chirp.vhd
85 lines
| 2.9 KiB
| text/x-vhdl
|
VhdlLexer
pellion
|
r445 | ------------------------------------------------------------------------------ | ||
-- This file is a part of the LPP VHDL IP LIBRARY | ||||
-- Copyright (C) 2009 - 2010, Laboratory of Plasmas Physic - CNRS | ||||
-- | ||||
-- 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 3 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA | ||||
------------------------------------------------------------------------------- | ||||
-- Author : Jean-christophe Pellion | ||||
-- Mail : jean-christophe.pellion@lpp.polytechnique.fr | ||||
-- jean-christophe.pellion@easii-ic.com | ||||
---------------------------------------------------------------------------- | ||||
LIBRARY ieee; | ||||
USE ieee.std_logic_1164.ALL; | ||||
USE IEEE.std_logic_arith.ALL; | ||||
USE IEEE.std_logic_signed.ALL; | ||||
USE IEEE.MATH_real.ALL; | ||||
ENTITY chirp IS | ||||
GENERIC ( | ||||
LOW_FREQUENCY_LIMIT : INTEGER := 0; | ||||
HIGH_FREQUENCY_LIMIT : INTEGER := 2000; | ||||
NB_POINT_TO_GEN : INTEGER := 10000; | ||||
AMPLITUDE : INTEGER := 100; | ||||
NB_BITS : INTEGER := 16); | ||||
PORT ( | ||||
clk : IN STD_LOGIC; | ||||
rstn : IN STD_LOGIC; | ||||
run : IN STD_LOGIC; | ||||
data_ack : IN STD_LOGIC; | ||||
data : OUT STD_LOGIC_VECTOR(NB_BITS-1 DOWNTO 0) | ||||
); | ||||
END chirp; | ||||
ARCHITECTURE beh OF chirp IS | ||||
SIGNAL reg : STD_LOGIC_VECTOR(NB_BITS-1 DOWNTO 0); | ||||
SIGNAL n : INTEGER; | ||||
SIGNAL current_time : REAL := REAL(0); | ||||
SIGNAL freq_chirp : REAL := REAL(0); | ||||
BEGIN -- beh | ||||
current_time <= REAL(n) / REAL(NB_POINT_TO_GEN); | ||||
freq_chirp <= REAL(LOW_FREQUENCY_LIMIT) + (REAL(HIGH_FREQUENCY_LIMIT) - REAL(LOW_FREQUENCY_LIMIT))*current_time; | ||||
PROCESS (clk, rstn) | ||||
BEGIN -- PROCESS | ||||
IF rstn = '0' THEN -- asynchronous reset (active low) | ||||
reg <= (OTHERS => '0'); | ||||
n <= 0; | ||||
ELSIF clk'event AND clk = '1' THEN -- rising clock edge | ||||
IF run = '0' THEN | ||||
reg <= (OTHERS => '0'); | ||||
n <= 0; | ||||
ELSE | ||||
IF data_ack = '1' THEN | ||||
IF n < NB_POINT_TO_GEN THEN | ||||
n <= n+1; | ||||
reg <= conv_std_logic_vector(INTEGER(REAL(AMPLITUDE) * SIN(MATH_2_PI*current_time*freq_chirp)),NB_BITS); | ||||
ELSE | ||||
reg <= (OTHERS => '0'); | ||||
END IF; | ||||
END IF; | ||||
END IF; | ||||
END IF; | ||||
END PROCESS; | ||||
data <= reg; | ||||
END beh; | ||||