test_pwm_sch.tfw

脉冲宽度调试机器程序设计 具体请看英文描述

////////////////////////////////////////////////////////////////////////////////
// Copyright (c) 1995-2003 Xilinx, Inc.
// All Right Reserved.
////////////////////////////////////////////////////////////////////////////////
//   ____  ____ 
//  /   /\/   / 
// /___/  \  /    Vendor: Xilinx 
// \   \   \/     Version : 7.1.04i
//  \   \         Application : ISE Foundation
//  /   /         Filename : test_pwm_sch.tfw
// /___/   /\     Timestamp : Wed Feb 21 16:11:55 2007
// \   \  /  \ 
//  \___\/\___\ 
//
//Command: 
//Design Name: test_pwm_sch
//Device: Xilinx
//
`timescale 1ns/1ps

module test_pwm_sch;
    reg CLK = 1'b0;
    reg [3:0] DATA = 4'b0000;
    reg RST = 1'b1;
    wire PWM;

    parameter PERIOD = 200;
    parameter real DUTY_CYCLE = 0.5;
    parameter OFFSET = 0;

    initial    // Clock process for CLK
    begin
        #OFFSET;
        forever
        begin
            CLK = 1'b0;
            #(PERIOD-(PERIOD*DUTY_CYCLE)) CLK = 1'b1;
            #(PERIOD*DUTY_CYCLE);
        end
    end

    pwm_sch UUT (
        .CLK(CLK),
        .DATA(DATA),
        .RST(RST),
        .PWM(PWM));

    integer TX_FILE = 0;
    integer TX_ERROR = 0;
    
    initial begin  // Open the results file...
        TX_FILE = $fopen("results.txt");
        #100200 // Final time:  100200 ns
        if (TX_ERROR == 0) begin
            $display("No errors or warnings.");
            $fdisplay(TX_FILE, "No errors or warnings.");
        end else begin
            $display("%d errors found in simulation.", TX_ERROR);
            $fdisplay(TX_FILE, "%d errors found in simulation.", TX_ERROR);
        end
        $fclose(TX_FILE);
        $stop;
    end

    initial begin
        // -------------  Current Time:  285ns
        #285;
        RST = 1'b0;
        // -------------------------------------
    end

    task CHECK_PWM;
        input NEXT_PWM;

        #0 begin
            if (NEXT_PWM !== PWM) begin
                $display("Error at time=%dns PWM=%b, expected=%b", $time, PWM, NEXT_PWM);
                $fdisplay(TX_FILE, "Error at time=%dns PWM=%b, expected=%b", $time, PWM, NEXT_PWM);
                $fflush(TX_FILE);
                TX_ERROR = TX_ERROR + 1;
            end
        end
    endtask

endmodule