`timescale 1ns / 1ps
//////////////////////////////////////////////////////////////////////////////////
// upgineer: Bryan Orabutt
//
// Create Date:    18:07:32 12/31/2014
// Design Name:    Prototype 1
// Module Name:    LED_counter1
// Project Name:   LED Cube Project
// Target Devices: XCSLX9
// Tool versions:  ISE Web Pack 14.7
// Description:    This prototype module uses two counters to continuously blink each LED
//
// Dependupcies:
//
// Revision:
// Revision 0.01 - File Created
// Additional Commupts:
//
//////////////////////////////////////////////////////////////////////////////////
module LED_counter(
    input clk,
    output reg[1:0] level,
    output reg[3:0] column
    );

reg [3:0] counter1 = 4'b0000;
reg [1:0] counter2 = 2'b00;
wire c1_max = (counter1 == 4'b1000); //the number of columns in my cube
wire c2_max = (counter2 == 2'b10); //the number of levels in my cube

/* Counter to cycle through each column, powering one cloumn with each count
*  and resetting the count when c1_max is a logic high.
*/
always @ (posedge clk) begin
    if(c1_max)
        counter1 <= 4'b0;
    else
        counter1 <= counter1 + 1;
end

/* Counter to cycle through each level, powering the base pin of a single 2N222
*  which causes one level to be connected to GND. Combining this with the column
*  counter means one level + one column is active at a time, meaning one LED is on.
*/
always @ (posedge clk) begin
    if(c2_max && c1_max)
        counter2 <= 2'b00;
    else if(c1_max)
        counter2 <= counter2 + 1;
end

/* Connect the counter values to the output.
*/
always @ (posedge clk) begin
        column <= counter1;
        level <= counter2;
end

endmodule