vhdl string to font 5x7

Question

I am quite new to VHDL and as my first project I created a 20x7 LED display with rotating text. Right now all the STD_LOGIC_VECTORs which printed on the display are set manually.

I was wondering if there is a possibility to get STD_LOGIC_VECTOR representation of rows from a string (or char?). I found usable font, but I don't know where to start...

Answer 1

to implement something like what you asked for in the later comments, you first need a translation function char2int for the addressing of your array. example:

    function char2int (chr: character) return integer is
        variable i: integer;
    begin
        case chr is
        when 'H' => i:=0;
        when 'A' => i:=1;
        when 'L' => i:=2;
        when 'O' => i:=3;
        when others => i:=4;
        end case;

        return i;
    end char2int;

then the main function is as you suggested in your C-example:

    function string_to_bitfile(constant txt_str: string) return text_type is
        variable txt: text_type;
    begin
        for i in 0 to (txt_str'length-1) loop
            for j in 0 to 5 loop
                txt(6*i+j):=font(char2int(txt_str(i)),j);
            end loop;
        end loop;

        return txt;
    end string_to_bitfile;