CS 231 Fall 2005 Review SessionToday’s topics1. There is a combinatorial circuit, a flip-flop and a latch with control. Which is which?PowerPoint Presentation2. Given the following circuit and initial input values… Gate delay = 1 nsSlide 6Slide 7Slide 8Slide 9Slide 10Slide 11Slide 12Slide 13Slide 14Slide 15Slide 16Slide 17Slide 18Slide 19Slide 20Slide 21Slide 22Slide 232. Sequential Circuit DesignSlide 25Slide 26Slide 27Slide 28Slide 29Slide 30Slide 31Slide 32Slide 33CS 231Fall 2005Review SessionFriday, Oct 21by Celal ZiftciToday’s topicsHow to distinguish between different kinds of circuits? (Combinatorial, Latch, Flip-flop)How to find the timing diagram of a given circuit (with gate delays)?How to design a sequential circuit, for a given problem definition?1. There is a combinatorial circuit, a flip-flop and a latch with control. Which is which?2. Given the following circuit and initial input values…Gate delay = 1 ns2. Sequential Circuit DesignProblem definition: Implement a circuit which outputs 1 only if the # 1’s in the input string is a multiple of 4.Ex:Input 0 1 0 0 1 1 1 0 0 1 Output 1 0 0 0 0 0 1 1 1 0Observation:We can rewrite the problem as follows:Output 1 when: (X % 4) = 0(X is the number of 1’s so far).So we don’t need to remember the whole string. We only need to remember (X % 4).We have 4 possibilities: 0, 1, 2, 3Using the state diagram, we can construct our state table…After this point, we can draw K-maps for J1, K1, J0, K0 and output, and we are done!All for today.If you have any questions, come to any TA office
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