SEQUENTIAL AND COMBINATIONAL CIRCUITS,DIGITAL LOGIC DESIGN
DIGITAL LOGIC CIRCUITS~ INTRODUCTION TO COMBINATIONAL ANDSEQUENTIAL CIRCUITS.~DESIGN PROCEDURE OF COMBINATIONALCIRCUITS~ANALYSIS PROCEDURE OF COMBINATIONALCIRCUITSPRESENTED BY:QURATULAINBS(CS)-1QUAID-E-AZAM UNIVERSITYISLAMABAD ,PAKISTAN.
TYPES OF DIGITAL LOGICCIRCUITS COMBINATIONAL CIRCUITS SEQUENTIAL CIRCUITS
COMBINATIONAL CIRCUITS Combinational Circuits are made of logicgates. Doesn’t contain memory element , that’swhy they cant store any information. Value of present output is determined bypresent input. Examples of combinational circuits arehalf adders, full adders, sub tractors etc.
SEQUENTIAL LOGIC CIRCUITS Made up of combinational circuits andmemory elements. These memory elements are devicescapable of storing ONE-BIT information. Output depend on input and previousstate. Examples of sequential circuits are flipflops, counters, shift registers
TYPES OF SEQUENTIALCIRCUITSSequential circuits are of two types:1.SYNCHRONOUS CIRCUITS: In synchronous sequential circuits, the stateof the device changes only at discrete timesin response to a clock Pulse.2.ASYNCHRONOUS CIRCUITS: Asynchronous circuit is not synchronized bya clock signal; the outputs of the circuitchange directly in response to changes inInputs.
DESIGN PROCEDURE OFCOMBINATIONAL CIRCUITSThis procedure involves the followingsteps: The problem is stated. The number of available inputvariables and output variables isdetermined. The input and output variables areassigned letter symbols. Truth table is drawn Boolean function for output is obtained.
ANALYSIS PROCEDURE OFCOMBINATIONAL CIRCUIT TO DETERMINE THE OUTPUT FUNCTIONSAS ALGEBRAIC EXPRESSIONS. It is the reverse process of design procedure. Logic diagram of the circuit is given. Obtain the truth table from the diagram. Obtain Boolean function from the Truth Tablefor output.