105 lines
3.8 KiB
VHDL
Executable File
105 lines
3.8 KiB
VHDL
Executable File
library ieee;
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use ieee.std_logic_1164.all;
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use ieee.numeric_std.all;
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use ieee.std_logic_unsigned.all;
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use ieee.math_real.all;
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--
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-- Copyright (C) 2007, Peter C. Wallace, Mesa Electronics
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-- http://www.mesanet.com
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--
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-- This program is is licensed under a disjunctive dual license giving you
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-- the choice of one of the two following sets of free software/open source
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-- licensing terms:
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--
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-- * GNU General Public License (GPL), version 2.0 or later
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-- * 3-clause BSD License
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--
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--
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-- The GNU GPL License:
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--
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-- This program is free software; you can redistribute it and/or modify
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-- it under the terms of the GNU General Public License as published by
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-- the Free Software Foundation; either version 2 of the License, or
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-- (at 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,
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-- but WITHOUT ANY WARRANTY; without even the implied warranty of
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-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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-- GNU General Public License for more details.
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--
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-- You should have received a copy of the GNU General Public License
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-- along with this program; if not, write to the Free Software
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-- Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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--
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--
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-- The 3-clause BSD License:
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--
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-- Redistribution and use in source and binary forms, with or without
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-- modification, are permitted provided that the following conditions
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-- are met:
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--
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-- * Redistributions of source code must retain the above copyright
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-- notice, this list of conditions and the following disclaimer.
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--
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-- * Redistributions in binary form must reproduce the above
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-- copyright notice, this list of conditions and the following
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-- disclaimer in the documentation and/or other materials
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-- provided with the distribution.
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--
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-- * Neither the name of Mesa Electronics nor the names of its
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-- contributors may be used to endorse or promote products
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-- derived from this software without specific prior written
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-- permission.
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--
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--
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-- Disclaimer:
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--
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-- THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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-- "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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-- LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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-- FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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-- COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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-- INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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-- BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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-- LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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-- CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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-- LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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-- ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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-- POSSIBILITY OF SUCH DAMAGE.
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--
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entity rcpwmrate is
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generic ( clock : integer);
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port ( clk : in std_logic;
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ibus : in std_logic_vector (31 downto 0);
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loaddivisor : in std_logic;
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rateout : out std_logic);
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end rcpwmrate;
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architecture Behavioral of rcpwmrate is
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constant defaultdivisor : real := round((real(clock)/50.0)) -2.0; -- default 50 hz
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signal divisor: std_logic_vector(31 downto 0) := std_logic_vector(to_unsigned(integer(defaultdivisor),32));
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signal count: std_logic_vector (31 downto 0);
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alias countmsb: std_logic is count(31);
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begin
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arcpwmrate: process (clk,count)
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begin
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report("rcpwm divisor: "& real'image(defaultdivisor));
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if rising_edge(clk) then
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if countmsb= '0' then
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count <= count -1;
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else
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count <= divisor;
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end if;
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if loaddivisor = '1' then
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divisor <= ibus;
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end if;
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end if; -- clk
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rateout <= countmsb;
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end process;
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end Behavioral;
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