-- -----------------------------------------------------------------------------
-- IRDA2RXD - a IrDA 1.0 signal to RS232 TxD decoder --
-- -----------------------------------------------------------------------------
--
-- File : 'irda2rxd.vhd'
-- Author : Lars Larsson
--
-- Date : February 15, 1999
--
-- Description : This converts an IrDA 1.0 RxD_A signal into a RS232 RxD
-- signal. The baud rate is adjusted by the bit time parameter T.
--
-- -----------------------------------------------------------------------------
--
-- Copyright (C) 1999 Lars Larsson, Dept. of Computer Science
-- University of Hamburg
-- Vogt-Koelln-Str. 30
-- D - 22041 Hamburg, Germany
-- larsson@informatik.uni-hamburg.de
-- http://tech-www.informatik.uni-hamburg.de/~larsson
--
-- 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.,
-- 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
--
-- -----------------------------------------------------------------------------
library ieee;
use ieee.std_logic_1164.all;
use ieee.std_logic_arith.all;
entity irda2rxd is
port(
t : in time; -- T_BAUD = 1/(baud rate)
irda_rxda : in std_ulogic; -- IrDA 1.0 RxD_A input (low active)
rs232_rxd : out std_ulogic -- RS232 RxD output
);
end irda2rxd;
architecture simulate of irda2rxd is
signal baud_clk_s : std_ulogic;
signal irda_s : std_ulogic := '0';
begin
irda_p : process ( irda_rxda )
begin
if (irda_rxda'event and irda_rxda='0') then
irda_s <= '0' after 0 ns, '1' after t/4;
end if;
end process;
baud_p : process
begin
wait on irda_s for 1 ns;
baud_clk_s <= '0'; wait for t/2;
baud_clk_s <= '1'; wait for t/2;
end process;
rxd_p : process (baud_clk_s, irda_s)
begin
if (baud_clk_s'event and baud_clk_s='1') then
rs232_rxd <= irda_rxda;
end if;
end process;
end simulate;
-- -----------------------------------------------------------------------------
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