In the early days of ASIC technology, only logic library elements and basic I/Os with up to 10s of transistors were available for customizing gate arrays and/or logic functions in standard cell chips. And then, “megacells” (a.k.a. Functional Blocks, Semiconductor IP Blocks), comprised of 100s, even 1000s, and more transistors became available and offered proven memories, processor cores, data converters, special I/Os and many other widely used functions for integration in IC designs. These megacells enjoyed rapid market acceptance, mainly because they boosted designers’ productivity, reduced risk of failure, and cut development as well as unit cost.
Full Article: 3DInCities, Herb Reiter