Display bytewise memory layout

Question

I want to graphically represent the memory layout of an eeprom.
I'd like to have a similar graphic like this one:

I especially need to write on top of an underlying table structure with differnt coloured backgrounds.
Is there a package that allows to do this, is it only possible to do this with tikz, or is there some other easier way?

Answer 1

Here's how to do it in tikz:

\documentclass[tikz, border=20]{standalone}
\begin{document}
    \begin{tikzpicture}
        % Grid
        \draw[step=0.5] (0, 0.99) grid (8, 3);
        \foreach \x in {0, 0.5, ..., 8} {
            \draw (\x, 1) -- (\x, 0);
        }
    % Memory Labels
    \foreach \a/\x in {0/0, 1/1, 2/2, 3/3, 4/4, 5/5, 6/6, 7/7, 8/8, 9/9, A/10, B/11, C/12, D/13, E/14, F/15} {
        \node at ({0.5*(\x+0.5)}, 3.25) {\texttt{\a}};
    }
    \foreach \a/\y in {0x00/0, 0x10/1, 0x20/2, 0x30/3} {
        \node at (-0.5, {3-0.5*(\y+0.5)}) {\texttt{\a}};
    }
    \node at (-0.5, 0.75) {\(\vdots\)};

    \tikzset{block/.style={rounded corners, #1, fill=#1!50, opacity=0.8}}
    \pgfmathsetmacro{\offset}{0.05}
    % Coloured lines
    \draw[block=yellow] (0 + \offset, 2.5 + \offset) rectangle (0.5 - \offset, 3 - \offset);
    \draw[block=red] (0.5 + \offset, 2.5 + \offset) rectangle (6.5 - \offset, 3 - \offset);
    \draw[block=green] (6.5 + \offset, 2.5 + \offset) rectangle (8 - \offset, 3 - \offset);
    \draw[block=green] (0 + \offset, 2 + \offset) rectangle (4.5 - \offset, 2.5 - \offset);
    \draw[block=blue] (4.5 + \offset, 2 + \offset) rectangle (8 - \offset, 2.5 - \offset);
    \draw[block=blue] (0 + \offset, 1.5 + \offset) rectangle (8 - \offset, 2 - \offset);
    \draw[block=blue] (0 + \offset, 1 + \offset) rectangle (1.5 - \offset, 1.5 - \offset);
    \draw[block=purple] (1.5 + \offset, 1 + \offset) rectangle (5.5 - \offset, 1.5 - \offset);

    % Message labels
    \node at (0.25, 2.75) {\(\star\)};
    \node[right] at (0.5, 2.7) {\texttt{Message 1}};
    \node[right] at (6.5, 2.7) {\texttt{M2}};
    \node[right] at (0, 2.2) {\texttt{Message 2}};
    \node[right] at (4.5, 2.2) {\texttt{Message 3}};
    \node[right] at (0, 1.7) {\texttt{Message 3}};
    \node[right] at (0, 1.2) {\texttt{M3}};
    \node[right] at (1.5, 1.2) {\texttt{Message 4}};

    % Config byte label
    \draw[block=yellow] (8.5 + \offset, 2.5 + \offset) rectangle (11.5 - \offset, 3 - \offset);
    \node[below right] at (8.5, 3) {\parbox{2.75cm}{\(\star\) Config Byte: Stores number of messages}};

    % Title
    \node at (4, 4) {EEPROM Memory---256 bytes};
\end{tikzpicture}

\end{document}

This is a very manual way to do it though. If you wanted to do something much bigger than this then you would be best off defining some more nodes.

Answer 2

Another example. More tikz but with a macro for the messages.

\documentclass[border=2mm]{standalone}
\usepackage    {tikz}
\usetikzlibrary{calc}
\ExplSyntaxOn
\NewExpandableDocumentCommand{\makeAlph}{m} % from egreg's answer, https://tex.stackexchange.com/questions/595043/
{ % returns an hex digit
  \int_compare:nTF { 10 <= #1 <= 15 } { \int_to_Alph:n { #1 - 9 } } {#1}
}
\ExplSyntaxOff
\newcommand\mymessage[4] % position, length, color, text
{
  \draw[rounded corners,draw=#3,fill=#3!50,fill opacity=0.75] ($#1+(0.1,0.1)$) rectangle ($#1+(#2-0.1,0.9)$);
  \node[right] at ($#1+(0.075,0.55)$) {\ttfamily\strut#4};
}
\begin{document}
\begin{tikzpicture}[scale=0.5,y=-1cm,line cap=round,line join=round]
% table
\node at (8,-2) {\large\bfseries\sffamily EEPROM Memory - 256 bytes};
\draw (0,6) |- (16,0);
\foreach\i in {0,...,15}
  \draw (\i+1,0) node [above, xshift=-0.25cm] {\ttfamily\makeAlph{\i}} --++ (0,6);
\foreach\i in {0,...,3}
  \draw (0,\i+1) node[left, yshift=0.25cm] {\ttfamily 0x\i0} --++ (16,0);
\node at (0,5) [xshift=-0.6cm, yshift=0.25cm] {$\vdots$};
% messages
\mymessage{( 0,0)}{ 1}{orange} {$\star$};
\mymessage{( 1,0)}{12}{red}    {Message 1};
\mymessage{(13,0)}{ 3}{green}  {M2};
\mymessage{( 0,1)}{ 9}{green}  {Message 2};
\mymessage{( 9,1)}{ 7}{blue}   {Message 3};
\mymessage{( 0,2)}{16}{blue}   {Message 3};
\mymessage{( 0,3)}{ 3}{blue}   {M3};
\mymessage{( 3,3)}{ 9}{magenta}{Message 4};
\mymessage{(17,0)}{ 5}{orange} {\rmfamily$\star$  Config Byte:};
\mymessage{(17,1)}{ 5}{white}  {\rmfamily Stores number};
\mymessage{(17,2)}{ 5}{white}  {\rmfamily of messages};
\end{tikzpicture}
\end{document}

Answer 3

OK, for what it's worth, I came with another solution, very close to Juan's one, but without any expl3 coding. Here it is:

\documentclass[tikz,border=3.14mm]{standalone}
\usetikzlibrary{positioning}
\newcommand{\blok}[4]{%
        \def\sft{2pt} % shift from border of cells to coloured rectangles
        \draw[rounded corners=2pt,opacity=0.8,#1,fill=#1!50,thick] ([shift={(\sft,-\sft)}]#2.north west) rectangle ([shift={(-\sft,\sft)}]#3.south east);
        \node[right] at ([xshift=-0.44*\s cm]#2.center) {#4};}
\begin{document}
    \begin{tikzpicture}[font=\ttfamily]
    \def\s{0.5} % size of cells
    \foreach \l [count=\k from 0] in {a,...,e}
        \foreach \i in {0,...,15}  
            \node[draw,minimum size=\s cm] (\l\i) at (\i*\s,-\k*\s){};
    \foreach \c [count=\i from 0] in {0,...,9,A,B,...,F} \node[above] at (a\i.north) {\c};
    \foreach \l [count=\i from 0] in {a,...,d} \node[left] (\l) at (\l0.west) {0x\i 0};
    \node [below= -5pt of d] {\vdots};

    \blok{orange}{a0}{a0}{*}
    \blok{red}{a1}{a12}{Message 1}
    \blok{olive}{a13}{a15}{M2}

    \blok{olive}{b0}{b7}{Message 2}
    \blok{teal}{b8}{b15}{Message 3}

    \blok{teal}{c0}{c15}{Message 3}
    \blok{teal}{d0}{d2}{M3}
    \blok{purple}{d3}{d9}{Message 4}

    \node[right,inner ysep=0 pt,minimum size=\s cm](star1) at (16*\s,0){};
    \node[minimum height=\s cm,right= 2cm  of star1](star2){};
    \blok{orange}{star1}{star2}{* Config Byte}
    \path (star1) -- (star2) node[midway,below=6pt,font=\sffamily,text width=2.5cm]{Stores number of messages};
\end{tikzpicture}

\end{document}