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////////////////////////////////////////////////////////////////////////////////
// //
// This file is placed into the Public Domain, for any use, without warranty. //
// 2012 by Iztok Jeras //
// SPDX-License-Identifier: CC0-1.0 //
// //
////////////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////////
// //
// This testbench contains a bus source and a bus drain. The source creates //
// address and data bus values, while the drain is the final destination of //
// such pairs. All source and drain transfers are logged into memories, which //
// are used at the end of simulation to check for data transfer correctness. //
// Inside the RLT wrapper there is a multiplexer and a demultiplexer, they //
// bus transfers into a 8bit data stream and back. Both stream input and //
// output are exposed, they are connected together into a loopback. //
// //
// ----------- --------------------- //
// | bso_mem | | wrap | //
// ----------- | | //
// ----------- | | ----------- | //
// | bsi src | ------------> | -> | mux | -> | -> - sto //
// ----------- | ----------- | \ //
// | | | loopback //
// ----------- | ----------- | / //
// | bso drn | <------------ | <- | demux | <- | <- - sti //
// ----------- | | ----------- | //
// ----------- | | //
// | bso_mem | | | //
// ----------- --------------------- //
// //
// PROTOCOL: //
// //
// The 'vld' signal is driven by the source to indicate valid data is //
// available, 'rdy' is used by the drain to indicate is is ready to accept //
// valid data. A data transfer only happens if both 'vld' & 'rdy' are active. //
// //
////////////////////////////////////////////////////////////////////////////////
`timescale 1ns/1ps
// include RTL files
`include "t_sv_bus_mux_demux/sv_bus_mux_demux_def.sv"
`include "t_sv_bus_mux_demux/sv_bus_mux_demux_demux.sv"
`include "t_sv_bus_mux_demux/sv_bus_mux_demux_mux.sv"
`include "t_sv_bus_mux_demux/sv_bus_mux_demux_wrap.sv"
module t (/*AUTOARG*/
// Inputs
clk
);
input clk;
parameter SIZ = 10;
// system signals
//logic clk = 1'b1; // clock
logic rst = 1'b1; // reset
integer rst_cnt = 0;
// input bus
logic bsi_vld; // valid (chip select)
logic [31:0] bsi_adr; // address
logic [31:0] bsi_dat; // data
logic bsi_rdy; // ready (acknowledge)
logic bsi_trn; // data transfer
logic [31:0] bsi_mem [SIZ];
// output stream
logic sto_vld; // valid (chip select)
logic [7:0] sto_bus; // data bus
logic sto_rdy; // ready (acknowledge)
// input stream
logic sti_vld; // valid (chip select)
logic [7:0] sti_bus; // data bus
logic sti_rdy; // ready (acknowledge)
// output bus
logic bso_vld; // valid (chip select)
logic [31:0] bso_adr; // address
logic [31:0] bso_dat; // data
logic bso_rdy; // ready (acknowledge)
logic bso_trn; // data transfer
logic [31:0] bso_mem [SIZ];
integer bso_cnt = 0;
////////////////////////////////////////////////////////////////////////////////
// clock and reset
////////////////////////////////////////////////////////////////////////////////
// clock toggling
//always #5 clk = ~clk;
// reset is removed after a delay
always @ (posedge clk)
begin
rst_cnt <= rst_cnt + 1;
rst <= rst_cnt <= 3;
end
// reset is removed after a delay
always @ (posedge clk)
if (bso_cnt == SIZ) begin
if (bsi_mem === bso_mem) begin $write("*-* All Finished *-*\n"); $finish(); end
else begin $display ("FAILED"); $stop(); end
end
////////////////////////////////////////////////////////////////////////////////
// input data generator
////////////////////////////////////////////////////////////////////////////////
// input data transfer
assign bsi_trn = bsi_vld & bsi_rdy;
// valid (for SIZ transfers)
always @ (posedge clk, posedge rst)
if (rst) bsi_vld = 1'b0;
else bsi_vld = (bsi_adr < SIZ);
// address (increments every transfer)
always @ (posedge clk, posedge rst)
if (rst) bsi_adr <= 32'h00000000;
else if (bsi_trn) bsi_adr <= bsi_adr + 'd1;
// data (new random value generated after every transfer)
always @ (posedge clk, posedge rst)
if (rst) bsi_dat <= 32'h00000000;
else if (bsi_trn) bsi_dat <= $random();
// storing transferred data into memory for final check
always @ (posedge clk)
if (bsi_trn) bsi_mem [bsi_adr] <= bsi_dat;
////////////////////////////////////////////////////////////////////////////////
// RTL instance
////////////////////////////////////////////////////////////////////////////////
sv_bus_mux_demux_wrap wrap (
// system signals
.clk (clk),
.rst (rst),
// input bus
.bsi_vld (bsi_vld),
.bsi_adr (bsi_adr),
.bsi_dat (bsi_dat),
.bsi_rdy (bsi_rdy),
// output stream
.sto_vld (sto_vld),
.sto_bus (sto_bus),
.sto_rdy (sto_rdy),
// input stream
.sti_vld (sti_vld),
.sti_bus (sti_bus),
.sti_rdy (sti_rdy),
// output bus
.bso_vld (bso_vld),
.bso_adr (bso_adr),
.bso_dat (bso_dat),
.bso_rdy (bso_rdy)
);
// stream output from mux is looped back into stream input for demux
assign sti_vld = sto_vld;
assign sti_bus = sto_bus;
assign sto_rdy = sti_rdy;
////////////////////////////////////////////////////////////////////////////////
// output data monitor
////////////////////////////////////////////////////////////////////////////////
// input data transfer
assign bso_trn = bso_vld & bso_rdy;
// output transfer counter used to end the test
always @ (posedge clk, posedge rst)
if (rst) bso_cnt <= 0;
else if (bso_trn) bso_cnt <= bso_cnt + 1;
// storing transferred data into memory for final check
always @ (posedge clk)
if (bso_trn) bso_mem [bso_adr] <= bso_dat;
// every output transfer against expected value stored in memory
always @ (posedge clk)
if (bso_trn && (bsi_mem [bso_adr] !== bso_dat))
$display ("@%08h i:%08h o:%08h", bso_adr, bsi_mem [bso_adr], bso_dat);
// ready is active for SIZ transfers
always @ (posedge clk, posedge rst)
if (rst) bso_rdy = 1'b0;
else bso_rdy = 1'b1;
endmodule
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