verilog rom

Verilog ROM (Read-Only Memory) is a hardware construct used in digital circuit design. It is a memory module that stores data permanently and can only be read, hence the name "read-only." In Verilog, ROMs are typically implemented using lookup tables (LUTs) or case statements.

To create a Verilog ROM, you can define a memory array a specific size and initialize it with the desired data values. Here's an example of a simple 8-bit ROM with 4 memory locations:

module ROM_example (
    input [1:0] address,
    output reg [7:0] data
);

reg [7:0] memory [0:3];

initial begin
    memory[0] = 8'b00000000;
    memory[1] = 8'b00000001;
    memory[2] = 8'b00000010;
    memory[3] = 8'b00000011;
end

always @(*) begin
    case (address)
        2'b00: data = memory[0];
        2'b01: data = memory[1];
        2'b10: data = memory[2];
        2'b11: data = memory[3];
    endcase
end

endmodule

In this example, the module `ROM_example` has an input `address` which specifies the memory location to read from, and an output `data` which holds the value stored at that location. The memory array `memory` is defined using the `reg` data type, and it is initialized with specific values in the `initial` block.

Inside the `always` block, a `case` statement is used to select the appropriate memory location based on the input `address`. The corresponding data value is then assigned to the output `data`.

Keep in mind that this is a basic example, and in real-world designs, ROMs can have different sizes, data widths, and initialization methods depending on the specific requirements.