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-- Company: 
-- Engineer: 
-- 
-- Create Date:    10:35:29 07/04/2006 
-- Design Name: 
-- Module Name:    l3pcmcia - Behavioral 
-- Project Name: 
-- Target Devices: 
-- Tool versions: 
-- Description: 
--
-- Dependencies: 
--
-- Revision: 
-- Revision 0.01 - File Created
-- Additional Comments: 
--
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library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
use IEEE.STD_LOGIC_ARITH.ALL;
use IEEE.STD_LOGIC_UNSIGNED.ALL;

---- Uncomment the following library declaration if instantiating
---- any Xilinx primitives in this code.
--library UNISIM;
--use UNISIM.VComponents.all;

entity Balloon_pcmcia is
	port (
			data_bus_in : in std_logic_vector(15 downto 0);
			data_bus_out : out std_logic_vector(15 downto 0);
			address_bus : in std_logic_vector(10 downto 0);
			bus_rdnwr : in std_logic;
			nreset : in std_logic;
			want_bus : out std_logic;
			card_data : inout std_logic_vector(15 downto 0);
			card_address : out std_logic_vector(10 downto 0);
			park_interface : in std_logic;
			enable_pcmcia : in std_logic;
			address_enable : in std_logic;
			cpu_npoe : in std_logic;
			cpu_npce1 : in std_logic;
			cpu_npce2 : in std_logic;
			cpu_npior : in std_logic;
			cpu_npiow : in std_logic;
			cpu_npreg : in std_logic;
			cpu_npwe : in std_logic;
			cpu_npsktsel : in std_logic;
			cpu_niois16 : out std_logic;
			cpu_npwait : out std_logic;
			nstschng_out : out std_logic;
			nrdy_out : out std_logic;
			data_enable_out : out std_logic; --indicates when PCMCIA is driving the databus
			card_reset_in : in std_logic; -- source of card reset
			card_npoe : out std_logic;
			card_npce1 : out std_logic; --lower byte lane enable
			card_npce2 : out std_logic; --upper byte lane enable
			card_npior : out std_logic;
			card_npiow : out std_logic;
			card_npreg : out std_logic; --effectively a11
			card_npwe : out std_logic;  --card write enable
			card_niois16 : in std_logic; --card is 16 bits
			card_npwait : in std_logic; --wait from card
			card_reset : out std_logic; --reset out to card
			card_nstschng : in std_logic;
			card_nrdy : in std_logic
	);
			
end Balloon_pcmcia;

architecture Behavioral of Balloon_pcmcia is
--PCMCIA
	signal data_out_enable : std_logic;
	signal data_in_enable : std_logic;
	signal pcmcia_select : std_logic;

begin
--PCMCIA/CF Card Interface
-- Initially a single card solution based on the CF socket.
-- In principle this can also use the backplane.

cpu_niois16	 <= card_niois16  when enable_pcmcia='1' else '1';
cpu_npwait	 <= card_npwait   when enable_pcmcia='1' else '1';
nstschng_out <= card_nstschng when enable_pcmcia='1' else '1';
nrdy_out	    <= card_nrdy     when enable_pcmcia='1' else '1';
card_npoe     <= cpu_npoe    when enable_pcmcia='1' else 'Z';
card_npce1    <= cpu_npce1   when enable_pcmcia='1' else 'Z';
card_npce2    <= cpu_npce2   when enable_pcmcia='1' else 'Z';
card_npior    <= cpu_npior   when enable_pcmcia='1' else 'Z';
card_npiow    <= cpu_npiow   when enable_pcmcia='1' else 'Z';
card_npreg    <= cpu_npreg   when enable_pcmcia='1' else 'Z';

card_npwe <= cpu_npwe  when (enable_pcmcia='1' and address_enable='1') else '1';
card_reset <= '1' when ( ((nreset = '0') or (card_reset_in = '1')) and (park_interface = '0')) else '0';

--Bus Buffer control
pcmcia_select <= '1' when ((cpu_npce1 = '0' or cpu_npce2 = '0') and enable_pcmcia='1') else '0';
data_out_enable <=  '1' when (pcmcia_select = '1' and cpu_npsktsel = '0' and (cpu_npoe = '0' or cpu_npior='0') ) else '0';
data_in_enable <= '1' when (pcmcia_select = '1' and cpu_npsktsel = '0' and (cpu_npwe = '0' or cpu_npiow='0')) else '0';

card_address <= address_bus when enable_pcmcia='1' and address_enable='1' else "ZZZZZZZZZZZ";

data_bus_out  <= card_data when (data_out_enable = '1') else "ZZZZZZZZZZZZZZZZ";
card_data <= data_bus_in when  (data_in_enable = '1')  else "ZZZZZZZZZZZZZZZZ";
want_bus <= data_out_enable;

end Behavioral;