SYEN 3330 Digital Systems

SYEN 3330 Digital Systems Chapter 6 – Part 1 SYEN 3330 Digital Systems

Outputs Inputs Combina-tional Logic Storage Elements Next State State Sequential Circuits SYEN 3330 Digital Systems

Overview of Chapter 6 • Types of Sequential Circuits • Storage Elements • Latches • Flip-Flops • Sequential Circuit Analysis • State Tables • State Diagrams • Sequential Circuit Design • Specification • Assignment of State Codes • Implementation • HDL Representation SYEN 3330 Digital Systems

Types of Sequential Circuits • Depends on time at which inputs are observed by storage elements and state of storage elements change • Synchronous • Behavior defined from knowledge of its signals at discrete instances of time • Storage elements affected by inputs and can change state only in relation to a timing signal (clock pulses from a clock) • Asynchronous • Behavior defined from knowledge of inputs at any instant of time and the order in continuous time in which inputs change • If clock just regarded as another input, all circuits are asynchronous! • Nevertheless, the synchronous abstraction makes complex designs tractable! SYEN 3330 Digital Systems

Discrete Event Simulation SYEN 3330 Digital Systems

Simulated NAND Gate SYEN 3330 Digital Systems

Storing State SYEN 3330 Digital Systems

Storing State (Continued) • The circuit becomes: SYEN 3330 Digital Systems

Storing State (Continued) SYEN 3330 Digital Systems

Basic NAND S -R Latch SYEN 3330 Digital Systems

Simulating S -R Latch SYEN 3330 Digital Systems

Basic S - R Latch SYEN 3330 Digital Systems

Clocked S - R Latch SYEN 3330 Digital Systems

Clocked S - R Latch (Continued) SYEN 3330 Digital Systems

Characteristic Equation for S - R Latch SYEN 3330 Digital Systems

D Latch SYEN 3330 Digital Systems

J-K Latch SYEN 3330 Digital Systems

T Latch SYEN 3330 Digital Systems

SYEN 3330 Digital Systems