Let's play a tune now!
It's easy, just a matter of using a ROM to hold the notes.

// use a counter to go through a ROM containing the notes of a little tune that we want to play reg [30:0] tone; always @(posedge clk) tone <= tone+1; wire [7:0] fullnote; music_ROM ROM(.clk(clk), .address(tone[29:22]), .note(fullnote));

We also want that

• the tune pauses after the ROM ends
• the "fullnote" of value 0 is a quiet note.

so we change the last line of the previous design from

always @(posedge clk) if(counter_note==0 && counter_octave==0) speaker <= ~speaker;

into

always @(posedge clk) if(counter_note==0 && counter_octave==0 && tone[30]==0 && fullnote!=0) speaker <= ~speaker;

The rest of the design stays the same.
The complete source is available here. Can you recognize the tune?

That's it folks. Hope it was fun.

Links

• Reverse-engineering a tiny 1980s chip that plays Christmas tunes