`timescale 1ns / 1ps////////////////////////////////////////////////////////////////////////////////// Company:        Xilinx//// Create Date:    11:48:23 03/05/07// Design Name:    Stopwatch// Module Name:    time_cnt// Project Name:   ISE In Depth Tutorial// Target Device:  xc3sA700-fg484// Tool versions:  ISE 9.1i// Description://// Dependencies:// // Revision:// Revision 0.01 - File Created// Additional Comments:// ////////////////////////////////////////////////////////////////////////////////module time_cnt(ce,clk,clr,load,up,q,hundredths,tenths,sec_lsb,sec_msb,minutes);   	input		ce;           input    clk;          input    clr;          input    load;		     input    up;		     input    [19:0] q;            output [3:0] hundredths;   output [3:0] tenths;       output [3:0] sec_lsb;      output [3:0] sec_msb;      output [3:0] minutes;     reg [3:0] hundredths_cnt;  reg [3:0]	tenths_cnt;  reg [3:0] ones_cnt;  reg [3:0]	tens_cnt;  reg [3:0] mins_cnt;  wire enable, tc_1up, tc_2up, tc_3up, tc_4up, tc_5up;  wire tc_1dn, tc_2dn, tc_3dn, tc_4dn, tc_5dn;   // assigning terminal counts  assign tc_1up = (up && (hundredths_cnt == 4'd9));  assign tc_1dn = (~(up) && (hundredths_cnt == 4'd0));   assign tc_2up = (up && (tenths_cnt == 4'd9));  assign tc_2dn = (~(up) && (tenths_cnt == 4'd0));  assign tc_3up = (up && (ones_cnt == 4'd9));  assign tc_3dn = (~(up) && (ones_cnt == 4'd0));  assign tc_4up = (up && (tens_cnt == 4'd5));  assign tc_4dn = (~(up) && (tens_cnt == 4'd0));  assign tc_5up = (up && (mins_cnt == 4'd9));  assign tc_5dn = (~(up) && (mins_cnt == 4'd0));  assign enable = ~((tc_1up && tc_2up && tc_3up && tc_4up && tc_5up) ||					 (tc_1dn && tc_2dn && tc_3dn && tc_4dn && tc_5dn)) && ce;  always @(posedge clk or posedge clr)  // hundredths of seconds count  begin    if (clr)      hundredths_cnt <= 0;	 else	if  (load)       hundredths_cnt <= q[3:0];    else if (enable)        if (up)  // count up            if (hundredths_cnt == 4'd9)				 hundredths_cnt <= 4'd0;			 else hundredths_cnt <= hundredths_cnt + 1;       else  // count down            if (hundredths_cnt == 4'd0)					hundredths_cnt <= 4'd9;				else hundredths_cnt <= hundredths_cnt - 1;  end //always     always @(posedge clk or posedge clr)  //tenths of seconds count  begin    if (clr)      tenths_cnt <= 0;	 else	if  (load)       tenths_cnt <= q[7:4];    else if (enable)       if (tc_1up)// count up and hundredths TC          if (tenths_cnt == 4'd9)				 tenths_cnt <= 4'd0;			 else tenths_cnt <= tenths_cnt + 1;       else if (tc_1dn) // count down and hundredths TC            if (tenths_cnt == 4'd0)					tenths_cnt <= 4'd9;				else tenths_cnt <= tenths_cnt - 1;  end //always  // change psedge to posedge  always @(posedge clk or posedge clr)  // seconds count  begin    if (clr)      ones_cnt <= 0;	 else	if  (load)       ones_cnt <= q[11:8];    else if (enable)       if (tc_1up && tc_2up) // hundredths and tenths TC up            if (ones_cnt == 4'd9)				 ones_cnt <= 4'd0;			 else ones_cnt <= ones_cnt + 1;       else if (tc_1dn && tc_2dn) // hundredths and tenths TC down            if (ones_cnt == 4'd0)					ones_cnt <= 4'd9;				else ones_cnt <= ones_cnt - 1;  end //always    always @(posedge clk or posedge clr)  // tens of seconds count  begin    if (clr)      tens_cnt <= 0;	 else	if  (load)       tens_cnt <= q[15:12];    else if (enable)       if (tc_1up && tc_2up && tc_3up) // hundredths, tenths, and ones TC up            if (tens_cnt == 4'd5)				 tens_cnt <= 4'd0;			 else tens_cnt <= tens_cnt + 1;       else if (tc_1dn && tc_2dn && tc_3dn) // hundredths, tenths, and ones TC down          if (tens_cnt == 4'd0)				tens_cnt <= 4'd5;			 else	tens_cnt <= tens_cnt - 1;  end //always     always @(posedge clk or posedge clr)  // minutes count  begin    if (clr)      mins_cnt <= 0;	 else	if  (load)       mins_cnt <= q[19:16];    else if (enable)       if (tc_1up && tc_2up && tc_3up && tc_4up) // hundredths, tenths, ones, and tens TC up            if (mins_cnt == 4'd5)				 mins_cnt <= 4'd0;			 else mins_cnt <= mins_cnt + 1;       else if (tc_1dn && tc_2dn && tc_3dn && tc_4dn) // hundredths, tenths, ones, and tens TC down          if (mins_cnt == 4'd0)				mins_cnt <= 4'd5;			 else	mins_cnt <= mins_cnt - 1;  end //always   assign hundredths = hundredths_cnt;  assign tenths = tenths_cnt;  assign sec_lsb =  ones_cnt;  assign sec_msb = tens_cnt; //{1'b0,tens_cnt};  assign minutes = mins_cnt;endmodule