/* lauta5 - Test for Mefisto Board through User Extension Port and Interface. */

module lauta5(CLK,PB_IN,SW_IN,BCOL_IN,BCOL_OUT,BROW,LED_OUT);
input CLK;
input [3:0] PB_IN;
input [7:0] SW_IN;
input [7:0] BCOL_IN;
output [7:0] BCOL_OUT;
output [7:0] BROW;
output [7:0] LED_OUT;

reg [7:0] USR1IN = 8'b0;
reg [7:0] USR1OUT = 8'b0;

// The multiplexed row, one-hot in 8-bit shift register:
reg [7:0] sel_row = 8'b00000001;

// 50 MHz/50Hz = 1 million ~= 2^20
parameter msb = 15; // Use 26; for a little over second.
reg [msb:0] delay_counter = 0;
parameter kuuw = 2;
wire [kuuw:0] kuu = delay_counter[msb:msb-kuuw];

// We turn the 1/8th time the row signals completely off
// (after switch from one row to next), so that we don't
// get dim, but superfluous "pre-" and "afterglows" below and
// on the top of each LED that should glow.
// (This because the slowness of the optoisolators
//  in the interface module).

assign BROW = ((~|kuu) ? 8'b00000000 : sel_row);

// assign BCOL_OUT = ~BCOL_IN;
assign BCOL_OUT = USR1IN;
assign LED_OUT = {USR1IN[0],USR1IN[1],USR1IN[2],USR1IN[3],USR1IN[4],USR1IN[5],USR1IN[6],USR1IN[7]};

always @(posedge CLK)
  begin
   delay_counter <= delay_counter+1; // Wraps around, eventually.
   USR1IN  <= ~BCOL_IN;
   USR1OUT <= {SW_IN[0],SW_IN[1],SW_IN[2],SW_IN[3],SW_IN[4],SW_IN[5],SW_IN[6],SW_IN[7]};
// USR1OUT[3:0] <= {PB_IN[0],PB_IN[1],PB_IN[2],PB_IN[3]};
// USR1OUT[7:4] <= {PB_IN[0],PB_IN[1],PB_IN[2],PB_IN[3]};
   if(0 == delay_counter)
     sel_row <= {sel_row[6],sel_row[5],sel_row[4],sel_row[3],sel_row[2],sel_row[1],sel_row[0],sel_row[7]};
  end

endmodule