//-----------------------------------------------------------------------------//  //  Copyright (c) 2009 Xilinx Inc.////  Project  : Programmable Wave Generator//  Module   : tb_cmd_gen.v//  Parent   : tb_wave_gen//  Children : none////  Description: //    This module implements the user commands in the testbench environment.//    It is responsible for sending characters to the UUT (via the//    uart_driver), putting expected responses into the character FIFO,//    and querying and updating the internal state of the testbench (in the//    tb_ram instances), and controlling the sample checker ////  Parameters: //    STR_LEN          : Maximum length of strings////    VAR_NSAMP, VAR_PRESCALE, VAR_SPEED: Constants that correspond to the//                       nsamp, prescale, and speed locations in tb_var_ram////  Tasks://    do_cmd           : Send a command to the UUT and put the cmd/rsp pair//                       into the char_fifo. cmd & rsp are arguments. The//                       end of line (8'h0d) is added after each rsp//    write            : execute the *W command//    read             : execute the *R command//    set_nsamp//    set_speed//    set_prescale     : execute the *N, *S, *P commands//    set_var          : underlying task to support *N, *S, *P//    get_nsamp//    get_speed//    get_prescale     : execute the *n, *s, *P commands//    get_var          : underlying task to support *n, *s, *p////  Functions:////    to_dec_str       : Convert a number to a decimal string w/ leading 0s////  Internal variables:////  Notes       : //    ////  Multicycle and False Paths//    None - this is a testbench file only, and is not intended for synthesis//// All times in this testbench are expressed in units of nanoseconds, with a // precision of 1ps increments`timescale 1ns/1psmodule tb_cmd_gen ();  // No I/O//***************************************************************************// Parameter definitions//***************************************************************************  // All strings used myst be smaller than STR_LEN-1 characters to ensure that  // there is room for at least one character of zero padding (to detect the  // end of the string).  parameter  STR_LEN      = 80;    parameter  MAX_ADDR     = 1024;  parameter  ADDR_WID     = 16;  parameter  DATA_WID     = 16;  localparam VAR_NSAMP    = 0,             VAR_PRESCALE = 1,             VAR_SPEED    = 2;  localparam ACK_STR = "-OK",             ERR_STR = "-ERR";//***************************************************************************// Register declarations//***************************************************************************//***************************************************************************// Functions//***************************************************************************  function [0:5*8-1] to_dec_str;    input [DATA_WID-1:0] val;    integer i;  begin    $sformat(to_dec_str,"%d",val);    for (i=0; i<=4; i=i+1)      if (to_dec_str[8*i+:8] == " ")        to_dec_str[8*i+:8] = "0";  end  endfunction//***************************************************************************// Tasks//***************************************************************************  // The bit period is in nanoseconds since you can't pass a real to a task  task do_cmd;    input [0:STR_LEN*8-1]   cmd;    input [0:STR_LEN*8-1]   rsp;    integer                 i;  begin    // We must push the expected cmd/rsp pair into the character FIFO BEFORE    // we start sending the command to the UUT, since the UUT will start    // echoing commands as soon as they arrive.    $display("%t       Sending cmd = %s, expecting rsp = %s",             $realtime(),cmd,rsp);    // Push cmd and rsp into the char FIFO - cmd first    for (i=0; i<= STR_LEN-1; i=i+1)    begin      if (cmd[i*8+:8] != 8'h00) // Test Null and don't send it      begin        tb.tb_char_fifo_i0.push(cmd[i*8+:8]);      end // if    end // for    // Now rsp into char FIFO    for (i=0; i<= STR_LEN-1; i=i+1)    begin      if (rsp[i*8+:8] != 8'h00) // Test Null and don't send it      begin        tb.tb_char_fifo_i0.push(rsp[i*8+:8]);      end // if    end // for    tb.tb_char_fifo_i0.push(8'h0d); // Newline        // Now send the command only to the UUT    for (i=0; i<= STR_LEN-1; i=i+1)    begin      if (cmd[i*8+:8] != 8'h00) // Test Null and don't send it      begin        tb.tb_uart_driver_i0.send_char(cmd[i*8+:8]);      end // if    end // for  end  endtask  task write (    input [ADDR_WID-1:0] addr,    input [DATA_WID-1:0] val  );    reg [0:STR_LEN*8-1]  cmd, rsp;    reg                  ret;       // return code from write  begin    $sformat(cmd, "*W%x%x",addr,val);    if (addr <= MAX_ADDR) // Address is in legal range    begin       $display ("%t       Writing %x to sample address %x",                $realtime, val, addr);      ret = tb.tb_samp_ram_i0.write(addr,val);   // Update the sample RAM      // We don't care about the return code - it should always be 1)      rsp=ACK_STR;    end    else    begin      $display ("%t       Writing to illegal address %x",$realtime, addr);      rsp=ERR_STR;    end    do_cmd(cmd,rsp);  end  endtask  task read (    input [ADDR_WID-1:0]  addr  );    reg   [DATA_WID-1:0]  val;    reg   [0:5*8-1]       dec_val;    reg   [0:STR_LEN*8-1] cmd, rsp;  begin    $sformat(cmd, "*R%x",addr);    if (addr <= MAX_ADDR) // Address is in legal range    begin       val = tb.tb_samp_ram_i0.read(addr);      $display ("%t       Reading %x from sample address %x",                 $realtime, val, addr);      dec_val = to_dec_str(val);      $sformat(rsp,"-%x %s",val,dec_val);    end    else    begin      $display ("%t       Reading from illegal sample address %x",                 $realtime, addr);      rsp = ERR_STR;    end    do_cmd(cmd,rsp);  end  endtask  task set_var (    input [15:0] var,    input [15:0] val  );     reg                   ret_code;    reg   [0:STR_LEN*8-1] cmd, rsp;  begin    // Generate the command string    case (var)      VAR_NSAMP:    $sformat(cmd,"*N%h",val);      VAR_PRESCALE: $sformat(cmd,"*P%h",val);      VAR_SPEED:    $sformat(cmd,"*S%h",val);    endcase    // Attempt the variable update    ret_code = tb.tb_var_ram_i0.write(var,val);    // Generate the response    if (ret_code) // success      rsp = ACK_STR;    else      rsp = ERR_STR;    // Issue the command/response    do_cmd(cmd,rsp);  end  endtask  task set_nsamp (    input [15:0] val  );   begin    set_var(VAR_NSAMP,val);  end  endtask  task set_prescale (    input [15:0] val  );   begin    set_var(VAR_PRESCALE,val);  end  endtask  task set_speed (    input [15:0] val  );   begin    set_var(VAR_SPEED,val);  end  endtask  task get_var (    input [15:0] var  );     reg   [15:0]          val;    reg   [0:STR_LEN*8-1] cmd, rsp;    reg   [0:5*8-1]       dec_val;  begin    // Generate the command string    case (var)      VAR_NSAMP:    cmd = "*n";      VAR_PRESCALE: cmd = "*p";      VAR_SPEED:    cmd = "*s";    endcase    // Read the variable from the testbench    val = tb.tb_var_ram_i0.read(var);    // Format the response    dec_val = to_dec_str(val);    $sformat(rsp,"-%x %s",val,dec_val);    // Issue the command/response    do_cmd(cmd,rsp);  end  endtask  task get_nsamp;  begin    get_var(VAR_NSAMP);  end  endtask  task get_prescale;  begin    get_var(VAR_PRESCALE);  end  endtask  task get_speed;   begin    get_var(VAR_SPEED);  end  endtask//***************************************************************************// Code//***************************************************************************endmodule