Sequential logics
- 1. SEQUENTIAL LOGICS A form of binary circuit design. Employs one or more inputs and one or more outputs. States are related by defined rules that depend, in part, on previous states. Each of the input(s) and output(s) can attain either of two states: logic 0 (low) or logic 1 (high). EXAMPLE: A common example is flip-flop.
- 2. FLIP-FLOP A device that can store 1 bit of information. It is a clocked device, which can change its value only at positive clock edges. When the clock is not at a positive edge, the flip- flop maintains (holds) its value.
- 3. Q Q’ Inputs Normal Output Inverted Output They have two stable sates and can be switched from one to the other by appropriate inputs. These stable conditions are usually called the states of the circuit.
- 4. TYPES OF FLIP-FLOPS There are four types of flip-flops. Basic RS flip-flop Clocked RS flip-flop JK flip-flop D flip-flop T flip-flop Master slave flip-flop
- 5. D FLIP-FLOP Also known as data flip-flop. Can be constructed from RS flip-flop by adding an inverter. Inverter is added so that the R input is always the inverse of S(or J input is always complementary of K).
- 7. D Q Q (New) Operations 0 0 0 Reset 0 1 0 Reset 1 0 1 Set 1 1 1 Set TRUTH TABLE
- 8. T FLIP-FLOP Also known as toggle flip-flop. It has only the toggle and hold operation. If toggle mode operation. The output will toggle from 1 to 0 or vice versa.
- 10. T Q Q(new) Operations 0 0 0 Hold 0 1 1 Hold 1 0 1 Toggle 1 1 0 Toggle TRUTH TABLE