Fully configurable versatile field programmable function element

Abstract

A field configurable function element offers multi-function use of memory cells by organizing the cells in memory banks and by providing internal configurable interconnections of the memory banks. A versatile logic function configuration is obtained by storing the truth table of the desired logic functions in the memory cells. An arithmetic functions configuration is obtained by internally interconnecting the memory cells. A read/write memory function configuration is obtained by adding write address decoding, write enablement capability and input data leads. The configuration permits a parallel writing and reading of the memory cells, thereby effectuating a two-port memory operation. An added set of latches connected to the configurable function element and a configurable routing network connected to the inputs of the configurable function element, to the output of the configurable function element and to the output of the latches, form a powerful device that can be easily configured to any one of the three primary modes (logic, arithmetic and memory). A generalized routing fabric coupled to the routing network provides for configurable connections to other configurable function devices. To minimize the load that such a device may present to the routing fabric because of the various configurable interconnections that it can effect, the input leads from the routing fabric to the routing network in configurable function device are all multiplexed to one, or a few contact points, via an intermediate level of routing.