Programmable logic cells with local connections

Abstract

A programmable logic structure is disclosed employing input logic routing cell (ILRC) multiplexers and output logic routing cell (OLRC) multiplexers for making local connections between dedicated logic cells. In a simple programmable logic structure, a dedicated logic cell (DLC) is implemented in a programmable logic structure comprising multiple ILRC multiplexers for port A and multiple OLRC multiplexers for port B. In a multi-level programmable logic structure, multiple columns of dedicated logic cells is designed with columns of dedicated local cells adjacent to each other where each DLC column is used to implement a particular logic function. In a first embodiment, local connections can be made between dedicated logic cells, e.g. an OLRC in a first DLC at level L making local point-to-point connections to an ILRC in a second DLC at level L+1. In a second embodiment, local connections can be made from any other dedicated logic cells, whether positioned horizontally or vertically relative to a relative point or multiplexer, and from any offset from a current logic and routing cell (LRC). In a third embodiment, local connections can be made by stitching a first OLRC to a second OLRC (for connecting to an ILRC), which allows lines from other columns or levels of DLC to reach an ILRC for a fast local interconnect.