Sequential Circuit Models Yo Combinational logic Universal combinational circuit model No memory units No feedback from logic outputs back to the inputs
simple counters Counting is a fundamental function of digital circuits. A digital counter consists of a collection of flip-flops that change states (set or reset) in a prescribed sequence
FLIP-FLOPS Flip-flops are digital devices that have the ability to store binary information after the excitation input has changed. They are considered to be the basic memory cell for the majority of electronic binary data storage applications. This section explores the flip-flop from a functional perspective
Hazard o Boolean algebra does not account for propagation delays through signal paths of actually circuits. o The delay can cause glitches to occur. A glitch is an unwanted signal, usually short pulse caused by the transient behavior of signal path that have different delays A hazard exists any time the potential for glitches is present
Basie cCoucept Boolean algebra (Logic algebra) is closure mathematical system that defines a series of logic operation (and, or, not) performed on set k of variables (a, b,...) which can only have two values of 0 or 1
A function is a term used in mathematics and logic to denote a relationship between input and output variables. Each variable is restricted to binary (0, 1) values The relationship is the complex of three primitive functions (And \\Not\\Or)
Positional Number System Number system use positional notation to represent value. The position of the character(numeral) in a character string (collection of possible numerals) indicate value as well as the character itself. Radix (base) is the number of numeral characters in the character set of positional number system. Position Weiaht is a constant that represents the value of a position. Different position has different weight. It is the integer power of radix
