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Class note #6
By Dr. Frank X. Li
ECEN 3733 Digital Circuit
Design
Flip Flops Summary
•To use memory in a larger circuit, we need to:
–Keep the latches disabled until new values are ready to be
stored.
–Enable the latches just long enough for the update to occur.
•A clock signal is used to synchronize circuits. The cycle time
reflects how long combinational operations take.
•Flip-flops further restrict the memory writing interval, to just the
rising edge of the clock signal.
–This ensures that memory is updated only once per clock cycle.
–There are several different kinds of flip-flops:
•SR flip-flops
•D flip-flop
•JK flip-flop
•T flip-flop
–They all serve the same basic purpose of storing bits.
