Inventors:
Om P. Agrawal - Los Altos CA, US
Fabiano Fontana - San Jose CA, US
Gilles M. Bosco - San Jose CA, US
Assignee:
Lattice Semiconductor Corporation - Hillsboro OR
International Classification:
H03K 19177
Abstract:
Structures and techniques are provided for allowing one or more of the following actions to occur within a Complex Programmable Logic Device (CPLD): (1) Elective use of a fast, allocator-bypassing path (e. g. , a fast 5-PT path) in combination with in-block simple or super-allocation; (2) Elective use of an OSM-bypassing path for signals that do not need pin-consistency; (3) Automatic re-routing of output enable signals that corresponding to output signals which are re-routed for pin-consistency purposes; (4) Global distribution of globally-usable output enable signals; (5) Elective use of two-stage steering to develop complex sum-of-clusters terms where fast path or simple allocation will not be sufficient; and (6) Use of unidirectional super-allocation with stage-2 wrap-around in designs having about 24 or less macrocell units per logic block. Techniques are provided for concentrating the development of complex function signals (e. g. , ≦80PTs) within singular logic blocks so that the development of such complex function signals does not consume inter-block interconnect resources.