org/

Business Ethics Magazine – http://www.business-ethics.com/

Appendix 5.5.1

Impact of Computer Technology and Related Careers Rubric

Categories

Level 1
(50 - 59%)

Level 2
(60 - 69%)

Level 3
(70 - 79%)

Level 4
(80 – 100%)

Knowledge/Understanding

Overall knowledge of several engineering careers

- demonstrates limited knowledge of several engineering careers

- demonstrates moderate knowledge of several computer engineering careers

- demonstrates considerable knowledge of several computer engineering careers

- demonstrates a high degree of understanding of several computer engineering careers

Understanding of role of engineer in society

- demonstrates limited understanding of role of engineer in society

- demonstrates moderate understanding of role of engineer in society

- demonstrates considerable understanding of role of engineer in society

- demonstrates a high degree of understanding of the role of engineer in society

Understanding of presentation format

- demonstrates limited understanding of presentation format

- demonstrates moderate understanding of presentation format

- demonstrates considerable understanding of presentation format

- demonstrates a high degree of understanding of presentation format

Thinking/Inquiry

Evaluation of role of interfacing in engineering

- demonstrates limited competence in evaluating role of interfacing in engineering

- demonstrates moderate competence in evaluating role of interfacing in engineering

- demonstrates considerable competence in evaluating role of interfacing in engineering

- demonstrates a high degree of competence in evaluating role of interfacing in engineering

Analysis of career opportunities and form possible choices

- demonstrates limited analysis of career opportunity choices

- demonstrates moderate analysis of career opportunity choices

- demonstrates considerable analysis of career opportunity choices

- demonstrates a high degree of analysis of career opportunity choices

Communication

Communicating career observations and conclusions

- infrequently communicates career observations and conclusions

- sometimes communicates career observations and conclusions

- generally communicates career observations and conclusions

- effectively communicates career observations and conclusions

Communicating impact of computers on society

- infrequently communicates impact of computers on society

- sometimes communicates impact of computers on society

- generally communicates impact of computers on society

- effectively communicates impact of computers on society

Application

Applying interfacing to computer engineering careers

- infrequently applies interfacing to computer engineering careers

- sometimes applies interfacing to computer engineering careers

- generally applies interfacing to computer engineering careers

- effectively applies interfacing to computer engineering careers

Applying impact of programming to societal changes

- infrequently applies the impact of programming to societal changes

- sometimes applies the impact of programming to societal changes

- generally applies the impact of programming to societal changes

- effectively applies the impact of programming to societal changes

Note: A student whose achievement is below level 1 (50%) has not met the expectations for this assignment or activity.

 

 

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