ABSTRACT
Chips designed for a particular limited product or application are called application-specific integrated circuits (ASICs), and usually fall into one of five groups of semicustom components: programmable logic devices (PLDs), erasable programmable logic devices (EPLDs), field programmable gate arrays (FPGAs), gate arrays, and standard cells. An FSM can be designed as a Mealy machine or a Moore machine. The Mealy machine has outputs which may change with input changes in an asynchronous manner and cause erroneous behavior as signals ripple downstream. Row and/or column folding is a technique for reducing the physical size of a PLA by merging rows and/or columns and reducing the sparsity of the matrix. The maximum reduction in area is achieved if individual inputs and outputs are custom folded. The folded-NOR and folded-NAND array permit successive levels of NOR or NAND gates to be fed back and cascaded to implement multilevel logic designs. A folded-NOR array.
