The Cyclone II architecture is a two-dimensional row and column-based architecture used to implement custom logic. The logic array consists of logic elements (LEs), with 16 LEs in each array. Cyclone II devices feature a global clock network and up to four phase-locked loops (PLLs). M4K memory blocks are true dual-port memory blocks with 4K bits of memory plus parity. These features make Cyclone II devices powerful programmable logic devices.