FPGA In Layman''S Terms

FPGA is an Integrated Circuit which can be reconfigured again and again to perform different tasks as desired. For example, an FPGA can be configured to function as a processor, and then it can be reconfigured to function as a Graphics Processing Unit (GPU), or hardware video encoder, or something else. The point is that FPGA can theoretically be programmed to function as any other Digital Integrated Circuit.

Think of FPGA as a breadboard for Digital Circuits. All the gates and flip-flops are present on the FPGA, and there are wires going through the complete chip. Circuits are made by connecting these wires to the relevant gates or flip-flops as per intended design. Instead of connecting the gates/flip-flops using a physical wire as in a breadboard, FPGAs has programmable interconnects that can be rewired programmatically. There are dedicated wires/routes for clock signals and only a selected number of FPGA pins are allowed to drive those global clock routing wires.

FPGA Vs Microcontroller

Microcontroller only allow firmware to be re-programmed. The hardware and interconnects are fixed but the FPGA are highly flexible with the ability to change the hardware. Microcontrollers can be programmed again and again with different software (i.e. firmware) and their functionality changes with the firmware running on them. FPGAs can be programmed again and again with different hardware design (hardware description) and their functionality changes with the hardware design running on them. 

How does a FPGA Work?

An FPGA is programmed using a Hardware Description Language (HDL), such as Verilog or VHDL. The HDL specifies how the FPGA should behave and what functions it should perform. An increasingly popular way to program for FPGA is High-Level Synthesis (HLS) in which the design is done in a subset of C and the compiler transforms the design into correct Verilog code

Once the HDL code is developed, it is compiled into a configuration file. The configuration file is then uploaded onto the FPGA using a device programmer.

The FPGA then executes the programmed logic based on the configuration file, performing the tasks that it was designed to do.

Features of a FPGA!

Parallelism: An FPGA has thousands of logic blocks, all of which you can program. You can create processes independent of one another, decreasing instances of bottlenecking as with microcontrollers.

Customization: Simply put, if you know what you’re doing, you can do a lot more with an FPGA than a microcontroller. If you want to program something complicated, you’ll need more customizability than a microcontroller provides.

Complex applications: Because FPGAs allow for parallel processes, you can implement more inputs with an FPGA than with a microcontroller, without running into a bottlenecking issue. This makes them ideal for more complex operations.

Flexibility: One of the biggest benefits of an FPGA is that the hardware itself can be changed after its initial programming. For this reason, you can change a device’s function without completely replacing its hardware. This is more cost-effective in the long run, especially for mass-producing industries.