mirror of
https://github.com/mist-devel/mist-board.git
synced 2026-02-11 10:14:35 +00:00
49 lines
1.4 KiB
Verilog
49 lines
1.4 KiB
Verilog
//
|
|
// ste_joystick.v
|
|
//
|
|
// Atari STE joystick port implementation for the MiST board
|
|
// http://code.google.com/p/mist-board/
|
|
//
|
|
// Copyright (c) 2013 Till Harbaum <till@harbaum.org>
|
|
//
|
|
// This source file is free software: you can redistribute it and/or modify
|
|
// it under the terms of the GNU General Public License as published
|
|
// by the Free Software Foundation, either version 3 of the License, or
|
|
// (at your option) any later version.
|
|
//
|
|
// This source file is distributed in the hope that it will be useful,
|
|
// but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
// GNU General Public License for more details.
|
|
//
|
|
// You should have received a copy of the GNU General Public License
|
|
// along with this program. If not, see <http://www.gnu.org/licenses/>.
|
|
|
|
module ste_joystick (
|
|
// system interface
|
|
input clk,
|
|
input reset,
|
|
|
|
// cpu register interface
|
|
input [15:0] din,
|
|
input sel,
|
|
input [4:0] addr,
|
|
input uds,
|
|
input lds,
|
|
input rw,
|
|
output reg [15:0] dout
|
|
);
|
|
|
|
// no functionality implemented yet
|
|
always @(sel, rw, uds, lds, addr) begin
|
|
dout = 16'h0000;
|
|
|
|
if(sel && rw) begin
|
|
if(addr == 5'h00) dout = 16'hffff; // no fire button pressed
|
|
if(addr == 5'h01) dout = 16'hffff; // no direction set
|
|
end
|
|
|
|
end
|
|
|
|
endmodule
|