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writing-module

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Provides module template with include guard, port ordering, and checklist. Triggers when creating a new svc_ module from scratch.

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Writing a New Module

Module Template

`ifndef SVC_MODULE_NAME_SV
`define SVC_MODULE_NAME_SV

`include "svc.sv"

module svc_module_name #(
    parameter WIDTH = 32
) (
    input  logic             clk,
    input  logic             rst_n,

    input  logic             in_valid,
    input  logic [WIDTH-1:0] in_data,
    output logic             in_ready,

    output logic             out_valid,
    output logic [WIDTH-1:0] out_data,
    input  logic             out_ready
);
  //
  // Localparams
  //

  //
  // Internal signals
  //
  logic [WIDTH-1:0] data_next;

  //
  // Child module instantiations
  //

  //
  // Combinational logic
  //
  always_comb begin
    data_next = in_data;
  end

  //
  // Sequential logic
  //
  always_ff @(posedge clk) begin
    if (!rst_n) begin
      out_valid <= 1'b0;
      out_data  <= '0;
    end else begin
      // Logic here
    end
  end

endmodule

`endif

Checklist

  • Include guard with _SV suffix (uppercase module name)
  • include "svc.sv" after guard
  • Module name has svc_ prefix
  • Ports: clk, rst_n first
  • Parameters before ports
  • Group related ports with blank lines
  • Align port declarations
  • Comments above code, never at end of line
  • Use blank comment blocks for section separators
  • Run make format when done
  • Run make lint before committing

File Location

Place in appropriate rtl/ subdirectory:

  • rtl/axi/ - AXI/AXI-Lite
  • rtl/cdc/ - Clock domain crossing
  • rtl/common/ - Fundamental building blocks
  • rtl/fifo/ - FIFOs
  • rtl/gfx/ - Graphics/VGA
  • rtl/ice40/ - iCE40 FPGA-specific
  • rtl/rv/ - RISC-V processor
  • rtl/stats/ - Statistics collection
  • rtl/uart/ - Serial communication

Reference Implementation

See rtl/common/svc_arbiter.sv for a well-structured example.