Subversion Repositories wb_lcd

//////////////////////////////////////////////////////////////////////

////                                                              ////

////  system.v                                                    ////

////                                                              ////

////  This file is part of:                                       ////

////  WISHBONE/MEM MAPPED CONTROLLER FOR LCD CHARACTER DISPLAYS   ////

////  http://www.opencores.org/projects/wb_lcd/                   ////

////                                                              ////

////  Description                                                 ////

////   - Wishbone controller testbench implementation for         ////

////     Spartan 3E Starter Kit (XC3S500E) board from Digilent.   ////

////  To Do:                                                      ////

////   - nothing really                                           ////

////                                                              ////

////  Author(s):                                                  ////

////   - José Ignacio Villar, jose@dte.us.es , jvillar@gmail.com  ////

////                                                              ////

//////////////////////////////////////////////////////////////////////

////                                                              ////

//// Copyright (C) 2009 José Ignacio Villar - jvillar@gmail.com   ////

////                                                              ////

//// This source file may be used and distributed without         ////

//// restriction provided that this copyright statement is not    ////

//// removed from the file and that any derivative work contains  ////

//// the original copyright notice and the associated disclaimer. ////

////                                                              ////

//// This source file is free software; you can redistribute it   ////

//// and/or modify it under the terms of the GNU Lesser 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 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 Lesser General Public License for more ////

//// details.                                                     ////

////                                                              ////

//// You should have received a copy of the GNU Lesser General    ////

//// Public License along with this source; if not, download it   ////

//// from http://www.gnu.org/licenses/lgpl.txt                    ////

////                                                              ////

//////////////////////////////////////////////////////////////////////

`include "lcd_defines.v"

module system(

        input clk,

        input reset,

        input  [2:0] rot,

        output [3:0] SF_D,

        output LCD_E,

        output LCD_RS,

        output LCD_RW,

        output SF_CE0,

        output reg [7:0] led

        );

//----------------------------------------------------------------------------

// rotary decoder

//----------------------------------------------------------------------------

wire rot_btn;

wire rot_event;

wire rot_left;

rotary rotdec0 (

        .clk(       clk        ),

        .reset(     reset      ),

        .rot(       rot        ),

        // output

        .rot_btn(   rot_btn    ),

        .rot_event( rot_event  ),

        .rot_left(  rot_left   )

);

//----------------------------------------------------------------------------

// LCD Display

//----------------------------------------------------------------------------

reg     [`DAT_RNG]      dat = 8'b00100000;

wire    [`WB_DAT_RNG]   wb_dat = {24'b0, dat};

reg     [`ADDR_WIDTH:0] addr = 0;

wire    [`WB_ADDR_RNG]  wb_addr = {24'b0, addr};

wire    [`WB_DAT_RNG]   status;

wire                    busy = status[0];

wire cs;

wire we;

wire ack;

wb_lcd lcd  (

        //

        // I/O Ports

        //

        .wb_clk_i       ( clk ),

        .wb_rst_i       ( reset),

        //

        // WB slave interface

        //

        .wb_dat_i       ( wb_dat ),

        .wb_dat_o       ( status ),

        .wb_adr_i       ( wb_addr ),

        .wb_sel_i       (  ),

        .wb_we_i        ( we ),

        .wb_cyc_i       ( cs  ),

        .wb_stb_i       ( cs ),

        .wb_ack_o       ( ack ),

        //

        // LCD interface

        //

        .SF_D   ( SF_D ),

        .LCD_E  ( LCD_E ),

        .LCD_RS ( LCD_RS ),

        .LCD_RW ( LCD_RW )

        );

//----------------------------------------------------------------------------

// Behavioural description

//----------------------------------------------------------------------------

assign SF_CE0 = 1'b1; // disable intel strataflash

// Handles "start displaying character" shift

reg [`DAT_RNG]  start_dat = 8'b00100000;

integer i = 0;

assign we = (i < 104) & ~busy;

assign cs = (i < 104);

// Handles transfers to the display

always @(posedge clk)

begin

        if(reset) begin

                led <= 8'b00100000;

                start_dat <= 8'b00100000;

                i <= 0;

                addr <= 0;

                dat <= start_dat;

        end else begin

                if (i < 105 && !busy) begin

                        i <= i + 1;

                        addr <= addr + 1;

                        dat <= dat + 1;

                end else if (rot_event && rot_left && !busy) begin

                        led <= led - 1;

                        start_dat <= start_dat - 1;

                        i <= 0;

                        addr <= 0;

                        dat <= start_dat - 1;

                end else if (rot_event && !busy) begin

                        led <= led + 1;

                        start_dat <= start_dat + 1;

                        i <= 0;

                        addr <= 0;

                        dat <= start_dat + 1;

                end

        end

end

endmodule