What Is an FPGA?

How Does It Work?

Inside it there are thousands of programmable logic blocks (LUTs), registers and interconnect. The circuit described in VHDL/Verilog defines how these blocks connect; so the chip turns into the desired hardware.

Difference From a Processor

A processor runs instructions in sequence; an FPGA builds real parallel hardware. So it can do many operations at once, very fast.

Relationship to the ASIC

An FPGA is flexible but expensive per unit; an ASIC is fixed but very cheap at high volume. Designs are usually prototyped on an FPGA and, once mature, moved to an ASIC. For smaller programmable logic the CPLD, and for designs that put a processor and peripherals on one chip the SoC (system on chip), are related concepts.

Where Is It Used?

Signal processing, image/video processing, high-speed data, prototyping, AI acceleration and low-volume custom hardware.

The Basic Building Blocks Inside

An FPGA is made of three main resources: lookup tables (LUTs) build logic functions, flip-flops store data and programmable interconnect ties them together. Modern FPGAs also include ready multipliers (DSP), block RAM and even embedded processor cores; this makes them a powerful system on their own.

Common Mistakes

• Thinking like software: an FPGA is parallel hardware; it isn't written with sequential-program logic.
• Timing: if clock constraints aren't met the design runs unstably.
• Power: large FPGAs can need serious power and cooling.