Flip Flops
14
Flip flops and latches • Basic memory elements of a sequential circuit, stores 1-bit information • Difference: Latches: Outputs are constantly affected by their inputs as long as the enable signal is asserted. Flip flops: Outputs change only either at the rising or falling edge of the enable signal. This enable signal is usually the controlling clock signal.
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Transcript of Flip Flops
Flip flops and latches• Basic memory elements of a sequential circuit,
stores 1-bit information• Difference: Latches: Outputs are constantly affected by their
inputs as long as the enable signal is asserted. Flip flops: Outputs change only either at the rising
or falling edge of the enable signal. This enable signal is usually the controlling clock signal.
types of latches and flip-flops:
• Set-Reset -latch and flip flop• D-latch and flip flop• JK-latch and flip flop• T-latch and flip flop
Simple Bi-stable element• If power is turned on Assume initially , Q = 1 then Q` = 0 the circuit is locked or latched to a ‘1’ Q = 0 then Q` = 1the circuit is locked or latched to a ‘0’
because it does not have any inputs, we cannot change the information bit that is stored in it.
Set-Reset latch using NAND Using NOR Truth table
Gated S-R latch
D-Latch
Gated D-latch
Clocked SR Flip flop
Clocked D Flip flop
Edge triggered flip flops
