no way to compare when less than two revisions

Differences

This shows you the differences between two versions of the page.

@@ Line 1: / Line 1: @@
+====== C64 MIDI Data ======
+A Midi keyboard will output Status bytes and data bytes (if any).
+Status bytes have bit 7 set, while all data bytes have bit 7 cleared.
+<code>
+Status Byte: 80-EF  (Midi & Channel messages)
+Status Byte: F0-F7  (System Common Messages)
+Status Byte: F8-FF  (System Realtime Messages)
+Data Byte:   00-7F  (note, value of pitch bend, value of volume slider, etc..)
+</code>
+Status Bytes between 80-EF controls Midi message and channel number.
+Midi messages uses the high nybble of the Status Byte.
+There are 16 midi channels and these can be read from the low nybble of the Status byte.
+For instance, Midi channel 16 would be hexmal 'F' and Midi Channel 1 would be heximal '0'.
+If we add the status byte for Pitch wheel to these two examples you will get 'EF' and 'E0'
+I will use X as midi channel when describing each Midi message:
+=====$8x NOTE OFF =====
+This is the note off message and it is followed by 2 data bytes.
+  data 1: Note number (0-127)
+  data 2: Velocity (0-127)
+The velocity inidcates how quickly the note should be released.
+Note that on some midi keyboards the Status byte $9x will provide the Note Off message.
+=====$9x NOTE ON =====
+This is the note on message and it is followed by 2 data bytes.
+<code>
+  data 1: Note Number (0-127)
+  data 2: Velocity (0-127)     (0 = note off)
+</code>
+The velocity indicates how hard you press the note on the keyboard.
+If the Velocity is zero, the note should be treated as a Note Off message.
+=====$Ax AFTERTOUCH =====
+This is the aftertouch message and it is followed by 2 data bytes.
+<code>
+  data 1: Note Number (0-127)
+  data 2: Pressure amount (0-127)     (0 = note off)
+</code>
+Some keyboards allows you to add extra pressure on the keys you already have pressed down.
+The pressure amount indicates how hard you press the note when using this.
+=====$Bx CONTROL CHANGE =====
+This is the control change message and it is followed by 2 data bytes.
+<code>
+  data 1: Controller number (0-127)
+  data 2: Value (0-127)
+</code>
+Controller number is usally 1 (modulation wheel) but can also be set to 7 (volume wheel), infact there's 127
+different controler numbers.
+Value is just what it says 0-127.
+=====$Cx PROGRAM CHANGE =====
+This is the program change message and it is followed by 1 data byte.
+<code>
+  data 1: program number (0-127)
+</code>
+=====$Dx CHANNEL PRESSURE =====
+This is the channel pressure message and it is followed by 1 data byte.
+<code>
+  data 1: channel pressure number (0-127, where 127 is the the most pressure).
+</code>
+While notes are playing, pressure can be applied to all of them.
+=====$Ex PITCH WHEEL =====
+This is the pitch wheel message and it is followed by 2 data bytes.
+<code>
+  data 1: bits 0-6 of the 14 bit value (0-127)
+  data 2: bits 7-13 of the 14 bit value (0-127)
+</code>
+The two data bytes should be combined together to form a 14-bit value.
+The value can be used to decrease or increase the pitch.