Sheet 6
Synchronous Sequential Logic
1- Construct a JK flip-flop, using a D flip-flop, a two-to-one-line multiplexer, and an inverter.
2- Show that the characteristic equation for the complement output of a JK flip-flop is
Q'(t+1)=J'Q'+KQ
3- A sequential
Graphic symbol for edge-triggered D Flip-Flop
The arrowhead like symbol in front of Clk,
designates a dynamic input
A bubble outside the block adjacent to the dynamic
indicator designates negative edge triggered
The absence of the bubble designates pos
Contents (for the last ~5 lectures):
Instructor: Dr. Tamer ElBatt
Text Book: M. Mano and M. Ciletti, Digital Design, 4th
Ed., Prentice Hall, 2007
Chapter 5: Synch. Sequential Circuits, [Registers from Chapter 6]
Topics to be covered:
Introduction to
Flip-Flop Input Equations
Input Equations: the part of the combinational
circuit that generates the inputs to the flip-flops is
described by a set of Boolean functions called Input
Equations
For the previous example:
DA = Ax + Bx
DB = A`x
Output Equa
State Reduction and Assignment
Example 4: reduce the
shown state diagram, if
possible
We label the internal
states by letter symbols
instead of their binary
values
Only the input-output
sequences are important
The given state diagram
consists of 7 stat
Excitation Tables
Synthesis using flip-flops other than the D type is
complicated by the fact that the input equations
for the circuit must be derived indirectly from the
state table
For D flip-flops the input equations are obtained
directly from the ne