URL
https://opencores.org/ocsvn/simple_fm_receiver/simple_fm_receiver/trunk
Subversion Repositories simple_fm_receiver
[/] [simple_fm_receiver/] [trunk/] [source/] [nco.vhdl] - Rev 23
Go to most recent revision | Compare with Previous | Blame | View Log
-- $Id: nco.vhdl,v 1.4 2008-06-26 06:16:04 arif_endro Exp $ ------------------------------------------------------------------------------- -- Title : NCO (Numerical Controlled Oscillator) -- Project : FM Receiver ------------------------------------------------------------------------------- -- File : nco.vhdl -- Author : "Arif E. Nugroho" <arif_endro@yahoo.com> -- Created : 2004/10/27 -- Last update : -- Simulators : -- Synthesizers: -- Target : ------------------------------------------------------------------------------- -- Description : Works like VCO in analog PLL ------------------------------------------------------------------------------- -- Copyright (C) 2004 Arif E. Nugroho -- This VHDL design file is an open design; you can redistribute it and/or -- modify it and/or implement it after contacting the author ------------------------------------------------------------------------------- ------------------------------------------------------------------------------- -- -- 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 SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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. -- ------------------------------------------------------------------------------- library IEEE; use IEEE.STD_LOGIC_1164.all; entity nco is port ( clock : in bit; clear : in bit; input_nco : in bit_vector (17 downto 0); offset : in bit_vector (17 downto 0); output_nco : out bit_vector (07 downto 0) ); end nco; architecture structural of nco is component addacc port ( clock : in bit; acc : in bit_vector (17 downto 0); result : out bit_vector (17 downto 0); offset : in bit_vector (17 downto 0) ); end component; component rom port ( address : in bit_vector (09 downto 0); data : out bit_vector (07 downto 0) ); end component; signal adder_output : bit_vector (17 downto 0); signal address_in : bit_vector (09 downto 0); signal output_rom : bit_vector (07 downto 0); begin myaddacc : addacc port map ( clock => clock, acc => input_nco, result (17 downto 0) => adder_output, offset => offset ); myrom : rom port map ( address (09 downto 0) => address_in, data (07 downto 0) => output_rom ); address_in (09) <= (adder_output(17)); address_in (08) <= (adder_output(16)); address_in (07) <= (adder_output(15)); address_in (06) <= (adder_output(14)); address_in (05) <= (adder_output(13)); address_in (04) <= (adder_output(12)); address_in (03) <= (adder_output(11)); address_in (02) <= (adder_output(10)); address_in (01) <= (adder_output(09)); address_in (00) <= (adder_output(08)); -- process (clock, clear) process (clock) begin -- 20080625 -- fixme -- how to enable clear signal in here... :( -- if (clear = '1') then if ((clock = '1') and clock'event) then -- output_nco <= (others => '0'); -- elsif (((clock = '1') and (not(clear) = '1')) and clock'event) then output_nco (07) <= (output_rom(07)); output_nco (06) <= (output_rom(06)); output_nco (05) <= (output_rom(05)); output_nco (04) <= (output_rom(04)); output_nco (03) <= (output_rom(03)); output_nco (02) <= (output_rom(02)); output_nco (01) <= (output_rom(01)); output_nco (00) <= (output_rom(00)); end if; end process; end structural;
Go to most recent revision | Compare with Previous | Blame | View Log