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[/] [ppx16/] [trunk/] [rtl/] [vhdl/] [PPX_Port.vhd] - Rev 3
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-- -- PIC16xx compatible microcontroller core -- -- Version : 0146 -- -- Copyright (c) 2001-2002 Daniel Wallner (jesus@opencores.org) -- -- All rights reserved -- -- Redistribution and use in source and synthezised 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 synthesized 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 the author nor the names of other contributors may -- be used to endorse or promote products derived from this software without -- specific prior written permission. -- -- 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 AUTHOR 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. -- -- Please report bugs to the author, but before you do so, please -- make sure that this is not a derivative work and that -- you have the latest version of this file. -- -- The latest version of this file can be found at: -- http://www.opencores.org/cvsweb.shtml/t51/ -- -- Limitations : -- Registers implemented in this entity are INDF, PCL, STATUS, FSR, (PCLATH) -- other registers must be implemented externally including GPR -- -- File history : -- library IEEE; use IEEE.std_logic_1164.all; entity PPX_Port is port( Clk : in std_logic; Reset_n : in std_logic; Port_CS : in std_logic; Rd : in std_logic; Wr : in std_logic; Tris_Rd : in std_logic; Tris_Wr : in std_logic; Data_In : in std_logic_vector(7 downto 0); Data_Out : out std_logic_vector(7 downto 0); IOPort : inout std_logic_vector(7 downto 0) ); end PPX_Port; architecture rtl of PPX_Port is signal Tris : std_logic_vector(7 downto 0); signal Port_Output : std_logic_vector(7 downto 0); signal Port_Input : std_logic_vector(7 downto 0); begin IOPort(0) <= Port_Output(0) when Tris(0) = '0' else 'Z'; IOPort(1) <= Port_Output(1) when Tris(1) = '0' else 'Z'; IOPort(2) <= Port_Output(2) when Tris(2) = '0' else 'Z'; IOPort(3) <= Port_Output(3) when Tris(3) = '0' else 'Z'; IOPort(4) <= Port_Output(4) when Tris(4) = '0' else 'Z'; IOPort(5) <= Port_Output(5) when Tris(5) = '0' else 'Z'; IOPort(6) <= Port_Output(6) when Tris(6) = '0' else 'Z'; IOPort(7) <= Port_Output(7) when Tris(7) = '0' else 'Z'; Data_Out <= Port_Input when Port_CS = '1' and Rd = '1' else "ZZZZZZZZ"; process (Clk) begin if Clk'event and Clk = '1' then Port_Input <= IOPort; -- Synchronise input if Port_CS = '1' and Wr = '1' then Port_Output <= Data_In; Port_Input <= Data_In; end if; end if; end process; Data_Out <= Tris when Tris_Rd = '1' else "ZZZZZZZZ"; process (Reset_n, Clk) begin if Reset_n = '0' then Tris <= "11111111"; elsif Clk'event and Clk = '1' then if Tris_Wr = '1' then Tris <= Data_In; end if; end if; end process; end;
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