Course Number: COMP 1213 Course Title: Logic Design

1. Course Number: COMP 1213 Course Title: Logic Design Instructor: Dr. Ali ElkateebText Book:Contemporary Logic Design byRandy H. Katz

2. Course Objectives To learn: The combinational logic design. The programmable logic design. The sequential circuit design. Computer Organization.

3. 1. Terms Design: Convert the problem to a hardware blocks. Parts Selection: Select the parts required by the design. Schematic Capture: Enter the design in the computer. Simulation: Check the operation of the design. Mapping: Map the design to a certain chip. Debugging: Check whether the design is error free. Implementation: Assembly all the design blocks. Design Steps

4. 2. Design Flow: Using LogicWork Schematic Capture Debugging Design Simulation

5. Design Representation Start 1. Functional description Green: On Yellow: Off Red: Off flow charts, program fragments after 45 seconds Green: Off Yellow:On Red: Off 2. Structural description after 2 seconds complex components decomposed into a less complex components Green: Off Yellow: Off Red: On after 45 seconds 3. Physical description design is represented in terms of most primitive building blocks, e. g., logic gates or transistors Functional Description Of One Traffic Light Signal

6. Design Methodology Top Down Design: Complex functions replaced by more primitive functions Bottom Up Design: Primitives composed to build more and more complex assemblies

7. The Process of Design Bottom Up Assembly Building Primitives composed to build more and more complex assemblies e.g., a group of rooms form a floor e.g., a group of floors form a bldg. a group of transistors form a gate a group of gates form an addition circuit addition circuits plus storage circuits form a processor datapath Floor Rooms

8. The Process of Design: Debugging the System What Can Go Wrong • Design Flaws Implementation does not meet functional specification Logic design is incorrect (wrong function implemented) • Implementation Flaws Individual modules function correctly but their compositions do not Misunderstanding of interface and timing behavior Wiring mistakes, Electrical mistakes • Component Flaws Every thing is correct. Nevertheless, the design still not working! Not all hardware components are guaranteed to work! E.g., burnt out component

9. • Improving the testability of the design • Formulating a testing plan. • Isolating portions of the implementation for testing • Effective use of laboratory instruments for troubleshooting The Process of Design Debugging via Simulation Debugging Skills:

10. T ime Digital Hardware Systems Digital Systems Digital Vs. Analog Waveforms +5 1 0 1 0 Digital: only assumes discrete values Analog: values vary over a broad range continuously

11. Digital Hardware Systems Advantages of Digital Systems Analog systems: slight error in input yields large error in output Digital systems more accurate and reliable Computers use digital circuits internally Interface circuits (i.e., sensors) often analog

12. Digital Hardware Systems Physical electronic components are continuous, not discrete! Transition from logic 1 to logic 0 does not take place instantaneously in real digital systems

13. Digital Hardware Systems • Integrated circuit technology: • Small Scale Integration (SSI) • Medium Scale Integration (MSI) • Large Scale Integration (LSI) • Very Large Scale Integration (VLSI) Main technologies: MOS: Metal-Oxide-Silicon Bipolar Transistor-Transistor Logic Emitter Coupled Logic

14. Digital Hardware Systems MOS Technology Transistor basic electrical switch three terminal switch: gate, source, drain voltage between gate and source exceeds threshold switch is conducting or "closed" electrons flow between source and drain when voltage is removed, the switch is "open" or non-conducting connection between source and drain is broken