1 / 34

COE 202: Digital Logic Design Sequential Circuits Part 2

Dr. Ahmad Almulhem Email: ahmadsm AT kfupm Phone: 860-7554 Office: 22-324. COE 202: Digital Logic Design Sequential Circuits Part 2. Objectives. Analysis of Synchronous Sequential Circuits Procedure Examples. Analysis of Combinational vs Sequential Circuits. Combinational :

gwenllian-baker
Download Presentation

COE 202: Digital Logic Design Sequential Circuits Part 2

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Dr. Ahmad Almulhem Email: ahmadsm AT kfupm Phone: 860-7554 Office: 22-324 Ahmad Almulhem, KFUPM 2009 COE 202: Digital Logic DesignSequential CircuitsPart 2

  2. Ahmad Almulhem, KFUPM 2009 Objectives • Analysis of Synchronous Sequential Circuits • Procedure • Examples

  3. Ahmad Almulhem, KFUPM 2009 Analysis of Combinational vs Sequential Circuits • Combinational : • Boolean Equations • Truth Table • Output as a function of inputs • Sequential : • State Equations • State Table • State Diagram • Output as a function of input and current state • Next state as a function of inputs and current state.

  4. Ahmad Almulhem, KFUPM 2009 Analysis of Sequential Circuits • Steps: • Obtain state equations • FF input equations • Output equations • Fill the state table • Put all combinations of inputs and current states • Fill the next state and output • Draw the state diagram

  5. Ahmad Almulhem, KFUPM 2009 State Table 4 sections

  6. Ahmad Almulhem, KFUPM 2009 State Table (2-D Form) 1

  7. Ahmad Almulhem, KFUPM 2009 State Diagram • The state diagram is a graphical representation of a state table (provides same information) • Circles are states (FFs), Arrows are transitions between states • Labels of arrows represent inputs and outputs

  8. Ahmad Almulhem, KFUPM 2009 Example 1 • Analyze this circuit? • Is this a sequential circuit? Why? • How many inputs? • How many outputs? • How many states? • What type of memory?

  9. Ahmad Almulhem, KFUPM 2009 Example 1 (cont.) D Flip Flop (review) Characteristic Tables and Equations Q(t+1) = D

  10. Ahmad Almulhem, KFUPM 2009 Example 1 (cont.)

  11. Ahmad Almulhem, KFUPM 2009 Example 1 (cont.) • State equations: • DA = AX + BX • DB = A’ X • Y = (A + B) X’

  12. Ahmad Almulhem, KFUPM 2009 Example 1 (cont.) • State equations: • DA = AX + BX • DB = A’ X • Y = (A + B) X’ • State table:

  13. Ahmad Almulhem, KFUPM 2009 Example 1 (cont.) • State equations: • DA = AX + BX • DB = A’ X • Y = (A + B) X’ • State table (2D):

  14. Ahmad Almulhem, KFUPM 2009 Example 1 (cont.) • State equations: • DA = AX + BX • DB = A’ X • Y = (A + B) X’ • State table: State diagram:

  15. Ahmad Almulhem, KFUPM 2009 Example 2 • Analyze this circuit. • What about the output? • This circuit is an example of a Moore machine (output depends only on current state) • Mealy machines is the other type (output depends on inputs and current states)

  16. Ahmad Almulhem, KFUPM 2009 Example 2 (cont.) • Equation: • DA = A  X  Y

  17. Ahmad Almulhem, KFUPM 2009 Example 2 (cont.) • Equation: • DA = A  X  Y

  18. Ahmad Almulhem, KFUPM 2009 Example 3 • Analyze this circuit? • Is this a sequential circuit? Why? • How many inputs? • How many outputs? • How many states? • What type of memory?

  19. Ahmad Almulhem, KFUPM 2009 Example 3 (cont.) JK Flip Flop (review) Characteristic Tables and Equations Q(t+1) = JQ’ + K’Q

  20. Ahmad Almulhem, KFUPM 2009 Example 3 (cont.)

  21. Ahmad Almulhem, KFUPM 2009 Example 3 (cont.) • State equations: • JA = B, KA = B X’ • JB = X’, KB = A  X • by substitution:A = JAA’ + KA’A = A’ B + A B’ + A XB = B’ X’ + A B X + A’ B X’

  22. Ahmad Almulhem, KFUPM 2009 Example 3 (cont.) • State equations: • JA = B, KA = B X’ • JB = X’, KB = A  X • by substitution:A = JAA’ + KA’A = A’ B + A B’ + A XB = B’ X’ + A B X + A’ B X’

  23. Ahmad Almulhem, KFUPM 2009 Example 3 (cont.) • State equations: • JA = B, KA = B X’ • JB = X’, KB = A  X • by substitution:A = JAA’ + KA’A = A’ B + A B’ + A XB = B’ X’ + A B X + A’ B X’

  24. Ahmad Almulhem, KFUPM 2009 Example 4

  25. Ahmad Almulhem, KFUPM 2009 Example 4 (cont.) State equations: JA = BX’ KA = BX’ + B’X DB = X Y = X’AB by substitution: A(t+1) = JAA’ + KA’A

  26. Ahmad Almulhem, KFUPM 2009 Example 4 (cont.) State equations: JA = BX’ KA = BX’ + B’X DB = X Y = X’AB by substitution: A(t+1) = JAA’ + KA’A

  27. Ahmad Almulhem, KFUPM 2009 Example 5 • Analyze this circuit? • Is this a sequential circuit? Why? • How many inputs? • How many outputs? • How many states? • What type of memory?

  28. Ahmad Almulhem, KFUPM 2009 Example 5 (cont.) T Flip Flop (review) Characteristic Tables and Equations Q(t+1) = TQ’ + T’Q

  29. Ahmad Almulhem, KFUPM 2009 Example 5 (cont.)

  30. Ahmad Almulhem, KFUPM 2009 Example 5 (cont.) State equations: TA = BX TB = X Y = AB by substitution: A(t+1) = TAA’ + TA’A

  31. Ahmad Almulhem, KFUPM 2009 Example 5 (cont.) State equations: TA = BX TB = X Y = AB by substitution: A(t+1) = TAA’ + TA’A

  32. Ahmad Almulhem, KFUPM 2009 Example 5 (cont.) State equations: TA = BX TB = X Y = AB by substitution: A(t+1) = TAA’ + TA’A The output depends only on current state. This is a Moore machine What does this circuit do?

  33. Ahmad Almulhem, KFUPM 2009 Mealy vs Moore Finite State Machine (FSM) • Mealy FSM: • Output depends on current state and input • Output is not synchronized with the clock • Moore FSM: • Output depends on current state only

  34. Ahmad Almulhem, KFUPM 2009 Summary • To analyze a sequential circuit: • Obtain state equations • FF input equations • Output equations • Fill the state table • Put all combinations of inputs and current states • Fill the next state and output • For the next state use characteristic table/equation • Draw the state diagram • Two types of synchronous sequential circuits (Mealy and Moore)

More Related