Data commit

Task/Musical-scale/XPL0/musical-scale.xpl0

@@ -0,0 +1,21 @@
+\Square waves on the beeper speaker:
+code Sound=39;
+real Period;  int I;
+[Period:= 1190000.0/261.625565;     \middle C
+for I:= 2 to 9 do
+    [Sound(1, 4, fix(Period));      \times 2^(-1/6) else 2^(-1/12)
+    Period:= Period * (if I&3 then 0.890898719 else 0.943874313);
+    ];
+]
+
+\MIDI grand piano (requires 32-bit Windows or Sound Blaster 16):
+code Sound=39;
+int  Note, I;
+[port($331):= $3F;      \set MPU-401 into UART mode
+Note:= 60;              \start at middle C
+for I:= 2 to 9+1 do     \(last note is not played)
+    [port($330):= $90;  port($330):= Note;  port($330):= $7F;
+    Sound(0, 4, 1);     \This "Sound" is off, but convenient 0.22 sec delay
+    Note:= Note + (if I&3 then 2 else 1);
+    ];
+]