Coarse and Fine grained architectures

Coarse-grained architectures consist of fairly large logic blocks, often containing two or more look-up tables and two or more flip-flops. In a majority of these architectures, a four-input look-up table (think of it as a 16x1 ROM) implements the actual logic. The larger logic blocks usually corresponds to improved performance.

Fine-grained circuits, consist of the basic cell being simple (OR, AND,and NOT).