User`s manual

13 input up,
14 input down,
15 input left,
16 input right,
17 input override,
18 input[1:0] switch,
19 input[9:0] x1_raw,
20 input[8:0] y1_raw,
21 input[9:0] x2_raw,
22 input[8:0] y2_raw,
23 input[9:0] x3_raw,
24 input[8:0] y3_raw,
25 input[9:0] x4_raw,
26 input[8:0] y4_raw,
27 output reg[9:0] x1,
28 output reg[8:0] y1,
29 output reg[9:0] x2,
30 output reg[8:0] y2,
31 output reg[9:0] x3,
32 output reg[8:0] y3,
33 output reg[9:0] x4,
34 output reg[8:0] y4,
35 output reg[9:0] display_x,
36 output reg[8:0] display_y);
37
38 parameter OVERRIDE = 1’b0;
39
40 parameter XSPEED = 1’d1;
41 parameter YSPEED = 1’d1;
42
43 // 640 x 480 screen
44 parameter SCR_WIDTH = 10’d639;
45 parameter SCR_HEIGHT = 9’d479;
46
47 reg cur_state = ~OVERRIDE;
48
49 always @(posedge clk) begin
50 case (switch)
51 2’b00: begin
52 display_x <= x1;
53 display_y <= y1;
54 end
55 2’b01: begin
56 display_x <= x2;
57 display_y <= y2;
58 end
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