Search results
Results From The WOW.Com Content Network
The D flip-flop is widely used, and known as a "data" flip-flop. The D flip-flop captures the value of the D-input at a definite portion of the clock cycle (such as the rising edge of the clock). That captured value becomes the Q output. At other times, the output Q does not change. [23] [24] The D flip-flop can be viewed as a memory cell, a ...
Registers (usually implemented as D flip-flops) synchronize the circuit's operation to the edges of the clock signal, and are the only elements in the circuit that have memory properties. Combinational logic performs all the logical functions in the circuit and it typically consists of logic gates .
An arrangement of D flip-flops is a classic method for integer-n division. Such division is frequency and phase coherent to the source over environmental variations, including temperature. The easiest configuration is a series where each D flip-flop is a divide-by-2. For a series of three of these, such a system would be a divide-by-8.
quad D flip-flops, clear 16 SN74LS171: 74x172 1 16-bit multiple port register file (8x2) three-state: 24 SN74172: 74x173 4 quad D flip-flop, asynchronous clear three-state: 16 SN74LS173A: 74x174 6 hex D flip-flop, common asynchronous clear 16 SN74LS174: 74x175 4 quad D edge-triggered flip-flop, complementary outputs and asynchronous clear 16 ...
In a synchronous counter, the clock inputs of the flip-flops are connected, and the common clock simultaneously triggers all flip-flops. Consequently, all of the flip-flops change state at the same time (in parallel). For example, the circuit shown to the right is an ascending (up-counting) four-bit synchronous counter implemented with JK flip ...
Flip-flop excitation tables [ edit ] In order to complete the excitation table of a flip-flop , one needs to draw the Q(t) and Q(t + 1) for all possible cases (e.g., 00, 01, 10, and 11), and then make the value of flip-flop such that on giving this value, one shall receive the input as Q(t + 1) as desired.
D: Q; where: Dff is D-input of D-type flip-flop, D is module information input (without CE input), Q is 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.
Nevertheless, most systems need to accept external unsynchronized signals into their synchronous logic circuits. This interface is inherently asynchronous and must be analyzed as such. Examples of widely used asynchronous circuits include synchronizer flip-flops, switch debouncers and arbiters.