The basic characteristics of the trigger

Crystal oscillator

Quartz Oscillator 3225 20M OSC

A flip-flop is a basic unit circuit that constitutes a sequential logic circuit. It is a logic component with memory function. The basic characteristics of triggers are:
(1) having two complementary outputs Q and /Q;

(2) having two stable states of "0" state and "1" state;

(3) State transition, ie flipping, can be achieved under the action of an external signal;

(4) The external signal disappears with a memory function, which allows the trigger to memorize binary information.

According to the stable working state, it can be divided into a bi-stable flip-flop, a monostable flip-flop, an unsteady flip-flop (multi-vibrator), etc.; according to the logical function division, it can be divided into RS flip-flop, D flip-flop, T flip-flops, JK flip-flops, etc.; according to the circuit structure, can be divided into basic RS flip-flops, synchronous flip-flops (clock-controlled flip-flops), master-slave flip-flops, sustain-blocking flip-flops and edge-triggered Several types of devices. The circuit structure of the flip-flop is different, and the trigger flip mode and working characteristics are also different. Triggers with some logic function can be implemented with different circuit structures. Divided by trigger mode, it can be divided into level trigger and edge trigger. Level triggering has two types: high level trigger and low level trigger, while edge trigger has two kinds of rising edge trigger and falling edge trigger.
The representation of the logic function of the trigger is:

(1) Status table or function table: The status table includes the value of the input excitation signal, the value of the original state (also known as the initial state) of the trigger and the state of the inverted state (also known as the secondary state). The function table only lists the input excitation signal value and the trigger secondary state value, which is relatively simple.

(2) State equation: A logical equation written by the state table.

(3) State transition diagram.

(4) Waveform diagram (also called timing diagram): Draw an output state waveform corresponding to the input state waveform.