FPGA stands for Field Programmable Gate Array. This is a well-known term among engineering and electronics enthusiasts. Essentially, FPGA is a huge array of programmable gates which can also be reconfigured anytime. Its description of “huge” may be misleading though. FPGA is by far complex compared to any simple set of gates. Some FPGA even have built-in hard blocks such as high-speed communication interfaces, memory controllers, PCI endpoints and many more.
Within the FPGA are lots of gates that can be connected together to come up with any circuit of choice. Its operation is almost similar to connecting individual logic gate ICs. Fundamentally, FPGAs are similar to CPLDs only that CPLDs are limited in capability and size as compared to FPGAs.
Modern FPGAs contain specialized components that are dedicated to specific functions. They also contain components for general purpose configurable logic. The combination of these dedicated components and configurable logic components has given rise to modules that perform more efficiently even with little power consumption.
What is it that makes FPGAs so special? Well, FPGAs can perform many operations in parallel. This means that so many activities can be done at the same time. Due to this feature, they have found extensive application in high-speed and high-performance processes which include telecommunications, image processing, digital signal processing among others.
Setting their complexity aside, FPGAs are fun to work with. You will hear this from anyone who has mastered their manipulation and programming. Actually, FPGAs use low-level programming and anyone can learn their operation starting from the basics. They are quite helpful for any student willing to learn and become an expert in digital electronics.
Basics of FGPA
In the manufacture of any circuit board, an FPGA is usually part of the components. The FPGA is programmed during this manufacturing stage but can late be reconfigured to make any desired changes. This feature makes FPGA different from ASIC (Application Specific Integrated Circuits). ASIC are usually custom manufactured for specific tasks.
With FPGAs, there is usually no processor tasked with running the software. The circuit is fully designed by the manufacturer. The configuration complexity of an FPGA may be as simple as that of an AND gate or as complex as that of a multi-core processor.
When creating a design, a Hardware Description Language (HDL) is first written. After that, it is synthesized into a bit file with the help of a BITGEN for the configuration of the FPGA. This configuration is stored by the FPGA in RAM. This means that the configuration is lost when there is no power and has to be reconfigured when the power comes back on.
They are prefabricated silicon chips that that can be electrically programmed to implement various digital designs. The FPGA architecture consists majorly of three components:
- Programmable Logic Blocks, for logic function implementation
- Programmable Routing
- I/O blocks, for making off-chip connections.
Programmable Logic Blocks
These blocks provide for basic storage and computation elements for any digital system. A basic logic block consists of a flip-flop, programmable combinational logic, and fast carry logic to minimize on area and delay.
Modern FPGAs will often have heterogeneous mixtures of different blocks such as multiplexers and dedicated memory blocks. Configuration memory is used throughout the logic blocks to manage the function of individual elements.
Programmable routing connects logic blocks and Input/output blocks to give a complete user-defined design unit. Programmable routing consists of pass transistors, multiplexers, and tri-state buffers. The pass transistors and multiplexers are responsible for connecting the logic elements.
Programmable I/O pads are used for interfacing the logic blocks and routing the architecture to external components. The I/O pad and logic circuit together form an I/O cell. In terms of space, these cells considerable amounts of space of the FPGA’s total area.
In I/O architecture design, it is important that selection of standards be done. This is important in increasing the silicon chip area for the I/O cells whenever large numbers of standards are used.
The FPGA architecture has developed over time, with the addition of functional blocks like block RAM, Arithmetic logic units, multiplexers, microprocessor, and DSP-48. This has come about due to the frequency of need for these special blocks for applications.
Also known as FPGA development process, FPGA programming entails the planning, designing and implementation of a solution on an FPGA. The degree and type of planning vary with applications. Creating a requirements document and design document to show the implementation of the proposed solution is helpful in any programming process.
Synthesis and programming are usually taken care of by the available vendor tools, including ISE, Vivado and Numato configuring tools.
Application of FPGAs
Architecturally, FPGAs from Direct Components are a pool of gates which can be reconfigured to come up with any circuit you may think of. This great flexibility plus the ability to reconfigure FPGAs make them a superior choice over ASICs (Application Specific Integrated Circuit) for many applications.
Different systems such as a deep learning system, application acceleration system or AI system can re-program an FPGA with different algorithms at different instances to achieve optimal results.In specific applications, the number of individual units produced would be little. Designing and producing ASICs for these applications can be very costly. In such circumstances, FPGA can offer desired and cost-effective solutions.
FPGAs have gained acceptance over the years and have found numerous applications. Below are some of the most common applications of FPGAs:
- Cryptography. In a world where data has become subject to many breaches, FPGAs have come in handy. The cryptography field reaps from the reconfigurable hardware (FPGAs) for various cryptographic applications.
- Industrial, Scientific and Medical Instruments
- FPGAs are also used in a wide range of applications such as random logic, device controllers, SPLDs, filtering, and communication encoding.
- FPGAs are also used in custom computing machines and systems.
- FPGAs offer a robust solution for meeting motor control, machine vision, industrial networking, and video surveillance.
- FPGAs are also useful in the emulation of large hardware systems through the use of interconnected FPGAs.