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lustrec-tests / vhdl_json / vhdl_files / 2-exportOK / cnes_guidelines / rule / data / STD_05400_bad.vhd @ 2051e520

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1 2051e520 Arnaud Dieumegard
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-- Company   : CNES
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-- Author    : Mickael Carl (CNES)
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-- Copyright : Copyright (c) CNES. 
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-- Licensing : GNU GPLv3
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-- Version         : V1
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-- Version history : 
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--    V1 : 2015-04-10 : Mickael Carl (CNES): Creation
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-- File name          : STD_05400_bad.vhd
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-- File Creation date : 2015-04-10
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-- Project name       : VHDL Handbook CNES Edition 
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-- Softwares             :  Microsoft Windows (Windows 7) - Editor (Eclipse + VEditor)
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-- Description : Handbook example: Unsuitability of internal tristate: bad example
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--
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-- Limitations : This file is an example of the VHDL handbook made by CNES. It is a stub aimed at
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--               demonstrating good practices in VHDL and as such, its design is minimalistic.
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--               It is provided as is, without any warranty.
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--               This example is compliant with the Handbook version 1.
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--
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-- Naming conventions: 
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--
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-- i_Port: Input entity port
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-- o_Port: Output entity port
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-- b_Port: Bidirectional entity port
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-- g_My_Generic: Generic entity port
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--
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-- c_My_Constant: Constant definition 
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-- t_My_Type: Custom type definition
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--
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-- My_Signal_n: Active low signal
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-- v_My_Variable: Variable
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-- sm_My_Signal: FSM signal
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-- pkg_Param: Element Param coming from a package
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--
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-- My_Signal_re: Rising edge detection of My_Signal
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-- My_Signal_fe: Falling edge detection of My_Signal
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-- My_Signal_rX: X times registered My_Signal signal
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--
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-- P_Process_Name: Process
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--
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library IEEE;
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use IEEE.std_logic_1164.all;
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use IEEE.numeric_std.all;
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--CODE
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entity STD_05400_bad is
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   port  (
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      i_A   : in std_logic_vector(3 downto 0); -- Input data of tristate block
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      i_OE  : in std_logic_vector(3 downto 0); -- Enable vector of tristate buffers
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      o_B   : out std_logic                    -- Single module output
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   );
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end STD_05400_bad;
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architecture Behavioral of STD_05400_bad is
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begin
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   -- Assign output with Z or an input value depending on enable signals
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   o_B     <= i_A(3) when (i_OE(3)='1') else 'Z';
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   o_B     <= i_A(2) when (i_OE(2)='1') else 'Z';
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   o_B     <= i_A(1) when (i_OE(1)='1') else 'Z';
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   o_B     <= i_A(0) when (i_OE(0)='1') else 'Z';
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end Behavioral;
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--CODE