107 lines
3.8 KiB
VHDL
Executable File
107 lines
3.8 KiB
VHDL
Executable File
library ieee;
|
|
use ieee.std_logic_1164.all;
|
|
use ieee.numeric_std.all;
|
|
use ieee.std_logic_unsigned.all;
|
|
use ieee.math_real.all;
|
|
--
|
|
-- Copyright (C) 2007, Peter C. Wallace, Mesa Electronics
|
|
-- http://www.mesanet.com
|
|
--
|
|
-- This program is is licensed under a disjunctive dual license giving you
|
|
-- the choice of one of the two following sets of free software/open source
|
|
-- licensing terms:
|
|
--
|
|
-- * GNU General Public License (GPL), version 2.0 or later
|
|
-- * 3-clause BSD License
|
|
--
|
|
--
|
|
-- The GNU GPL License:
|
|
--
|
|
-- This program 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 2 of the License, or
|
|
-- (at your option) any later version.
|
|
--
|
|
-- This program 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, write to the Free Software
|
|
-- Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
|
|
--
|
|
--
|
|
-- The 3-clause BSD License:
|
|
--
|
|
-- Redistribution and use in source and binary forms, with or without
|
|
-- modification, are permitted provided that the following conditions
|
|
-- are met:
|
|
--
|
|
-- * Redistributions of source code must retain the above copyright
|
|
-- notice, this list of conditions and the following disclaimer.
|
|
--
|
|
-- * Redistributions in binary form must reproduce the above
|
|
-- copyright notice, this list of conditions and the following
|
|
-- disclaimer in the documentation and/or other materials
|
|
-- provided with the distribution.
|
|
--
|
|
-- * Neither the name of Mesa Electronics nor the names of its
|
|
-- contributors may be used to endorse or promote products
|
|
-- derived from this software without specific prior written
|
|
-- permission.
|
|
--
|
|
--
|
|
-- Disclaimer:
|
|
--
|
|
-- THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
|
|
-- "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
|
|
-- LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
|
|
-- FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
|
|
-- COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
|
|
-- INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
|
|
-- BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
|
|
-- LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
|
|
-- CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
-- LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
|
|
-- ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
|
|
-- POSSIBILITY OF SUCH DAMAGE.
|
|
--
|
|
|
|
entity rcpwmgen is
|
|
port ( clk : in std_logic;
|
|
ibus : in std_logic_vector (16 downto 0);
|
|
loadwidth : in std_logic;
|
|
ratein: in std_logic;
|
|
pwmout : out std_logic);
|
|
end rcpwmgen;
|
|
|
|
architecture Behavioral of rcpwmgen is
|
|
signal width: std_logic_vector(16 downto 0) := "00000000000000000";
|
|
signal count: std_logic_vector(16 downto 0);
|
|
alias countmsb: std_logic is count(16);
|
|
signal prescale: std_logic_vector(3 downto 0);
|
|
begin
|
|
arcpwmgen: process (clk,count,prescale)
|
|
begin
|
|
if rising_edge(clk) then
|
|
prescale <= prescale -1;
|
|
if prescale = 0 then
|
|
if countmsb= '0' then
|
|
count <= count -1;
|
|
end if;
|
|
end if;
|
|
if ratein = '1' then
|
|
count <= width;
|
|
prescale <= x"F"; -- sync prescale with rategen
|
|
end if;
|
|
if loadwidth = '1' then
|
|
width <= ibus(16 downto 0);
|
|
end if;
|
|
end if; -- clk
|
|
pwmout <= not countmsb;
|
|
|
|
end process;
|
|
|
|
end Behavioral;
|