Fix some flag bugs in INC and DEC
[fpgaboy.git] / PS2Button.v
1 module PS2Button(
2         input clk,
3         input inclk,
4         input indata,
5         output wire [7:0] buttons
6         );
7
8         reg [3:0] bitcount = 0;
9         reg [7:0] key = 0;
10         reg keyarrow = 0, keyup = 0, parity = 0;
11         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;
12
13         assign buttons = {key_st,key_sel,key_b,key_a,key_dn,key_up,key_l,key_r};
14         
15         /* Clock debouncing */
16         reg lastinclk = 0;
17         reg [5:0] debounce = 0;
18         reg fixedclk = 0;
19         reg [9:0] resetcountdown = 0;
20         
21         always @(posedge clk) begin
22                 if (inclk != lastinclk) begin
23                         lastinclk <= inclk;
24                         debounce <= 1;
25                         resetcountdown <= 10'b1111111111;
26                 end else if (debounce == 0) begin
27                         fixedclk <= inclk;
28                         resetcountdown <= resetcountdown - 1;
29                 end else
30                         debounce <= debounce + 1;
31         end
32
33         always @(negedge fixedclk) begin
34                 if (resetcountdown == 0)
35                         bitcount <= 0;
36                 else if (bitcount == 10) begin
37                         bitcount <= 0;
38                         if(parity != (^ key)) begin
39                                 if(keyarrow) begin
40                                         keyarrow <= 0;
41                                         case(key)
42                                                 8'hF0: keyup <= 1;
43                                                 8'h75: key_up <= 1;
44                                                 8'h74: key_r <= 1;
45                                                 8'h72: key_dn <= 1;
46                                                 8'h6B: key_l <= 1;
47                                         endcase
48                                 end
49                                 else begin
50                                         if(keyup) begin
51                                                 keyup <= 0;
52                                                 case(key)
53                                                         8'h75: key_up <= 0;
54                                                         8'h74: key_r <= 0;
55                                                         8'h72: key_dn <= 0;
56                                                         8'h6B: key_l <= 0;
57                                                         8'h1C: key_a <= 0;
58                                                         8'h1B: key_b <= 0;
59                                                         8'h5A: key_st <= 0;
60                                                         8'h59: key_sel <= 0;
61                                                 endcase
62                                         end
63                                         else begin
64                                                 case(key)
65                                                         8'hE0: keyarrow <= 1;
66                                                         8'hF0: keyup <= 1;
67                                                         8'h1C: key_a <= 1;
68                                                         8'h1B: key_b <= 1;
69                                                         8'h5A: key_st <= 1;
70                                                         8'h59: key_sel <= 1;
71                                                 endcase
72                                         end
73                                 end
74                         end
75                         else begin
76                                 keyarrow <= 0;
77                                 keyup <= 0;
78                                 {key_a,key_b,key_st,key_sel,key_up,key_dn,key_l,key_r} <= 8'b0;
79                         end
80                 end else
81                         bitcount <= bitcount + 1;
82
83                 case(bitcount)
84                         1: key[0] <= indata;
85                         2: key[1] <= indata;
86                         3: key[2] <= indata;
87                         4: key[3] <= indata;
88                         5: key[4] <= indata;
89                         6: key[5] <= indata;
90                         7: key[6] <= indata;
91                         8: key[7] <= indata;
92                         9: parity <= indata;
93                 endcase
94         end
95
96 endmodule
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