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What is a interface?

SystemVerilog introduces the concept of an "interface" to facilitate communication between different hardware blocks or modules. An interface serves as a bundle of related signals, representing a communication protocol or a collection of signals with a shared purpose. Much like a struct in software programming, an interface allows the grouping of signals into a cohesive unit, promoting modularity and code reusability.

The key advantages of using interfaces include portability, reusability, and encapsulation. Once defined, an interface can be easily reused across multiple modules or testbenches, reducing redundancy and making the code more maintainable. It must also be noted that interfaces are static by nature just like a module and hence memory for it is allocated during the elaboration period of the simulation run. Interfaces also create a clear boundary between modules, improving code organization and minimizing naming conflicts.

Code 
// Filename : basic_if.sv

interface basic_if (
	input clk,
	input rst_n
);

    clocking basic_cb @(posedge clk);	
    endclocking: basic_cb
    
    logic [7:0] random_input;
    logic [7:0] random_output;
    wire [7:0] random_inout;

endinterface: basic_if
Theory Questions
    Using dot notation (e.g., intf.signal).
    Yes, an interface can be parameterized to make it more flexible and reusable, allowing customization of its width or other characteristics based on the parameters passed during instantiation.
    Yes, an interface can be instantiated multiple times in a module, each time with a different instance name, allowing for multiple connections or communication channels in the design.
    By bundling signals together, interfaces eliminate the need to connect individual signals manually, reducing the risk of mismatches in signal names, sizes, or directions during module instantiation.
    Yes, logic variables can be defined inside an interface, and they can be used to hold the state or data related to the signals within the interface, simplifying the signal management within the design.
    Yes, an interface can group signals and share them across multiple modules.
    Interfaces improve readability by encapsulating related signals and reducing the complexity of module connections.
    Yes, interfaces can include continuous assignments to define the relationships between signals. 
    interface modport_if;
    logic clk, rst_n, data;
    modport master (input clk, rst_n, output data);
    modport slave  (input clk, rst_n, input data);
endinterface

    interface param_if #(parameter WIDTH = 8);
    logic [WIDTH-1:0] data;
endinterface

    interface clk_if (input logic clk);
    clocking cb @(posedge clk);
        input data;
        output valid;
    endclocking
endinterface

    interface assign_if;
    logic a, b, c;
    assign c = a & b;  // Continuous assignment
endinterface

    interface task_if;
    logic data;
    task set_data(input logic d);
        data = d;
    endtask
endinterface