THE STRUCTURE AND ADVANTAGES OF DIGITAL TRAINING SET FOR COMPUTER ENGINEERING

Transcription

1 THE STRUCTURE AND ADVANTAGES OF DIGITAL TRAINING SET FOR COMPUTER ENGINEERING GÜLAY TEZEL ŞİRZAT KAHRAMANLI Department Of Computer Engineering Selçuk University Department Of Computer Engineering, Faculty Of Engineering - Architecture Selçuk University 4075, Konya TURKIYE gtezel@selcuk.edu.tr sirzat@selcuk.edu.tr Abstract:-The knowledge provided in theoretical computer engineering education needs to be tested in laboratory which contributes to acquiring of specifications on tools, equipment and measurement methods. During the laboratory classes, using specifically produced experimental sets reduce cost and learning time developing the designing ability of students. The theoretical courses are supported with digital design and microprocessor courses in electronics and computer education, where the fundamentals of computer hardware and digital control technologies are provided. In the present study, the established Digital Training Set (DTS) and Microcontroller 803, and their advantages in experimentally teaching and learning of basic digital circuits design and principles of microprocessors in the Computer Engineering Department of Selcuk University are presented. Keywords:-Training set, integrated circuits, logical design, digital electronics. Introduction Digital computers occupy a prominent place in modern society. They have contributed to many scientific, industrial and commercial developments that would have been unattainable otherwise. They are used in home entertainment, medical treatment, weather forecast, space exploration, air traffic control, etc. the general purpose digital computer is the best-known example of digital systems. Digital electronics issue digital systems and design and continuously change and develop [,], although the basic principles of computers and digital design remain the same. Learning of theoretical digital electronics without practice does not provide sufficiently permanent understanding and knowledge. To this purpose, special-purpose training sets are preferred in education. Therefore, a general purpose Digital Training Set (DTS) and microcontroller 803 Experiment Set are designed and developed for the courses of digital electronics and microprocessors and the other hardware projects for the Computerelectronics students. The Advantages of Digital Training Set Using special-purpose training test set has some advantages in the sense of practical and theoretical for both students and instructors. The ISSN: ISBN:

2 advantages of this experimental set are explained followingly.. The Cost Advantages Generally, either serially produced test sets are used or experiments are performed on breadboards in computer-electronics training. These serially produced test sets are much more expensive, and in case of damage, technical support can not be fast enough. The students mostly do the experiments independently, therefore, they are subject to frequent problems on the set of units or uncontrollable failures. Some other problems may occur for students or laboratory facilities in direct working on the experimental bread-board in the absence of training set with the start of the circuit design application, where the integrated circuits (IC) and other materials are directly given to the students. Eventually this will result in increase in refuse and errors during the experiment. Students who do not carefully handle the IC s structures can make wrong circuit connections producing a complete set of waste in the end of experiment. Training set prevents materials refuse. The Application Advantages In the experimental applications, students must benefit IC s datasheets even when there isn t a pre-set training set. They usually do not have catalog specifications of IC s from datasheets, therefore the connection of the IC s, input and output units are frequently mishandled at the first time they place the integrate on the board. As a result, the electronic equipments are damaged and valuable time is spent during the application. However the rate of misuse in experiments can be minimized with training sets as the names of the IC s pin connectors and some IC symbols (logical gates, flip-flops etc..) are printed with serigraphy on the upper surface of DTS. Furthermore, the sources of DTS such as power supply, synchronized signal source and pulse generator facilitate the installation of circuits. The design of a counter in an experimental application requires not only a counter ICs but some additional hardware such as power supply, switches for input, pulse generator for clock, display or LED for output are also required. In the counter experiment the students have to construct these additional hardware equipments if there is no training set such as DTS. Although the aim of the experiment is to learn how to construct a counter, they have to spent excessive time and effort for the construction of additional circuits and equipments rendering the application of the experiment highly complicated. The use of training sets facilitates the experiment for both instructors and students in the combined circuit design and construction. 3 Technical Properties of DTS The design of DTS is improved after careful consideration of current digital design course curriculums in electrical and computer science education. The purpose of DTS is to integrate the properties of logical expressions into integratedcircuit and provide the use of ICs for digital design. The improved applied flexible design method, DTS can be used with the microprocessor system to develop more complex studies. DTS of the printed circuit board was drawn using ORCAD program on a double-sided plaque at dimensions of 95x50 mm. Symbols, names and figures of ICs and connectors were printed with serigraphy on the upper surface prior to placing the equipment (Fig. and Fig. ) which facilitates the understanding of the applied experiment and prevents confusion on the set attracting the student s attention to the pin structure of IC. There are twenty-eight sections about different objectives and tasks on DTS (Fig. Fig. ). Four of these sections are input and output units (switch, display and LED), one applicationboard (bread-board) and other 3 sections are ICs for different experimental purposes and tasks. These integrated circuits can be connected to each other via a cable only mm in diameter. Connectors are added to the input and output of ICs. The bread-board is used as the application board on DTS when additional ICs are needed on it. This increases the utilization of DTS in a number of experimental studies. Minimizing the power loss during the design is one of the most important goals. t all the ICs on the set receive voltage (Vcc=+5 Volt), but the ones under experimentation. A fixed +5 V power supply can be connected to ICs with a wire ISSN: ISBN:

3 by the user in the experiments, and so, unnecessary electrical power consumption is prevented. 4 The Structure of DTS DTS will be examined in six sections and general specifications are described in the following subsections. 4. Power Supplies There is one short-circuit protected power supply on DTS. It provides 5V and adjustable V power supply to ICs on DTS. Adjustable voltage source is located on the upper left corner of the set and constant voltage source is on the upper right corner of the set. Adjustable voltage source has been added especially for ADC (Analog Digital Converter), DAC (Digital Analog Converter) and externally designed circuits. 4. Synchronized Signal Generator Synchronized signal generator described as Astable Multivibrator circuit is designed using NE555 Timer integrated circuits. Signal generator has been designed consisting of three stages using three capacitors ( F, nf and 00pF). The rising and falling time of pulse signal is around only 0 s and this property is important for many circuits requiring fast switching time. Frequency range is between Hz to 8MHz. Voltage level of square wave taken from the output is 5V [3, 4]. 4.3 Pulse Generator This circuit produces only a single pulse when it is triggered. IC 743 Monostable Multivibrator is used in its design. Two different pulses can be obtained from the output of IC 743. One of them is on the level of Logic (positive level) and the other one is on the level of Logic 0 (negative level). The pulse duration of the Logic or Logic 0 depends on external rezistor (Rx) and capacitor (Cx) value connected to the IC 743. It is approximately 5 nanoseconds for DTS. Also multi-vibrator has a very fast rise and fall times [3]. 4.4 The Section of Switching Because the size of working area of DTS is large, switches have been distributed to three different regions. Thus, 8 bit switches are available in three different areas. If the switch is in the OFF position, the value of its output named as logic 0, is on 0 Voltage level. ON position in the output called as logic has a value of +5 Voltage level. 4.5 The Section of Indicator Indicator section is an area of DTS for obtaining and observing the output of the design and implementation of the circuits. It consists of two different sections. In the first indicator s section, there are two groups of LEDs because of the large surface area of DTS. Very long cable or more complex circuits is prevented. Every group has eight LEDs on DTS. Connectors are placed on the inputs of all LEDs. If the level of information on the input s connectors of LED is Logic, LED lights, otherwise it doesn t light. The second part of this section consists of display indicators. There are two displays and two driver ICs to drive them. The number of input of driver ICs is four bits. This four-bit binary code is decoded with 7447 driver IC into display s code. Thus, according to input information codes appear on the display. 4.6 Working Area Working area is a section which contains ICs for experimental studies. The ICs in this section are grouped separately as sequential logic and combinational logic integrated. ICs located on the Working area are listed in Table. In addition, Fig. represents general overview of DTS and also Fig. shows the top view of DTS [5, 6]. 5 Results Despite the rapidly growing computer and electronics technology, the principles of digital design of ICs and the computer hardware-related concepts remain the same. Digital design courses are the fundamental courses in electronics and computer science education. Therefore, necessary tools for efficient learning is important. But, the theoretical knowledge needs to be supported with experimental training courses. ISSN: ISBN:

4 The students can learn properties of ICs, digital electronics equipments and measurement methods more efficiently in the laboratory. The easiest method of working in the digital electronics laboratory is using experimental sets. Specifically produced experiment test sets reduce learning time and cost in the laboratory classes. Also training sets develop the designing ability of students. A general purpose Digital Training Set (DTS) is described for these reasons. With this training set (DTS), students, teachers or people interested in digital electronics can perform their experiments in a less complicated method where required additional equipments such as signal generators, switches, display and LED are made ready on DTS during the application of a logical design. This provides savings in time and money. The symbol of ICs or names of pins of ICs placed on DTS reduce the risk of incorrect connections and helps the user s performance. As DTS is designed and developed for students experiments, it is easy to intervene quickly in case of any failure/error and develop the system. When both financial and technical advantages are considered, applied DTS will be useful for learners dealing with digital design and computer hardware. References [] Mano. M.M.. Digital Design. nd ed. Prentice Hall. Inc., 99. [] Mano, M.M., Sayısal Tasarım. Prentice Hall. Inc. MEB,994 [3] Sprorck, E., Logic Databook. Volume -. National Seminconductor Corporation, 984. [4] Kahramanlı, Ş., Özcan, M., Lojik Tasarımın Temelleri (Fundamentals of Logical Design). bel Press, 000 (In Turkish). [5] Texas Instruments, HC/HCT Logic Data Book. Custom Printing Company, 997. [6] Tezel, G., Digital Training Set. Masters Thesis, Institute of Natural and Applied Science, Selcuk University, Konya, Turkey, 00. Acknowledgements This work is financially supported by the Coordinating Office of Scientific Research Projects in Selcuk University Fig.. General view of DTS ISSN: ISBN:

5 Fig.. Top view of DTS obatained with the method of serigraphy Table : The names of ICs in the working area INTEGRATED CIRCUITS Part Part Description Quantity Description Quantity 7408 Quad -Input AND Dual x Decoder/Demultiplexer 743 Quad -Input OR 746 Quad 3-State Buffer Six Inverter (NOT) Octal 3-State Buffer Quad -Input NAND 8-Bit 3-State Transparent Latch Quad -Input NOR Universal Shift Register Quad -Input XOR Up/Down Decade Counter Dual D-Type Flip- Synchronous Up/Down Flops 4-Bit Binary Counter 8 74 Dual J-K Flip- Flops ALU (Arithmetic/Logic Unit) Quadruple R-S DAC Digital Analog 9 Latches 0808 Converter (DAC) Dual 4x Multiplexer 0 ADC Analog Digital 0808 Converter (ADC) ISSN: ISBN: