What is a field programmable gate array (FPGA)? It is a type of semiconductor device with a matrix of configurable logic blocks and programmable interconnects. Unlike Application Specific Integrated Circuits (ASICs), FPGAs can be reprogrammed by users after purchase, enabling customization to specific application requirements. Do you want to learn more? Then we invite you to read this article!

What Is an FPGA?

A field programmable circuit is a type of integrated circuit that you can program and reprogram after manufacturing without the need to disassemble it. An FPGA contains configurable logic blocks along with programmable interconnects that make it possible for designers to configure them. As a result, these blocks can perform both simple and complex functions.

FPGAs are widely used in a number of devices from different fields and perform various functions. Examples of such systems using a field programmable gate array include:

  • Radar systems – Military radars for real-time signal processing.
  • Unmanned Aerial Vehicles (UAVs) – Flight control systems, sensor processing systems, or communication devices.
  • Cryptocurrency mining – To improve energy-efficiency
  • IoT and Edge Computing – Smart light bulbs, plugs, or sensors based on edge computing.
  • Embedded systems – FPGAs in embedded systems play a significant role, especially if the latter requires real-time data processing.
  • Computer vision systems – surveillance cameras or robots.
  • Prototyping – Using FPGAs to design ASICs.

The Meaning of FPGA Classification

FPGA, like many solutions related to embedded systems, can be classified based on some of its features. Let’s take a look at the different types:

  • SRAM-based FPGAs – As the name suggests, FPGAs of this type use static random-access memory for storing their configuration. They are flexible and may be configured at run time, but they do have one disadvantage: you need external memory to store the settings.
  • Antifuse-based FPGAs – This type of FPGAs uses antifuses that are programmable by applying high voltage. The main disadvantage, in this case, is that it’s impossible to reprogram once programmed antifuse.
  • Flash-based FPGAs – These field programmable gate arrays use non-volatile flash memory to store the configuration. Therefore, they are reprogrammable.
  • EEPROM-based FPGAs – EEPROM stands for electrically erasable programmable read-only memory, which, like flash memory, is non-volatile. Therefore, similarly to flash-based FPGAs, this type can be reprogrammed easily.
  • Hybrid FPGAs – Sometimes, a few of the solutions mentioned above are mixed. In such situations, you get a hybrid FPGA.

FPGA Architecture

Basic FPGA is built of thousands of configurable logic blocks (CLBs), which are surrounded by programmable interconnectors called fabric. The fabric routes the signal between the CLBs. Additionally, a field programmable gate array also contains I/O blocks which enable it to interact with external devices. (Bear in mind: CLBs may also be called logic blocks [LBs], logic elements [LEs], or logic cells [LCs] – it depends on the manufacturer and the company you’re working with.

A particular CLB contains the following elements: Look-Up Table (LUT), Multiplexer (MUX), and D Flip Flop. The LUT acts as a programmable memory for implementing combinational logical functions, while the MUX is the selector facilitating efficient data routing and enabling dynamic configuration. The D Flip Flop is simply a storage element holding the output of the LUT until the next clock cycle.

Why Use FPGAs? Practical Advantages

We wouldn’t discuss FPGAs if it weren’t for the benefits that they come with, both for embedded systems and other technologies. But, so far, we’ve focused only on FPGA theory and architecture – now it’s time to change that. Let's look at the practical advantages of this solution.

  • Performance – Speed, quick response times, and high processing power are what makes FPGAs stand out from the crowd. Though, we must say that ASICs are faster.
  • Flexibility – Reprogrammable FPGAs can be changed and modified to accommodate new functionalities, even post-manufacturing. This means that you can adjust them to the product or even correct mistakes without the need to build new prototypes.
  • Time-to-market – FPGA chips are widely available, and you can quickly program them, conduct the required tests, and launch your product. With ASICs, on the other hand, you need to wait months to go through all the production cycles.
  • Cost-effectiveness – This is partially true. For smaller data volumes, FPGAs are indeed less expensive than ASICs. This is due to the shorter production cycles. However, with larger volumes, this changes, and it’s frequently more profitable to opt for ASICs instead.
  • Low maintenance – You don’t need to invest resources into creating a new FPGA every time it needs an update. Instead, all you have to do is reprogram it. Therefore, in the end, they require much less maintenance than the alternatives.

The Takeaway

So, let’s sum this article up. What is a field programmable gate array? It’s a semiconductor device or chip that uses configurable blocks. Unlike OEM devices, it’s programmable and often reprogrammable, which gives it more flexibility. This is why an FPGA is often used to prototype and produce more complex application-specific integrated circuits (ASICs).

Additionally, you may find FPGAs in many IoT devices and embedded systems, including those operating in real-time, in fields such as defense, aviation, automotive, and cryptocurrency mining. Basically, they are a good choice wherever there’s a need for real-time data processing, and the data volumes are not excessively large.

Was this article helpful? If yes, then you should check out our other posts. Why don’t you take a look at Edge Computing vs. Cloud Computing: Key Differences to Know?