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The term flip-flop has historically referred generically to both level-triggered (asynchronous, transparent, or opaque) and edge-triggered (synchronous, or clocked) circuits that store a single bit of data using gates. [1] Modern authors reserve the term flip-flop exclusively for edge-triggered storage elements and latches for level-triggered ones.
The output of a flip-flop is constant until a pulse is applied to its "clock" input, upon which the input of the flip-flop is latched into its output. In a synchronous logic circuit, an electronic oscillator called the clock generates a string (sequence) of pulses, the "clock signal".
In a synchronous circuit, two registers, or flip-flops, are said to be "sequentially adjacent" if a logic path connects them. Given two sequentially adjacent registers R i and R j with clock arrival times at the source and destination register clock pins equal to T Ci and T Cj respectively, clock skew can be defined as: T skew i, j = T Ci − T Cj.
If the output of the flip-flop is low, and a high clock pulse is applied with the input being a low pulse, then there is no need for a state transition. The extra computation to sample the inputs cause an increase in setup time of the flip-flop; this is a disadvantage of this technique. [3]
The Timing closure in VLSI design and electronics engineering is the process by which a logic design of a clocked synchronous circuit consisting of primitive elements such as combinatorial logic gates (AND, OR, NOT, NAND, NOR, etc.) and sequential logic gates (flip flops, latches, memories) is modified to meet its timing requirements.
Synchronizers may take the form of a cascade of D flip-flops (e.g. the shift register in Figure 3). [7] Although each flip-flop stage adds an additional clock cycle of latency to the input data stream, each stage provides an opportunity to resolve metastability. Such synchronizers can be engineered to reduce metastability to a tolerable rate.
D : Q; where Dff is the D-input of a D-type flip-flop, D is the module information input (without CE input), and Q is the D-type flip-flop output. This type of clock gating is race-condition-free and is preferred for FPGA designs. For FPGAs, every D-type flip-flop has an additional CE input signal.
Flip-flop and latch are not the same; so, they deserve separate pages (as it is). Flip-flop and latch are closely related; so, the two pages have to be closely related as well. The latch precedes chronologically the flip-flop. Eccles and Jordan have invented a latch, not a flip-flop; so, the data about their patent have to be placed on Latch.