ECE201Notes(7)

ECE201Notes(7) - ECE 201 Digital Logic Chapter 7 1 of 27...

Info iconThis preview shows pages 1–7. Sign up to view the full content.

View Full Document Right Arrow Icon
ECE 201 Digital Logic Chapter 7 1 of 27 Synchronous Sequential Networks 7.1 Structure and Operation of Clocked Synchronous Sequential Networks Sequential Logic – Digital Logic which contains both combinational elements and memory elements. Synchronous Sequential Logic – Sequential Logic whose behavior can be defined from the knowledge of its signals at discrete instants of time. Asynchronous Sequential Logic – Sequential Logic whose behavior depends on the order in which its inputs are changed and can be affected at any instant of time.
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
ECE 201 Digital Logic Chapter 7 2 of 27 Characteristic Tables Characteristic Tables are used to state what the new output, Q(t+1) , of the Flip-flop will be given the present inputs and the past output, Q(t) . They are used to analyze a sequential circuit and determine the state table corresponding to it. J-K Flip-Flop R-S Flip-Flop J K Q(t+1) S R Q(t+1) 0 0 Q(t) No Change 0 0 Q(t) No Change 0 1 0 Reset 0 1 0 Reset 1 0 1 Set 1 0 1 Set 1 1 Q’(t) Toggle 1 1 ? Unknown D Flip-Flop T Flip-Flop D Q(t+1) T Q(t+1) 0 0 Reset 0 Q(t) No Change 1 1 Set 1 Q(t)’ Toggle
Background image of page 2
ECE 201 Digital Logic Chapter 7 3 of 27 7.2 Analysis of Synchronous Sequential Networks Sequential Circuit Example with Data Flip-Flops B y B’ Clk A A’ x Q’ Q’ Q Q D D A(t+1) = D A = A(t)x(t) + B(t)x(t) = Ax + Bx B(t+1) = D B = A’(t)x(t) = A’x y(t) = [A(t) + B(t)] x’(t) = (A + B) x’ Present State ---------- Input ------- Next State -------- Output -------- Flip-Flop Inputs -------------- A B x A B y D A D B 0 0 0 0 0 0 0 0 0 0 1 0 1 0 0 1 0 1 0 0 0 1 0 0 0 1 1 1 1 0 1 1 1 0 0 0 0 1 0 0 1 0 1 1 0 0 1 0 1 1 0 0 0 1 0 0 1 1 1 1 0 0 1 0
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
ECE 201 Digital Logic Chapter 7 4 of 27 D A = Ax + Bx D B = A’x y = (A + B) x’ Present State ---------- Input ------- Next State -------- Output -------- A B x A B y 0 0 0 0 0 0 0 0 1 0 1 0 0 1 0 0 0 1 0 1 1 1 1 0 1 0 0 0 0 1 1 0 1 1 0 0 1 1 0 0 0 1 1 1 1 1 0 0 Alternate Form of the State Table Present State ---------- Next x = 0 ------- State x = 1 -------- Output x = 0 -------- Output x = 1 -------- A B AB A B y y 0 0 0 0 0 1 0 0 0 1 0 0 1 1 1 0 1 0 0 0 1 0 1 0 1 1 0 0 1 0 1 0 00 0/0 0/1 0/1 0/1 1/0 1/0 1/0 1/0 11 10 01
Background image of page 4
ECE 201 Digital Logic Chapter 7 5 of 27 State Diagram U S N K I T C 0/0 0/1 1/1 1/1 1/0 1/0 1/0 1/0 1/1 0/1 0/1 0/0 0/0 0/0 State Input Output U 1 0 1 1 0 0 0 1
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
ECE 201 Digital Logic Chapter 7 6 of 27 Sequential Circuit Example with J-K Flip-Flops B Clk A x Q’ Q J K Q’ Q J K J A = B K A = Bx’ J B = x’ K B = A’x + Ax’ Present State ---------- Input ------- Next State -------- Flip-Flop Inputs -------------- A B x A B J A K A J B K B 0 0 0 0 1 0 0 1 0 0 0 1 0 0 0 0 0 1 0 1 0 1 1 1 1 1 0 0 1 1 1 0 1 0 0 1 1 0 0 1 1 0 0 1 1 1 0 1 1 0 0 0 0 0 1 1 0 0 0 1 1 1 1 1 1 1 1 1 1 0 0 0 00 1 1 1 0 0 0 1 0 01 10 11
Background image of page 6
Image of page 7
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 04/20/2008 for the course ECE 201 taught by Professor Ried during the Spring '08 term at Clemson.

Page1 / 27

ECE201Notes(7) - ECE 201 Digital Logic Chapter 7 1 of 27...

This preview shows document pages 1 - 7. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online