I've also introduced a "rests", which will help.

Making an Excel spreadsheet, with lots of use of Concatenate to generate copy and pastable "equ" statements for my assembler has improved things no end... And should make any music I make with it much more portable down the line, so thanks for that tip.

I'll post source code, etc, when I've reached a v1 that I'm happy with.

Ehh, I wish I had Shiru's advice back in the day when I started to make my own engines. Could never wrap my head around it back in the day. Just like I couldn't figure out 16-bit dividers, lol. Speaking of which, I'd say try to figure those out next. Aside from having a greater note range, it actually makes things simpler

Of course, if you have any questions, ask away. More than happy to help.

I have now equ'd my pitch values in my assembler, which at least means I can do that bit slightly quicker now - I can't believe I didn't think of that!

You don't really need to hand tune pitch values, just use any script engine to calculate them out. JS, Python, etc.

Then, if you go with composing by typing in the pitch values, you don't have to have a spreadsheet. Just make aliases, like C_2=100 (or C_2 equ 100 in some assemblers). Now you can just use note names in your db's.

Then, to save time, you can just generate both pitch values and aliases with the same script, and save a ton of time. You can do this with https://js.do/, for example. Just go there, copy/paste code below, click Run.

<script>

    //standart note table for a high octave

    NoteFreqTable=new Array( 2093.0,2217.4,2349.2,2489.0,2637.0,2793.8,2960.0,3136.0,3322.4,3520.0,3729.2,3951.0 );

    NoteNameTable=new Array("C_","Cs","D_","Ds","E_","F_","Fs","G_","Gs","A_","As","B_");
    
    //generate note to period table

    cpuClock=3500000.0;
    cpuToneLoop=200.0;    //cycles per engine loop
    div=32.0;

    for(octave=0;octave<8;++octave)
    {
        for(note=0;note<12;++note)
        {
            period=Math.floor((cpuClock/(cpuToneLoop/2.0))/(NoteFreqTable[note]/div));

            document.write(NoteNameTable[note]+octave+" equ "+period+"<br>");
        }

        div=div/2;
    }

</script>

I know I've been re-inventing-the-wheel here, but I'm still quite proud of doing it from scratch.

It is a monophonic, square-wave monophonic thing - but the duty-cycle varies back and forth as it plays each note from '0-100%' quite pleasingly I think.

It's based on 8-bit 'pitch' values, and I've spent *way* too long hand-tuning it, and then working out values to get a 'lengths' for each of the different pitches of notes that are consistent.

It plays reliably just under 2 octaves (From C#).  I think ultimately I'll make a look up table of pitch values, and length multipliers so it's a bit easier to compose for without an excel spreadsheet to hand!