common/docs/reference/utils/dfferm.md

dfferm

Property	Value
Kind	module
RTL source	rtl/utils/register.sv
Availability	Synthesizable RTL

Summary

Masked-update D flip-flop with reset.

Functional Behavior

Masked-update D flip-flop with reset. Its exact parameters and ports are reproduced below from the implementation declaration.

Suitable Applications

Use as a small reusable datapath, state, coding, delay, or verification primitive.

Parameters

The declaration below is canonical; retain the RTL-enforced parameter range.

Parameter	Declaration
DATA_NUM	parameter int DATA_NUM = 2
DATA_WIDTH	parameter int DATA_WIDTH = 1
INIT_VAL	parameter [DATA_WIDTH-1:0] INIT_VAL = '1

Interface Definition

module dfferm #(
    parameter int                  DATA_NUM   = 2,
    parameter int                  DATA_WIDTH = 1,
    parameter     [DATA_WIDTH-1:0] INIT_VAL   = '1
) (
    input  logic                  clk_i,
    input  logic                  rst_n_i,
    input  logic [  DATA_NUM-1:0] en_i,
    input  logic [DATA_WIDTH-1:0] dat_i  [0:DATA_NUM-1],
    output logic [DATA_WIDTH-1:0] dat_o  [0:DATA_NUM-1]
);

Port Summary

Signal	Direction	Declaration
clk_i	input	input logic clk_i
rst_n_i	input	input logic rst_n_i
en_i	input	input logic [ DATA_NUM-1:0] en_i

Integration and Use

Keep parameter values within RTL assertions and add required clocking, reset, or CDC protection at the caller boundary.

dfferm #(
    .DATA_NUM(DATA_NUM),
    .DATA_WIDTH(DATA_WIDTH),
    .INIT_VAL(INIT_VAL)
) u_dfferm (
    .clk_i(clk_i),
    .rst_n_i(rst_n_i),
    .en_i(en_i)
);

Dependencies and Verification

The linked RTL source is the implementation authority and contains local assertions for unsupported parameter combinations. See docs/design.md for repository-wide CDC, reset, stream, and storage contracts, and docs/verification.md for the verification matrix.