digraph solution_diagram {
    rankdir=TB;
    nodesep=0.8;
    splines=ortho

    node [
        fontname="JetBrainsMono",
        style="rounded,filled",
        fillcolor="white",
    ];
    edge [
        fontname="JetBrainsMono",
    ];

    // NOTE: for some reason subgraph names have to start with `cluster`
    // otherwise the subgraph is not treated as a box

    subgraph clustermain {
        label="";
        color=none;

        start [
            shape=circle,
            label="",
            style="filled",
            color=black,
            fillcolor=black,
            width=0.3,
            rank=0,
        ];
        init_adc [
            shape=box,
            label="initialise ADC",
        ];
        read_adc [
            shape=box,
            label="read ADC value",
        ];
        dec_t0 [
            shape=diamond,
            label="if T0",
            style="",
        ];
    }

    subgraph clustergreen {
        label="";
        style=filled;
        color="#80D070";

        green [
            shape=box,
            label="set green\nlcd backlight",
        ];
        seg7 [
            shape=box,
            label="output adc value\nto 7seg display",
        ];
        ledbar [
            shape=box,
            label="calculate and\ndisplay led bar",
        ];
    }

    subgraph not_green {
        label="";

        subgraph diff {
            label="";

            read_dip [
                shape=box,
                label="read DIPSW[7..0]",
            ];
            diff [
                shape=box,
                label="DIPSW[7..0]\n- adc value",
            ];
            dec_diff1 [
                shape=diamond,
                label="diff >= 0?",
                style="",
            ];
        }

        subgraph clusterblue {
            label="";
            style=filled;
            color="#7080D0";

            blue [
                shape=box,
                label="set blue\nlcd backlight",
            ];
            dec_diff2 [
                shape=diamond,
                label="diff range",
                style="",
            ];
            disp2 [
                shape=box,
                label="display '2 Bit'\non lcd",
            ];
            disp4 [
                shape=box,
                label="display '4 Bit'\non lcd",
            ];
            disp8 [
                shape=box,
                label="display '8 Bit'\non lcd",
            ];
        }

        subgraph clusterred {
            label="";
            style=filled;
            color="#F07070";

            red [
                shape=box,
                label="set red\nlcd backlight",
            ];
            count0 [
                shape=box,
                label="count zeroes\nin difference\n(binary value)",
            ];
            disp0 [
                shape=box,
                label="display number\nof zeroes on lcd",
            ];
        }
    }

    joint [
        shape=diamond,
        style="",
        label="",
        width=0.4,
        height=0.4,
    ];

    start -> init_adc;
    init_adc -> read_adc;
    read_adc -> dec_t0;

    dec_t0 -> green [xlabel="T0 = 1"];
    green -> seg7;
    seg7 -> ledbar;
    // ledbar -> read_adc;

    dec_t0 -> read_dip [xlabel="T0 = 0"];
    read_dip -> diff;
    diff -> dec_diff1
    dec_diff1 -> blue [xlabel="diff >= 0"];
    blue -> dec_diff2;

    dec_diff2 -> disp2 [xlabel="diff < 4"];
    dec_diff2 -> disp4 [xlabel="diff < 16"];
    dec_diff2 -> disp8 [xlabel="diff >= 16"];

    // disp2 -> read_adc;
    // disp4 -> read_adc;
    // disp8 -> read_adc;

    dec_diff1 -> red [xlabel="diff < 0"];
    red -> count0;
    count0 -> disp0;
    // disp0 -> read_adc;

    ledbar -> joint;
    disp2 -> joint;
    disp4 -> joint;
    disp8 -> joint;
    disp0 -> joint;
    joint -> read_adc;
}