1. Acknowledgement: Overheads adapted from those provided by the authors of the textbook Logic Circuits Mehmet Can Vuran, Instructor University of Nebraska-Lincoln

2. CSCE 230 - Computer Organization2

3. 3

4.  Programmable  Software ▪ Typically, use single-board microcontrollers to implement the logic by a program  Programmable logic devices (PLDs) and field programmable gate arrays (FPGAs) ▪ Devices in which the logic elements and the interconnect (wiring) can be modified by programming. ▪ Ideal for rapid prototyping and low-volume applications.  ROMs  Custom Designs  How Intel designs microprocessors  Cost-effective only for high-volume parts CSCE 230 - Computer Organization4

5.  Operate on binary variables that assume one of two distinct values, usually called 0 and 1  Implement functions of logic variables  Circuits have inputs and outputs  Circuits are implemented using electronic logic gates

6. AND OR NOT B A B A C B A C 6CSCE 230 - Computer Organization

7. ABC 00 01 10 11 B A B A C B A C AND 7CSCE 230 - Computer Organization

8. ABC 000 010 100 111 B A B A C B A C AND 8CSCE 230 - Computer Organization

9. ABC 000 010 100 111 B A B A C B A C ABC 00 01 10 11 ANDOR 9CSCE 230 - Computer Organization

10. ABC 000 010 100 111 B A B A C B A C ABC 000 011 101 111 ANDOR 10CSCE 230 - Computer Organization

11. NOT ABC 000 010 100 111 B A B A C B A C ABC 000 011 101 111 AB 0 1 ANDOR 11CSCE 230 - Computer Organization

12. NOT ABC 000 010 100 111 B A B A C B A C ABC 000 011 101 111 AB 01 10 ANDOR 12CSCE 230 - Computer Organization

13. ABXOR 00 01 10 11 13CSCE 230 - Computer Organization

14. ABXOR 000 011 101 110 14CSCE 230 - Computer Organization

15. Light switch example

18.  Operate on binary variables that assume one of two distinct values, usually called 0 and 1  Why?  Let’s back up…

21. ABNAND 001 011 101 110 Not AND  NAND

22. ABNAND 001 011 101 110

23. NOT AB 01 10

24. AND ABC 000 010 100 111

25. OR ABC 000 011 101 111

26. ABC 000 011 101 111

27. XOR ABC 000 011 101 110

28. NOR ABC 001 010 100 110

29. XNOR ABC 001 010 100 111

30. ABXOR 000 011 101 110

32.  Synthesis is the process of designing and implementing a logic circuit defined by its functional specification.  The expression for f in the previous circuit is said to be in a sum-of-products form  OR and AND operations are sometimes called the sum and product functions.

39.  Show a logic equation for the three functions shown in the following truth table: 39CSCE 230 - Computer Organization

40.  As illustrated in the previous example, a logic function can be implemented with circuits of different complexities.  It is useful to minimize a logic expression to reduce the cost of the synthesized circuit.

41. 41

43. Four-variable Karnaugh maps

44. Using don’t cares

48. 48

50. NMOS Transistor

54. PMOS Transistor

62.  Cannot directly connect logic gates  May damage the circuits in certain input combinations  May not need ALL the gates together  If a gate is not SELECTED, it should not provide 1 or 0  Need a third output – Z (high impedance) 62

64.  HW 3 – Chapter 3  Assign Friday, Sept. 27 th  Due Wednesday, Oct. 9 th  Test 1 – Chapters 1-2  Monday, Oct. 7 th (50 min)  Quiz 3 – Chapter 3  Friday, Oct. 11 th (15 min) 64