All mechanical switches will ‘bounce’ when closed which means the contacts do not make immediate firm contact. The consequence of this is that the actual voltage from the switch oscillates when contac...

The ‘memory’ of previous outputs in an asynchronous sequential circuit is provided by direct feedback from the internal output(s), Y, to the internal input(s), of the combinational logic block (see Fi...

In this introductory text we will define two broad classes of sequential circuits, namely; asynchronous and synchronous.• The timing of the operation of asynchronous circuits, as the name implies, is ...

All of the circuits so far considered in this book have been combinational. This means that their outputs are dependent only upon the inputs at that time. We now turn our attention to sequential logic...

Heuristic implementations can broadly be considered as those that are not produced by rigorous application of Boolean logic theory. (Remember that any truth table can» in theory, be implemented in fun...

A four-bit binary adder is required to add together two four-bit binary numbers plus one carry-in bit, and produce a four-bit sum plus a carry-out bit. This is shown diagramatically in Fig. 4.14. ...

In this section we consider the design of a four-bit adder; i,e. a circuit that adds together two four-bit binary numbers. This needs to be a combinational logic circuit and therefore serves as a usef...

Because all 2m possible combinations of the m control lines of a multiplexer are fed to 2m AND gates then there is an AND gate for all of the fundamental product terms of the m variables....