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67 lines
1.8 KiB
Verilog
67 lines
1.8 KiB
Verilog
////////////////////////////////////////////////////////////////////////////////
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//
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// PS2-to-Kempston Mouse v2
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// (C) 2017,2018 Sorgelig
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//
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// This program is free software; you can redistribute it and/or modify it
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// under the terms of the GNU General Public License as published by the Free
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// Software Foundation; either version 2 of the License, or (at your option)
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// any later version.
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//
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// This program is distributed in the hope that it will be useful, but WITHOUT
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// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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// FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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// more details.
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//
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// You should have received a copy of the GNU General Public License along
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// with this program; if not, write to the Free Software Foundation, Inc.,
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// 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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//
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////////////////////////////////////////////////////////////////////////////////
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module kempston_mouse
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(
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input clk_sys,
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input reset,
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input [24:0] ps2_mouse,
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input [2:0] addr,
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output sel,
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output [7:0] dout
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);
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assign dout = data;
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assign sel = port_sel;
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reg [11:0] dx;
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reg [11:0] dy;
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reg [7:0] data;
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reg port_sel;
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always @* begin
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port_sel = 1;
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casex(addr)
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3'b011: data = dx[7:0];
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3'b111: data = dy[7:0];
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3'bX10: data = ~{5'b00000,ps2_mouse[2], ps2_mouse[0], ps2_mouse[1]} ;
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default: {port_sel,data} = 8'hFF;
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endcase
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end
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always @(posedge clk_sys) begin
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reg old_status;
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old_status <= ps2_mouse[24];
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if(reset) begin
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dx <= 128; // dx != dy for better mouse detection
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dy <= 0;
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end
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else if(old_status != ps2_mouse[24]) begin
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dx <= dx + {{4{ps2_mouse[4]}},ps2_mouse[15:8]};
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dy <= dy + {{4{ps2_mouse[5]}},ps2_mouse[23:16]};
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end
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end
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endmodule
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