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How to use the include command in verilog to use another sub-circuit in the same project?

General • Asked about 2 months ago by Cesar Andrey Perdomo

Gravatar Cesar Andrey Perdomo Commented on Nov 30, 2020:


Subcircuit verilog Halfadder

module HalfAdder (a,b,s,c);
input a,b;
output s,c;
wire nand_2_out_0,nand_3_out_0,nand_0_out_0,not_0_out_0,nand_1_out_0;
nand nand_2 (nand_2_out_0,nand_0_out_0,b);
nand nand_3 (nand_3_out_0,nand_1_out_0,nand_2_out_0);
assign s = nand_3_out_0;
nand nand_0 (nand_0_out_0,a,b);
not not_0 (not_0_out_0,nand_0_out_0);
assign c = not_0_out_0;
nand nand_1 (nand_1_out_0,a,nand_0_out_0);

Sub-circuit verilog Fulladder

include HalfAdder ???

module FullAdder (a,b,cin,s,cout);
input a,b,cin;
output s,cout;
wire HalfAdder_0_out_0,HalfAdder_0_out_1,HalfAdder_1_out_0,HalfAdder_1_out_1,or_0_out_0;
HalfAdder HalfAdder_0 (a,b,HalfAdder_0_out_0,HalfAdder_0_out_1);
HalfAdder HalfAdder_1 (HalfAdder_0_out_0,cin,HalfAdder_1_out_0,HalfAdder_1_out_1);
or or_0 (or_0_out_0,HalfAdder_1_out_1,HalfAdder_0_out_1);
assign cout = or_0_out_0;
assign s = HalfAdder_1_out_0;

Gravatar Satvik Ramaprasad Commented on Dec 03, 2020:

Cesar, simply include both modules in one file. It figures out which is the root module automatically.

For example, this will work:

// Half adder
module halfadder(
input a,
input b,
output o,
output c

assign o = a ^ b;
assign c = a & b;


// Full adder
module fulladder(
input a,
input b,
input d,
output o,
output c

logic t, c1, c2;

halfadder ha1(a, b, t, c1);
halfadder ha2(t, d, o, c2);

assign c = c1 | c2;