Introduction to FPGAs
What is an FPGA?
A Field-Programmable Gate Array (FPGA) is a unique type of integrated circuit that allows you to implement a custom digital design. Unlike fixed-function chips, FPGAs are flexible and can be reconfigured.
How are FPGAs Customized?
- Design: The system is first designed using a hardware description language (HDL) such as VHDL or Verilog.
- Synthesis: The HDL code is then synthesized using software tools (similar to compilers) to produce an output file.
- Download: This output file, containing binary data, is downloaded into the FPGA’s special memory, configuring its internal logic.
FPGAs vs. Microcontrollers
- Flexibility: FPGAs are highly flexible and reconfigurable, whereas microcontrollers are Application-Specific Integrated Circuits (ASICs) with fixed functions.
- Execution: FPGAs do not execute code in the same way microcontrollers do. They implement digital circuits.
- Capabilities: FPGAs can behave as any digital system and may even contain a CPU.
- Evolution: Embedded systems, traditionally based on microcontrollers/microprocessors, have evolved to incorporate FPGAs for increased flexibility and performance.
Applications of FPGAs
FPGAs have a vast and broad range of applications, similar to microcontrollers, including:
- Automotive
- Consumer electronics
- Medical devices
- Defense
Key Manufacturers
Approximately 90% of the FPGA market is supplied by two major manufacturers:
- Xilinx (acquired by AMD)
- Altera (acquired by Intel)
Basic Elements in FPGAs
FPGAs are composed of several basic elements:
- Logic Blocks: These contain digital devices such as lookup tables, flip-flops, and multiplexers. They implement the design and are also known as Configurable Logic Blocks (CLBs), which are further subdivided into logic cells. Logic cells typically do not contain individual logic gates.
- Interconnect Block: An extensive network of switches that connects the various components as required by the design.
- I/O Blocks: Contain the circuitry for the input and output pins of the integrated circuit.
- Memory Blocks: Used to implement large arrays of memory.
- Clock Management Block: Essential for implementing sequential systems.