Subversion Repositories single-14-segment-display-driver-w-decoder

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-- Entity: ascii_decoder

-- Date:2017-01-07  

-- Author: GL     

--

-- Description: 

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--! @file

--! @brief ASCII decoding table with I/O control logic

library ieee;

use ieee.std_logic_1164.all;

use ieee.numeric_std.all;

entity ascii_decoder is

        port  (

        clk     : in    std_logic;                                      --! input clock, xx MHz.

        reset   : in    std_logic;

        --! ascii_in(7) represents the DP state so it is not decoded. 

        --! Symbol codes from 0x00 to 0x7F are without DP lit. Symbol codes from 0x80 to 0xFF have DP lit.

        ascii_in: in    std_logic_vector(7 downto 0);                   --! input ascii code to be displayed

        disp_data_q : out std_logic_vector(14 downto 0)                 --! decoded ascii code output with symbol bit map

        );

end ascii_decoder;

architecture arch of ascii_decoder is

    --! Q represents the symbol's bit mapping overlay over the 14-segment display.

    signal Q : std_logic_vector(13 downto 0);

begin

--! @brief Decoding table handling all symbols except the DP

rom_decoding_table: entity work.decoder_table_dist_rom

port map(

    Address => ascii_in(6 downto 0),

    Q       => Q

);

--! Inversion of ascii_in(7) is needed as '0' is display segment active level

disp_data_q <= (not ascii_in(7)) & Q;

end arch;