CHAPTER 5 Sequential Circuits Latches Flip-Flops
CHAPTER 5: Sequential Circuits: Latches & Flip-Flops
Sequential circuit a There are two types of sequential circuits Synchronous(latch mode) sequential circuit: the behavior can be defined from knowledge of its signal at discrete instants of time. This type of circuits achieves synchronization by using a timing signal called the clock Asynchronous(fundamental mode) sequential circuit: the behavior is dependent on the order of input signal changes over continuous time, and output can change at any time(clockless)
Sequential Circuit ◼ There are two types of sequential circuits: ➢ Synchronous (latch mode) sequential circuit: the behavior can be defined from knowledge of its signal at discrete instants of time. This type of circuits achieves synchronization by using a timing signal called the clock. ➢ Asynchronous (fundamental mode) sequential circuit: the behavior is dependent on the order of input signal changes over continuous time, and output can change at any time (clockless)
Sequential circuit Models SYSTEM SYSTEM S OUTPUT VARIABLES VARIABLES COMBINATIONAL LOGIC STATE Mo EXCITATION VARIABLES VARIABlES AEMORY X
Sequential Circuit Models
Sequential circuit Models Falling or Negative Clock E CLOCK t+1 t+2 t+3 t+4
Sequential Circuit Models
Sequential circuit Models Excitation variables INPUT(t)斗 Combinational Combinational Memory ranson ogIc (f) g OUTPUT(O) State Variables
Sequential Circuit Models Excitation Variables Memory M State Variables CLK (E) Combinational Transform (f) INPUT(t) （S） Combinational Logic （g） OUTPUT(O)