// Example program for rle encoder
module rle
   (input clk,
    input reset,
    input [6:0] inChar,
    output [7:0] outChar,
    output reg 	     valid);

   reg 		     selCnt, clr, tag;
   reg [6:0] 	     char;
   reg [7:0] 	     count;
   always @(posedge clk) begin
      char <= inChar;
   end
   always @(posedge clk) begin
      if (clr) count <= 0;
      else count <= count + 1;
   end
   assign outChar = selCnt ? count : { tag, char };
   wire equal = inChar == char;

   localparam START=0, NOTEQUAL=1, EQUAL=2 ;
   reg [1:0] state, nxtState;
   always @(posedge clk) begin
      if (reset) begin
	 state <= START;
      end else begin
	 state <= nxtState;
      end
   end
   always @(*) begin
      nxtState = state;
      case (state) 
	START: begin
	   {tag, selCnt, clr, valid} = 4'bxxx0;
	   nxtState = NOTEQUAL;
	end
	NOTEQUAL: begin
	   if (equal) begin
	      {tag, selCnt, clr, valid} = 4'b1011;
	      nxtState = EQUAL;
	   end else begin
	      {tag, selCnt, clr, valid} = 4'b00x1;
	      nxtState = NOTEQUAL;
	   end
	end
	EQUAL: begin
	   if (equal) begin
	      {tag, selCnt, clr, valid} = 4'bxx00;
	      nxtState = EQUAL;
	   end else begin
	      {tag, selCnt, clr, valid} = 4'bx1x1;
	      nxtState = NOTEQUAL;
	   end
	end
	default: begin
	   {tag, selCnt, clr, valid} = 4'bxxxx;
	end
      endcase // case (state)
   end // always @ (*)
endmodule //