Cpld vs fpga pdf is not to be confused with Flip-chip pin grid array. Circuit diagrams were previously used to specify the configuration, as they were for ASICs, but this is increasingly rare. FPGAs contain an array of programmable logic blocks, and a hierarchy of reconfigurable interconnects that allow the blocks to be “wired together”, like many logic gates that can be inter-wired in different configurations.
Logic blocks can be configured to perform complex combinational functions, or merely simple logic gates like AND and XOR. In most FPGAs, logic blocks also include memory elements, which may be simple flip-flops or more complete blocks of memory. RAM blocks to implement complex digital computations.
Os and bidirectional data buses, it becomes a challenge to verify correct timing of valid data within setup time and hold time. Floor planning enables resource allocation within FPGAs to meet these time constraints.
FPGAs can be used to implement any logical function that an ASIC could perform. Some FPGAs have analog features in addition to digital functions.
The most common analog feature is programmable slew rate on each output pin, allowing the engineer to set low rates on lightly loaded pins that would otherwise ring or couple unacceptably, and to set higher rates on heavily loaded pins on high-speed channels that would otherwise run too slowly. Fairly common are differential comparators on input pins designed to be connected to differential signaling channels. However, programmable logic was hard-wired between logic gates. In the late 1980s, the Naval Surface Warfare Center funded an experiment proposed by Steve Casselman to develop a computer that would implement 600,000 reprogrammable gates.