KEYPAD Scanner 4x4 cpld

module keypadscan(reset, 
                  clk, 
                  row, 
                  column, 
                  out);
   // program for 4x3 keypad
   input  reset, clk;
   output [3:0] row; 
   input  [2:0] column; //pullup to vcc 
   output [3:0] out;    //decoded output

   reg  [3:0]  row;
   reg  [3:0]  out;

   wire        scan_en = &column;
   
   //scanning keypad
   always @(posedge clk or posedge reset)
     if (reset) 
       row <= 4'b1110;
     else if (scan_en)
       row <= {row[2:0], row[3]};
   
               
   always @(row or column) begin
      out = 4'b0000;
      case ({row,column})
        7'b1110_110 : out = 4'b0001;
        7'b1110_101 : out = 4'b0010;
        7'b1110_011 : out = 4'b0011;
        
        7'b1101_110 : out = 4'b0100;
        7'b1101_101 : out = 4'b0101;
        7'b1101_011 : out = 4'b0110;
        
        7'b1011_110 : out = 4'b0111;
        7'b1011_101 : out = 4'b1000;
        7'b1011_011 : out = 4'b1001;
        
        7'b0111_110 : out = 4'b1110; // decode as E
        7'b0111_101 : out = 4'b0000;
        7'b0111_011 : out = 4'b1111; // decode as F
      endcase // case({row,column})
   end // always @ (row or column)
endmodule // keypadscan