welcome to engsci 232 sc computer systems lecture 1

ENGSCI 232SC Lecture 1 1

Welcome toENGSCI 232 SC

Computer Systems

Lecture 1

Department of Engineering Science

The University of Auckland


Course Objectives : 1

• Gain an understanding of digital circuit components, data representation, and some important aspects of computer architecture including memory and input/output.


Course Objectives: 2

• Develop skills and confidence in using laboratory equipment and the design and implementation of hardware/software interfaces, in particular the use of the PC parallel port to communicate with external digital logic circuits via Visual Basic program code.


Lecture Topics

• 1. Introductory Concepts• 2. Digital Gates• 3. Combinatory Circuits• 4. Synchronous Circuits• 5. Data Representation• 6. Instruction Sets• 7. Memory• 8. Input/Output• 9. Architecture


Laboratories

• ENGSCI232 laboratories will begin in Week 2, Wednesdays 9-11, in 439.433. Completion of lab work is compulsory. Failure to complete will lead to a DNC (Did Not Complete) grade.

• Laboratory tasks and associated assignment questions will contribute 40% to the final mark.

• ENGSCI272 labs will be organised by Dr Nielsen.


Exam

• A 2 hour written examination will contribute 60% to the final mark, with the condition that the final mark cannot exceed the exam mark by more than 10%.

• No calculators permitted in the exam.


Resources and Results

• Coursework results, announcements etc will appear on the course website

• http://www.esc.auckland.ac.nz/teaching/engsci232sc


Course Staff

• Jim Greenslade – Lecturer, and Course Organiser

Department of Engineering Science

Room 439.233

ext 88390

[email protected]

• Dr Mason will lecture from Week 7 onwards.


Questions

• Any questions about Course Organisation?


Introductory Concepts

• The term “digital” occurs throughout most areas of everyday life (not only computers but home appliances, phones, transportation, entertainment, medical science and practice etc)

• We will first cover some of the underlying concepts and terminology on which to build a good understanding of this area.


Numerical Representation

• Quantities are measured and represented in on of two forms:

• 1. Analogue: a quantity represented by a voltage, current or meter movement proportional to the value of the quantity. Eg mercury thermometer, audio mic.

• 2. Digital: quantities represented by digits rather then proportional quantities.


• eg Digital watch

• So, analogue=continuous

• Digital = discrete (step by step) and hence no ambiguity of interpretation.

• Categorise the following:

• Ten-position switch, current flowing from an electrical outlet, sand grains on the beach, car speedometer.


Digital and Analogue Systems

• A digital system is a combination of devices which manipulate logical information in digital form (ie discrete values). May be mechanical, magnetic or pneumatic but most often electrical.

• Analogue system contains devices which manipulate quantities that vary over a continuous range eg simple dimmer switch, volume output to a radio speaker.


Advantages of Digital Techniques

• Easier to design

• Information storage is easier

• Accuracy and precision are greater

• Operation can be programmed

• Digital circuits are less affected by noise

• More digital circuitry can be fabricated on IC chips


Limitations of Digital Techniques

• The real world is analogue !!• Often we need to go through conversion steps.• Analogue-to-Digital converter (ADC)• Digital-to-Analogue converter (DAC)• eg music CD. Starts as analogue sound,

digitised onto CD, played in CD player, converted back to analogue to feed speakers and hence to your “analogue ear”.


Decimal Number Systems

• Remember that the decimal number system comprises 10 digits. When representing a number, the least significant digit is on the right and is weighted as 10^0, the next digit being weighted 10^1 etc. In counting, when we reach 9 we need to reset the value of the current position back to 0 and carry a 1 through to the next (more significant) position.


Binary Number System

• Very similar except we are now working in Base 2 so have only 2 digits (0,1).

• Least significant digit is 2^0, then moving right to left the weighting increases 2^1, 2^2 etc

• When counting, after reaching 1 we must reset back to zero and carry 1 through to the next (more significant) place.


Revision

• What is the equivalent of the binary number 1101011 ?

• What is the next binary number after this number (ie add 1) ?

• How many decimal numbers can be represented using 7 binary bits ?


Digital Circuits

• Comprise electronic devices which will respond predictably to input voltages which lie within an allowable “zero” range and allowable “one” range. Subsequent outputs will also lie within one of these two ranges.

• Systems may use different voltage levels eg a 1 may be represented by 3.7 volts or 5 volts depending on the system.


Logic Circuits

• Basic digital components are really just switches (individual transistors).

• To be of use they are configured to perform “logical” operations.

• We will explore and utilise chips which perform such logical tasks as:

• AND, OR, NOT, XOR


Integrated Circuits (ICs)

• Various IC technology is available:

• TTL (transistor-transistor logic) uses the bipolar transistor as its main circuit element

• CMOS (complementary metal-oxide-semiconductor) uses the enhanced-mode MOSFET as its principal element.


Parallel and Serial Transmission

• Computer are constantly transferring information. This may be over sub-millimeter ranges within ICs, millimeter range between functional units within the computer, meter range between a computer and locally attached peripheral devices (scanners printers etc) or long range between computers world-wide.


Parallel

• A local printer may be connected using a parallel cable in which case all 8 bits of a character can be transmitted simultaneously (each bits travels on a separate wire within the cable). This has the benefit of speed but adds considerable complexity and is not practical for longer distance communication.


Serial

• A serial connection normally involves a single wire being used to send a stream of bits (sequentially). This is inherently slower but is easier and cheaper to implement and to use over any distance.


Computer Memory

• Often the main memory (RAM) of a computer uses ICs containing millions of “latches” or “flip-flops”. These are capable of being in only one of 2 states (on or off, 1 or 0) and can change state very quickly when new data is applied to the data bus and “latched” into a particular memory address (or location).


Major Parts of a Digital Computer

• Input Unit – through which data is feed to the computer.

• Memory Unit – for storage of instructions and data.

• Control Unit – to interpret instructions and signal all other units to achieve execution.

• ALU – Arithmetic and Logical calculations and decision making.

• Output Unit – displays or prints processed data.


Next Week

• We will look in more detail at Digital Logic Gates.

• In the lab this week you will get an introduction to some logic gates and how to connect these together.

welcome to engsci 232 sc computer systems lecture 1

Documents

sc lecture

lecture topics

digital watchso

digital form

digital gates3

course objectives

course organisation

course websitehttp