The Meyer Lectures on Digital Systems


Module 2: Combinational Logic Circuits

Objectives and Outcomes

Slectures by Robert Wayner

© 2013


Learning Outcome

an ability to analyze and design combinational logic circuits

Learning Objectives

  1. identify minterms (product terms) and maxterms (sum terms)
  2. list the standard forms for expressing a logic function and give an example of each: sum-of-products (SoP), product-of-sums (PoS), ON set, OFF set
  3. analyze the functional behavior of a logic circuit by constructing a truth table that lists the relationship between input variable combinations and the output variable
  4. transform a logic circuit from one set of symbols to another through graphical application of DeMorgan’s Law
  5. realize a combinational function directly using basic gates (NOT, AND, OR, NAND, NOR)
  6. draw a Karnaugh Map (“K-map”) for a 2-, 3-, 4-, or 5-variable logic function
  7. list the assumptions underlying function minimization
  8. identify the prime implicants, essential prime implicants, and non-essential prime implicants of a function depicted on a K-map
  9. use a K-map to minimize a logic function (including those that are incompletely specified) and express it in either minimal SoP or PoS form
  10. use a K-map to convert a function from one standard form to another
  11. calculate and compare the cost (based on the total number of gate inputs plus the number of gate outputs) of minimal SoP and PoS realizations of a given function
  12. realize a function depicted on a K-map as a two-level NAND circuit, two-level NOR circuit, or as an opendrain NAND/wired-AND circuit
  13. define and identify static-0, static-1, and dynamic hazards
  14. describe how a static hazard can be eliminated by including consensus terms
  15. describe a circuit that takes advantage of the existence of hazards and analyze its behavior
  16. draw a timing chart that depicts the input-output relationship of a combinational circuit
  17. identify properties of XOR/XNOR functions
  18. simplify an otherwise non-minimizable function by expressing it in terms of XOR/XNOR operators
  19. describe the genesis of programmable logic devices
  20. list the differences between complex programmable logic devices (CPLDs) and field programmable gate arrays (FPGAs) and describe the basic organization of each
  21. list the basic features and capabilities of a hardware description language (HDL)
  22. list the structural components of an ABEL program
  23. identify operators and keywords used to create ABEL programs
  24. write equations using ABEL syntax
  25. define functional behavior using the truth_table operator in ABEL
  26. define the function of a decoder and describe how it can be use as a combinational logic building block
  27. illustrate how a decoder can be used to realize an arbitrary Boolean function
  28. define the function of an encoder and describe how it can be use as a combinational logic building block
  29. discuss why the inputs of an encoder typically need to be prioritized
  30. define the function of a multiplexer and describe how it can be use as a combinational logic building block
  31. illustrate how a multiplexer can be used to realize an arbitrary Boolean function

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