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-- Entity: display_driver_w_decoder
-- Date:2017-01-06  
-- Author: GL     
--
-- Description: Top module for display driver with decoder
--! @file
--! @brief Display Driver With Decoder Top Level Module
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library ieee;
use ieee.std_logic_1164.all;
use ieee.numeric_std.all;

--! @brief Top entity of the display driver.
--! @details Top entity of the decoder architecture. Module description also goes here.
entity display_driver_w_decoder is
	port  (
        clk     : in    std_logic;                                      --! input clock, xx MHz.
        reset   : in    std_logic;                                      --! active high

        ascii_in: in    std_logic_vector(7 downto 0);                   --! input ASCII code to display
        wr_en   : in    std_logic;                                      --! active high write enable to store the ASCII code in a register
        
        --! Typically the data fed to display (single or multiple) is provided for single display at a time.
        --! If multiple displays are required scan signal must be additionally provided (according typical dynamic display indication).
        --! 
        --! \section disp_data_bit_mapping Display Segment Bit Mapping
        --! |Bit Number     |   14|   13|   12|   11|   10|    9|    8|    7|    6|    5|    4|    3|    2|    1|0    |
        --! |:--------:     |:---:|:---:|:---:|:---:|:---:|:---:|:---:|:---:|:---:|:---:|:---:|:---:|:---:|:---:|:---:|
        --! |Display Segment|   dp|    m|    l|    k|    j|    i|    h|   g2|   g1|    f|    e|    d|    c|    b|a    |
        --! Note that there is no standard way to name the segments. 
        --! Current data bits correspondt to display segments according this picture: @image html https://www.maximintegrated.com/en/images/appnotes/3211/3211Fig02.gif
        disp_data_q : out std_logic_vector(14 downto 0)                  
	);
end display_driver_w_decoder;

--! @brief Architecture definition of the display_driver_w_decoder
--! @details Architecture describes the structure of the module together with doxygen description for doumentation generatior
architecture display_driver_w_decoder_arch of display_driver_w_decoder is

    signal ascii_reg: std_logic_vector(7 downto 0);
    
    attribute syn_noprune: boolean;
    attribute syn_noprune of ascii_reg: signal is true;
begin

    --! \mainpage 14-segment Display Driver Info
    --!
    --! \section intro_sec Introduction
    --!
    --! The main purpose of this module is to be fed with ASCI symbol codes and it will output word lighting up the exact segments 
    --! on the 14-segment display to visualize the ASCII character. Current implementation uses input register to store the input code. 
    --!
    --! ASCII symbols are coded in Byte having values from 0x00 to 0x7F. This range covers all the symbols in the decoding table.
    --! The range is doubled because the symbols may be lit with DP on or off. More information may be found in MAX6955 datasheet.
    --! Follows small revised quote of the most descriptive part related to decoding. Not applicable words are removed.
    --!
    --! ... includes 104-character ASCII font maps for 14-segment... . The characters follow the standard ASCII font, with the
    --! addition of the following common symbols: GBP, EUR, Yen, degree, micro, plus/minus, arrow up, and arrow down. 
    --! Seven bits represent the 104-character font map; an 8th bit is used to select whether the decimal point (DP) is lit.
    --! source: https://datasheets.maximintegrated.com/en/ds/MAX6955.pdf
    --!
    --! \section port_disp_data Display Data Out
    --! 
    --! \subsection disp_data_bit_mapping Display Segment Bit Mapping
    --! |Bit Number     |   14|   13|   12|   11|   10|    9|    8|    7|    6|    5|    4|    3|    2|    1|0    |
    --! |:--------:     |:---:|:---:|:---:|:---:|:---:|:---:|:---:|:---:|:---:|:---:|:---:|:---:|:---:|:---:|:---:|
    --! |Display Segment|   dp|    m|    l|    k|    j|    i|    h|   g2|   g1|    f|    e|    d|    c|    b|a    |
    --! Note that there is no standard way to name the segments. 
    --! Current data bits correspondt to display segments according this picture: @image html https://www.maximintegrated.com/en/images/appnotes/3211/3211Fig02.gif

    ascii_decoder_module:entity work.ascii_decoder
    port map(
        clk         => clk,
        reset       => reset,
        ascii_in    => ascii_in,
        disp_data_q => disp_data_q
    );
    
end display_driver_w_decoder_arch;