What is a Look-Up Table (LUT) in an FPGA, and how does it work?
A Look-Up Table (LUT) in an FPGA is a fundamental building block used to implement combinational logic (logic that depends only on the current input values). It acts as a programmable truth table, allowing the FPGA to emulate virtually any Boolean logic function (e.g., AND, OR, XOR) based on how it is configured. Here’s a detailed explanation: What is a LUT? A LUT is a small, fast memory block that stores precomputed output values for all possible combinations of its inputs. In FPGAs, LUTs are the core of Configurable Logic Blocks (CLBs) , which form the programmable fabric of the device. A LUT with n inputs can implement any Boolean function of those n variables. For example: A 2-input LUT can emulate AND, OR, NAND, XOR, etc. A 4-input LUT (common in modern FPGAs ) can implement more complex functions. How Does a LUT Work? 1. Truth Table Storage : A LUT behaves like a truth tab...