Simple programmable logic device: Difference between revisions

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== Basic Description ==

Simple programmable logic devices (SPLD) are the simplest, smallest and least-expensive forms of programmable logic devices. SPLDs can be used in boards to replace 7400-seriesstandard TTLlogic components (AND, OR, and NOT gates), such as 7400-series TTL.

They typically comprise 4 to 22 fully connected macrocells. These macrocells typically consist of some combinatorial logic (such as AND OR gates) and a flip-flop. In other words, a small Boolean logic equation can be built within each macrocell. This equation will combine the state of some number of binary inputs into a binary output and, if necessary, store that output in the flip-flop until the next clock edge. Of course, the particulars of the available logic gates and flip-flops are specific to each manufacturer and product family. But the general idea is always the same.