Triggers Asynchronous RS-trigger T-triggers Synchronous RS trigger D-trigger JK-trigger

Triggers

Basic concepts
A trigger is an electronic device that can save one of two possible states.

Trigger inputs are divided into:

installation - to set the initial state of the trigger;

informational - to enter information;

Executive - to set the moment the trigger.

Triggers run on the front or on the slice


Designations of the impact of the executive impulse



Asynchronous RS trigger

S - set - set to “1” Designation
R - reset - reset to "0"
RS - asynchronous trigger, i.e. the transition from one state to another is not related to clock signals.

RS-Trigger Truth Table



Timing diagrams for an asynchronous RS trigger


Synchronous RS trigger

Designation


Preliminary on Q = "1", change on "0" is possible, when on R and C "1", if necessary on Q = 1, then S = 1 and C = 1, etc.

Timing charts

D-trigger

D-trigger - (delay delay data delay) - synchronous trigger, the output state of which coincides with the signal at its information input (D-input), which he had on the previous clock cycle synchronization
Symbol and the truth table of trigger triggering on the front



Timing charts


D-trigger delays for 1 clock cycle the information that exists at the input D.
On D - triggers, registers can be built to fill an 8-bit word with 8 D-triggers.
The information in the D-flip-flops is stored until the permission to change the information is received and then another number is written.

T- Triggers

The counting trigger (T-trigger) changes its state whenever there is an active signal level at its only information input T.

Designation

T-trigger - frequency divider by 2.

Timing charts


Truth table

JK trigger (universal)

Notation Truth Table


Timing charts




If we connect J and k, we get a T-trigger. T-trigger, when C = 1


D-trigger on JK-trigger