GENERAL DESCRIPTION
The central switch matrix connects the PAL blocks to each other and to all input pins, providing a high degree of connectivity between the fully-connected PAL blocks. This allows designs to be placed and routed efficiently. Routability is further enhanced by an input switch matrix and an output switch matrix. The input switch matrix provides input signals with alternative paths into the central switch matrix; the output switch matrix provides flexibility in assigning macrocells to I/O pins. The MACH435 has macrocells that can be configured as synchronous or asynchronous. This allows designers to implement both synchronous and asynchronous logic together on the same device. The two types of design can be mixed in any proportion, since the selection on each macrocell affects only that macrocell. Up to 20 product terms per function can be assigned. It is possible to allocate some product terms away from a macrocell without losing the use of that macrocell for logic generation.
Lattice
