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[/] [s6soc/] [trunk/] [rtl/] [wbgpio.v] - Blame information for rev 46

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1 7 dgisselq
////////////////////////////////////////////////////////////////////////////////
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//
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// Filename:    wbgpio.v
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//
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// Project:     CMod S6 System on a Chip, ZipCPU demonstration project
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//
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// Purpose:     A General Purpose Input/Output controller.  This controller 
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//              allows a user to read the current state of the 16-GPIO input
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//      pins, or to set the state of the 16-GPIO output pins. Specific numbers
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//      of pins are configurable from 1-16.
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//
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//      Unlike other controllers, this controller offers no capability to
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//      change input/output direction, or to implement pull-up or pull-down
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//      resistors.  It simply changes and adjusts the values going out the
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//      output pins, while allowing a user to read the values on the input
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//      pins.
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//
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//      Any change of an input pin value will result in the generation of an
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//      interrupt signal.
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//
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// Creator:     Dan Gisselquist, Ph.D.
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//              Gisselquist Technology, LLC
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//
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////////////////////////////////////////////////////////////////////////////////
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//
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// Copyright (C) 2015-2016, Gisselquist Technology, LLC
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//
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// This program is free software (firmware): you can redistribute it and/or
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// modify it under the terms of  the GNU General Public License as published
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// by the Free Software Foundation, either version 3 of the License, or (at
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// your option) 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 MERCHANTIBILITY or
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// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
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// for 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.  (It's in the $(ROOT)/doc directory, run make with no
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// target there if the PDF file isn't present.)  If not, see
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// <http://www.gnu.org/licenses/> for a copy.
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//
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// License:     GPL, v3, as defined and found on www.gnu.org,
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//              http://www.gnu.org/licenses/gpl.html
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//
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//
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////////////////////////////////////////////////////////////////////////////////
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//
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//
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module wbgpio(i_clk, i_wb_cyc, i_wb_stb, i_wb_we, i_wb_data, o_wb_data,
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                i_gpio, o_gpio, o_int);
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        parameter       NIN=16, NOUT=16, DEFAULT=16'h00;
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        input                   i_clk;
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        //
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        input                   i_wb_cyc, i_wb_stb, i_wb_we;
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        input           [31:0]   i_wb_data;
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        output  wire    [31:0]   o_wb_data;
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        //
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        input           [(NIN-1):0]      i_gpio;
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        output  reg     [(NOUT-1):0]     o_gpio;
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        //
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        output  reg             o_int;
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        // 9LUT's, 16 FF's
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        always @(posedge i_clk)
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                if ((i_wb_stb)&&(i_wb_we))
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                        o_gpio <= ((o_gpio)&(~i_wb_data[(NOUT+16-1):16]))
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                                |((i_wb_data[(NOUT-1):0])&(i_wb_data[(NOUT+16-1):16]));
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        reg     [(NIN-1):0]      x_gpio, r_gpio;
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        // 3 LUTs, 33 FF's
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        always @(posedge i_clk)
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        begin
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                x_gpio <= i_gpio;
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                r_gpio <= x_gpio;
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                o_int  <= (x_gpio != r_gpio);
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        end
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        assign  o_wb_data = { {(16-NIN){1'b0}}, r_gpio,
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                                        {(16-NOUT){1'b0}}, o_gpio };
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endmodule

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