Subversion Repositories iso7816_3_master

`timescale 1ns / 1ps

//////////////////////////////////////////////////////////////////////////////////

// Company: 

// Engineer: Sebastien Riou

// 

// Create Date:    23:57:02 08/31/2010 

// Design Name: 

// Module Name:    Counter 

// Project Name: 

// Target Devices: 

// Tool versions: 

// Description: A counter with increment and clear operation

//

// Dependencies: 

//

// Revision: 

// Revision 0.01 - File Created

// Additional Comments: 

//

//////////////////////////////////////////////////////////////////////////////////

module Counter(

    output reg [WIDTH-1:0] counter,

    output earlyMatch,

         output reg match,

         output dividedClk,

         input [DIVIDER_WIDTH-1:0] divider,      // clock divide factor

         input [WIDTH-1:0] compare,

         input inc,

         input clear,

         input [WIDTH_INIT-1:0] initVal,

         input clk,

    input nReset

    );

//parameters to override

parameter DIVIDER_WIDTH = 16;

parameter WIDTH = 8;

parameter WIDTH_INIT = 1;

wire divideBy1;

wire divMatch;

wire divRisingMatch;

wire divFallingMatch;

ClkDivider #(.DIVIDER_WIDTH(DIVIDER_WIDTH))

        clkDivider(

                .nReset(nReset),

                .clk(clk),

                .divider(divider),

                .dividedClk(dividedClk),

                .divideBy1(divideBy1),

                .match(divMatch),

                .risingMatch(divRisingMatch),

                .fallingMatch(divFallingMatch)

                );

wire [WIDTH-1:0] nextCounter = counter+1'b1;

wire doInc = divideBy1 ? inc :inc & divRisingMatch;

wire doEarlyMatch = divideBy1 ? (compare == nextCounter) : (compare == counter) & divRisingMatch;

reg earlyMatchReg;

assign earlyMatch = divideBy1 ? earlyMatchReg : doEarlyMatch;

always @(posedge clk, negedge nReset) begin

        if(~nReset) begin

                counter <= 0;//initVal;

      earlyMatchReg <= 0;

                match <= 0;

        end else begin

                if(clear) begin

                        counter <= initVal;

                end else if(doInc) begin

                        if(compare == counter)

                                counter <= initVal;

                        else

                                counter <= nextCounter;

                end

                if(doEarlyMatch)

                        earlyMatchReg <= 1;

                else begin

                        earlyMatchReg <= 0;

                end

      match <= divideBy1 ? earlyMatchReg : doEarlyMatch;

        end

end

endmodule