PS2Button.v

   1 module PS2Button(
   2         input inclk,
   3         input indata,
   4         output wire [7:0] buttons
   5         );
   6
   7         reg [3:0] bitcount = 0;
   8         reg [7:0] key = 0;
   9         reg keyarrow = 0, keyup = 0, parity = 0;
  10         reg key_a = 0,key_b = 0,key_st = 0,key_sel = 0,key_up = 0,key_dn = 0,key_l = 0,key_r = 0;
  11
  12         assign buttons = {key_st,key_sel,key_b,key_a,key_dn,key_up,key_l,key_r};
  13
  14         always @ (negedge inclk) begin
  15                 if(bitcount == 10) begin
  16                         bitcount <= 0;
  17                         if(parity != (^ key)) begin
  18                                 if(keyarrow) begin
  19                                         keyarrow <= 0;
  20                                         case(key)
  21                                                 8'hF0: keyup <= 1;
  22                                                 8'h75: key_up <= 1;
  23                                                 8'h74: key_r <= 1;
  24                                                 8'h72: key_dn <= 1;
  25                                                 8'h6B: key_l <= 1;
  26                                         endcase
  27                                 end
  28                                 else begin
  29                                         if(keyup) begin
  30                                                 keyup <= 0;
  31                                                 case(key)
  32                                                         8'h75: key_up <= 0;
  33                                                         8'h74: key_r <= 0;
  34                                                         8'h72: key_dn <= 0;
  35                                                         8'h6B: key_l <= 0;
  36                                                         8'h1C: key_a <= 0;
  37                                                         8'h1B: key_b <= 0;
  38                                                         8'h5A: key_st <= 0;
  39                                                         8'h59: key_sel <= 0;
  40                                                 endcase
  41                                         end
  42                                         else begin
  43                                                 case(key)
  44                                                         8'hE0: keyarrow <= 1;
  45                                                         8'hF0: keyup <= 1;
  46                                                         8'h1C: key_a <= 1;
  47                                                         8'h1B: key_b <= 1;
  48                                                         8'h5A: key_st <= 1;
  49                                                         8'h59: key_sel <= 1;
  50                                                 endcase
  51                                         end
  52                                 end
  53                         end
  54                         else begin
  55                                 keyarrow <= 0;
  56                                 keyup <= 0;
  57                                 {key_a,key_b,key_st,key_sel,key_up,key_dn,key_l,key_r} <= 8'b0;
  58                         end
  59                 end else
  60                         bitcount <= bitcount + 1;
  61
  62                 case(bitcount)
  63                         1: key[0] <= indata;
  64                         2: key[1] <= indata;
  65                         3: key[2] <= indata;
  66                         4: key[3] <= indata;
  67                         5: key[4] <= indata;
  68                         6: key[5] <= indata;
  69                         7: key[6] <= indata;
  70                         8: key[7] <= indata;
  71                         9: parity <= indata;
  72                 endcase
  73         end
  74
  75 endmodule