PS2Button.v

   1 module PS2Button(
   2         input inclk,
   3         input indata,
   4         input rst,
   5         output outclk,
   6         output outdata,
   7         output reg [7:0] buttons
   8         );
   9
  10         assign outdata = 1'b1;
  11         assign outclk = 1'b1;
  12
  13         reg bitcount [3:0] = 0;
  14         reg [7:0] key;
  15         reg keyarrow, keyup, parity;
  16         reg key_a,key_b,key_st,key_sel,key_up,key_dn,key_l,key_r;
  17
  18         assign buttons = {key_st,key_sel,key_b,key_a,key_dn,key_up,key_l,key_r};
  19
  20         always @ (negedge inclk) begin
  21                 if(bitcount == 10) begin
  22                         bitcount <= 0;
  23                         if(parity == (^ key)) begin
  24                                 if(keyarrow) begin
  25                                         keyarrow <= 0;
  26                                         case(key)
  27                                                 8'hF0: keyup <= 1;
  28                                                 8'h75: key_up <= 1;
  29                                                 8'h74: key_r <= 1;
  30                                                 8'h72: key_dn <= 1;
  31                                                 8'h6B: key_l <= 1;
  32                                         endcase
  33                                 end
  34                                 else begin
  35                                         if(keyup) begin
  36                                                 keyup <= 0;
  37                                                 case(key)
  38                                                         8'h75: key_up <= 0;
  39                                                         8'h74: key_r <= 0;
  40                                                         8'h72: key_dn <= 0;
  41                                                         8'h6B: key_l <= 0;
  42                                                         8'h1C: key_a <= 0;
  43                                                         8'h1B: key_b <= 0;
  44                                                         8'h5A: key_st <= 0;
  45                                                         8'h59: key_sel <= 0;
  46                                                 endcase
  47                                         end
  48                                         else begin
  49                                                 case(key)
  50                                                         8'hE0: keyarrow <= 1;
  51                                                         8'hF0: keyup <= 1;
  52                                                         8'h1C: key_a <= 1;
  53                                                         8'h1B: key_b <= 1;
  54                                                         8'h5A: key_st <= 1;
  55                                                         8'h59: key_sel <= 1;
  56                                                 endcase
  57                                         end
  58                                 end
  59                         end
  60                         else begin
  61                                 keyarrow <= 0;
  62                                 keyup <= 0;
  63                                 {key_a,key_b,key_st,key_sel,key_up,key_dn,key_l,key_r} <= 8'b0;
  64                         end
  65                 end else
  66                         bitcount <= bitcount + 1;
  67
  68                 case(bitcount)
  69                         1: key[0] <= indata;
  70                         2: key[1] <= indata;
  71                         3: key[2] <= indata;
  72                         4: key[3] <= indata;
  73                         5: key[4] <= indata;
  74                         6: key[5] <= indata;
  75                         7: key[6] <= indata;
  76                         8: key[7] <= indata;
  77                         9: parity <= indata;
  78                 endcase
  79         end
  80
  81 endmodule