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    Unit 3 Flip Flop Notes

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    vmspraneeth
    Unit 3 Flip Flop Notes

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    Unit 3 Flip Flop Notes

    Uploaded by

    vmspraneeth
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    Unit 3 Flip Flop Notes

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    Unit 3 Flip Flop Notes

    Copyright:

    © All Rights Reserved
    Download as PDF or read online from Scribd
    Download as pdf
    2K views23 pages

    Unit 3 Flip Flop Notes

    Uploaded by

    vmspraneeth
    Unit 3 Flip Flop Notes

    Copyright:

    © All Rights Reserved
    Download as PDF or read online from Scribd
    Download as pdf
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    Unit 3 FlipFlops Notes UNIT-III(COUNTERS AND REGISTERS) RS, JK, JK Master-Slave - D, T flip — flops - level triggering and edge triggering - excitation tables - asynchronous, synchronous counters - modulus counters — Johnson counter —ring counter — timing waveforms - counter applications — registers — shift register - universal shift register - sequential Logic Design — Basic models of sequential machines - concept of state table — state diagram — state reduction through partitioning - implementation of sequential Circuits - Introduction to asynchronous sequential logic design. Prepared by M. Raja, CSE/KLU Unit 3 FlipFlops Notes SEQUENTIAL CIRCUITS Digital electronics is classified into combinational logic and sequential logic. Combinational logic output depends on the present inputs levels, whereas sequential logic output not only depends on the input levels, but also stored levels (previous output history). Combinational Circuits Combinational = [> n inputs — moutpus . circuit i Fig. Block Diagram of Combinational Circuit Sequential Cireui Primary inputs Pri ts se! Combinational Logie Cireuit {secondary outputs Memory Elements, The memory elements are devices capable of storing binary info. The binary info stored in the memory elements at any given time defines the state of the sequential circuit. The input and the present state of the memory element determine the output. Memory elements next state is also a function of external inputs and present state. A sequential circuit is specified by a time sequence of inputs, outputs, and internal states. There are two types of sequential circuits. Their classification depends on the timing of their signals: “ Synchronous sequential circuits 4 Asynchronous sequential circuits Asynchronous sequential cireuit This is a system whose outputs depend upon the order in which its input variables change and can be affected at any instant of time. Prepared by M. Raja, CSE/KLU Unit 3 FlipFlops Notes + Outputs {2) Thing sagem of eck puss Synchronous sequential circuits This type of system uses storage elements called flip-flops that are employed to change their binary value only at diserete instants of time, Synchronous sequential circuits use logic gates and flip-flop storage devices. Sequential circuits have a clock signal as one of their inputs. All state transitions in such circuits occur only when the clock value is either 0 or 1 or happen at the rising or falling edges of the clock depending on the type of memory elements used in the circuit. Synchronization is achieved by a timing device called a clock pulse generator. Clock pulses are distributed throughout the system in such a way that the flip-flops are affected only with the arrival of the synchronization pulse. Synchronous sequential circuits that use clock pulses in the inputs are called clocked-sequential circuits. ‘Combinationat Ca ‘Clock pulses (b) Timing diagram of clock pulses Fig. 52 Synchronous Clocked Sequential Circuit Prepared by M. Raja, CSE/KLU

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