Contents
How can we implement preset and clear inputs in a flip-flop?
Asynchronous inputs on a flip-flop have control over the outputs (Q and not-Q) regardless of clock input status. These inputs are called the preset (PRE) and clear (CLR). The preset input drives the flip-flop to a set state while the clear input drives it to a reset state.
What are the drawbacks of J-K flip-flop?
JK flip-flop has a drawback of timing problem known as “RACE”. The condition of RACE arises if the output Q changes its state before the timing pulse of the clock input has time to go in OFF state. The timing pulse period (T) should be kept as short as possible to avoid the problem of timing.
What are the preset and clear inputs on the JK flip flop?
The PRESET and CLEAR inputs of the JK Flip-Flop are asynchronous, which means that they will have an immediate effect on the Q and Q’ outputs regardless of the state of the clock and / or the J and K inputs. It is important NOT to simultaneously activate the CLEAR and PRESET inputs.
When to reset flip flop with preset and clear?
The preset and clear input are active-low, because there are an inverting bubble at that input lead on the block symbol, just like the negative edge-trigger clock inputs. When the preset input is activated, the flip-flop will be reset (Q=0, not-Q=1) regardless of any of the synchronous inputs or the clock.
What are the J and K of a flip flop?
J and K are control inputs. These control inputs are named “J” and “K” in honor of their inventor Jack Kilby. JK Flip-Flop is called as a universal Flip-Flop or a programmable flip-flop because using its J and K inputs, the other Flip-Flops can be implemented. The PRESET and CLEAR inputs of a JK Flip-Flop
What happens when both preset and clear inputs are not activated?
When the clear input is activated, the flip-flop will be set (Q=1, not-Q=0), regardless of any of the synchronous inputs or the clock. So, what happens if both preset and clear inputs are not activated ( both of them 0 ) ?