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basic_verilog/soft_latch_tb.sv
2021-07-09 17:24:20 +03:00

149 lines
2.7 KiB
Systemverilog

//------------------------------------------------------------------------------
// soft_latch_tb.sv
// Konstantin Pavlov, pavlovconst@gmail.com
//------------------------------------------------------------------------------
// INFO ------------------------------------------------------------------------
// testbench for soft_latch.sv module
//
`timescale 1ns / 1ps
module soft_latch_tb();
logic clk200;
initial begin
#0 clk200 = 1'b0;
forever
#2.5 clk200 = ~clk200;
end
// external device "asynchronous" clock
logic clk33;
initial begin
#0 clk33 = 1'b0;
forever
#15.151 clk33 = ~clk33;
end
logic rst;
initial begin
#0 rst = 1'b0;
#10.2 rst = 1'b1;
#5 rst = 1'b0;
//#10000;
forever begin
#9985 rst = ~rst;
#5 rst = ~rst;
end
end
logic nrst;
assign nrst = ~rst;
logic rst_once;
initial begin
#0 rst_once = 1'b0;
#10.2 rst_once = 1'b1;
#5 rst_once = 1'b0;
end
logic nrst_once;
assign nrst_once = ~rst_once;
logic [31:0] DerivedClocks;
clk_divider #(
.WIDTH( 32 )
) cd1 (
.clk( clk200 ),
.nrst( nrst_once ),
.ena( 1'b1 ),
.out( DerivedClocks[31:0] )
);
logic [31:0] E_DerivedClocks;
edge_detect ed1[31:0] (
.clk( {32{clk200}} ),
.nrst( {32{nrst_once}} ),
.in( DerivedClocks[31:0] ),
.rising( E_DerivedClocks[31:0] ),
.falling( ),
.both( )
);
logic [15:0] RandomNumber1;
c_rand rng1 (
.clk(clk200),
.rst(rst_once),
.reseed(1'b0),
.seed_val(DerivedClocks[31:0]),
.out( RandomNumber1[15:0] )
);
logic start;
initial begin
#0 start = 1'b0;
#100 start = 1'b1;
#20 start = 1'b0;
end
// Module under test ==========================================================
logic set;
assign set = &RandomNumber1[14:12];
logic ret;
assign ret = &RandomNumber1[11:9];
// verilog hardvare latch
logic [15:0] data1;
always_latch begin
if( ret ) begin
data1[15:0] <= '0;
end else if( set ) begin
data1[15:0] <= RandomNumber1[15:0];
end
end
// soft_latch prototype
logic [15:0] data2;
set_reset_comb SR [15:0] (
.clk( {16{clk200}} ),
.nrst( {16{1'b1}} ),
.s( {16{set}} & RandomNumber1[15:0] ), //set
.r( ({16{set}} & ~RandomNumber1[15:0]) | {16{ret}} ), //rst
.q( data2[15:0] ),
.nq( )
);
// genuine soft_latch instance
logic [15:0] data3;
soft_latch #(
.WIDTH( 16 )
) SL1 (
.clk( clk200 ),
.nrst( ~ret ),
.latch( set ),
.in( RandomNumber1[15:0] ),
.out( data3[15:0] )
);
//==============================================================================
logic outputs_equal;
assign outputs_equal = ( data1[15:0] == data2[15:0] ) &&
( data1[15:0] == data3[15:0] );
logic success = 1'b1;
always_ff @(posedge clk200) begin
if( ~nrst ) begin
success <= 1'b1;
end else begin
if( ~outputs_equal ) begin
success <= 1'b0;
end
end
end
endmodule