Have you ever seen the inside of an electric circuit board? There are so many blocks and interconnected circuits that you will have a hard time understanding which circuit is connecting which point. One of the main components of this electric circuit is the FPGA board or the Field Programmable Gate Array board. It is a special device that is widely used in the electric circuits and they help to create the logical blocks and the interconnection among other circuits. FPGAs are basically semiconductor devices that can be programmed according to the function that is required in the circuit.
Previously, ASIC or Application Specific Integrated Circuits were used instead of FPGA. They were manufactured for a particular task and they could not be reprogrammed. However, with the introduction of FPGA boards, ASIC slowly started to lose its ground. This is because FPGA provided the facility to program and reprogram according to the purpose that the circuit was designed for.
The complex structure of an FPGA board can be a bit difficult to understand. The array of gates are rather complex in nature and most of the FPGA boards have in-built hard blocks like PCIe Endpoints, high-speed communication interfaces, and memory controllers. One of the reasons why this kind of board managed to make a mark in the electric circuit is that many of the gates that are used in the FPGA board are arbitrarily connected so that they can make a circuit that is tailor-made for you. If you have managed to connect individual logical gates previously, you will understand how easy the working of an FPGA is. Many programmers have said that FPGAs have a similar structure as CPLDs or Complex Programmable Logic Devices but their only difference is in the size. FPGAs are much bigger and are more capable than CPLDs.
Architecture of FPGA board
The architecture of an FPGA board has three main parts. They are:
- Programmable routing that implements each and every function.
- I/O blocks that are largely used to make off-chip connections.
- Programmable logic blocks that are mostly used to implement the logical functions.
The prefabricated silicon chips that are used in the FPGA boards can be electrically programmed so that the digital designs can be implemented without any issue. The modern EPGA that are used in the circuits contain near about 330,000 logic blocks and more than 1100 inputs and outputs combined. Let’s take a deeper look at the different components of the FPGA board:
This part is responsible for establishing a connection between different input and output blocks along with the logic blocks so that a comprehensive customized design unit can be created. Some of the most important parts of the programmable routing section are tri-state buffers and multiplexers pass transistors. These are used in the logic clusters in order to connect all the logical elements together.
There are several programmable I/O pads that act as the interface between the routing architecture and logic blocks. These are then connected to the external components to provide the desired structure to the FPGA board and in turn the electric circuit. The programmable I/O is the biggest structure in the FPGA board and the design is quite complicated. There are many differences in the reference and supply voltage. An important part of the programmable I/O is the selection of standards. The FPGA board will be dependent on the number of standards because that will decide the actual silicon chip area that is required for the I/O cells. The more the number of standards will need a larger area and vice versa.
Programmable logic blocks
This is the most important part of an FPGA board because it provides the storage elements and basic computation that is used in the digital systems. It is that part that makes FPGA more modern and ASIC to be more backdated. The logic elements will have all the programmable combinational logic. If you look at the latest FPGAs, they will have a mixture of various blocks such as multiplexers and dedicated memory blocks. The configuration memory that will be used in the logic blocks will have the ability to control some of the specific functions of different elements.
Applications of FPGA board
Since FPGA boards can be programmed and reprogrammed, they can be used in almost any digital circuit that you can think of. Some of the most common applications of FPGA are as follows:
- ASIC prototyping
- Military and space applications
- AI, Deep learning, and high-performance computing
- Medical, scientific, and industrial instruments
- Packet processing, networking, and various other communications
- Image and audio-video processing and broadcasting
Design flow of FPGA architecture
Just like the architecture of the FPGA board, the design flow also has some important components that help in the smooth functioning of the board.
- The design verification comprises of timing verification and functional verification that takes place during the time of the design flow.
- The design entry part is done using different techniques such as hardware description language, schematic based, or a combination of both the techniques. If you want an algorithmic variant, the HDL technique can be used. On the other hand, if you want a hardware variant, then the schematic base technique will be applied.
- The design implementation process includes the place and route, the map, and the translated codes.
- Lastly, the design synthesis translates all the VDHL code into a specific device netlist format. This helps to optimize the design according to the design architecture that is required. The final netlist will be saved as an NGC or Native Generic Circuit file.
The electronic industry has used prototyping and simulations for decades now. Most of the companies have their own protocols and standards for making hardware. This makes it difficult to come up with task-based boards. But if you are using an FPGA board, you will not have to think of any protocol because you can customize the board according to any standard or protocol you want.