// ZX-Evo Base Configuration (c) NedoPC 2008,2009,2010,2011,2012,2013,2014
 
//
 
// just DOS signal control
 
 
 
/*
 
    This file is part of ZX-Evo Base Configuration firmware.
 
 
 
    ZX-Evo Base Configuration firmware 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.
 
 
 
    ZX-Evo Base Configuration firmware 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 ZX-Evo Base Configuration firmware.
 
    If not, see <http://www.gnu.org/licenses/>.
 
*/
 
 
 
`include "../include/tune.v"
 
 
 
module zdos(
 
 
 
        input  wire        fclk,
 
        input  wire        rst_n,
 
 
 
 
 
        input  wire        dos_turn_on,
 
        input  wire        dos_turn_off,
 
 
 
        input  wire        cpm_n,
 
 
 
 
 
        output reg         dos
 
);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
        always @(posedge fclk, negedge rst_n)
 
        if( !rst_n )
 
        begin
 
                dos = 1'b1;
 
        end
 
        else // posedge fclk
 
        begin
 
                if( !cpm_n )
 
                        dos <= 1'b1;
 
                else if( dos_turn_off )
 
                        dos <= 1'b0;
 
                else if( dos_turn_on )
 
                        dos <= 1'b1;
 
        end
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
endmodule