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Computer Music: Musc 216
MIDI Commands
There are EIGHT groups (families) of commands which are sent/received
by a MIDI device, usually a synthesizer keyboard, sound module, computer,
or other piece of hardware. In some instances, computer software will
EMULATE a piece of MIDI hardware.
1. Note OFF
2. Note ON
3. Polyphonic key pressure
4. Control change
5. Program change
6. Monophonic key (channel) pressure
7. Pitch bend
8. System exclusive (usually GLOBAL commands affecting the entire
device)
A MIDI command consists of a series of numbers which when received
by a device through a serial cable (or virtual connection made with
software) will cause the device to do something, for example: play a
note, change the sound (program), turn a note off, etc.
Except for the SYSTEM EXCLUSIVE command (which can have any quantity
of individual numbers from as few as 4 to as many as 1000's), all MIDI
commands have either TWO or THREE numbers. For example:
144 60 127 - turn ON note #60 on MIDI channel 1 with a velocity
of 127
144 60 0 - turn OFF note #60 on MIDI channel 1
192 15 - change the program (sound) on MIDI channel 1 to program
#15
193 21 - change the program (sound) on MIDI channel 2 to program
#21
The FIRST number in any MIDI command is called the STATUS and is always
in the range 128 - 255. The number(s) following the STATUS are DATA
and are always in the range 0 - 127. Some MIDI commands have only ONE
DATA number and some have TWO. Here is a list of the various MIDI COMMANDS
along with their respective data requirements (the commands in italics
will not be used in this class):
| STATUS (128 - 255) |
DATA 1 (0 - 127) |
DATA 2 (0 - 127) |
| Note OFF |
Key # |
Off Velocity |
| Note ON |
Key # |
On Velocity |
| Poly Key Pressure |
Key # |
Pressure value |
| Control Change |
Control # |
Control Value |
| Program Change |
Program # |
-- Not Used -- |
Mono Key Pressure
(Channel Pressure) |
Pressure Value (0-127) |
-- Not Used -- |
| Pitch Bend |
Range (LSB) |
Range (MSB) |
| System |
Manufacturer's ID |
Model ID |
The MIDI specification allows for 16 MIDI channels and
MIDI activity can take place on all 16 MIDI channels simultaneously.
MIDI channels are identified by individual MIDI commands through the
the RANGE of their STATUS numbers. For an example, let's look at the
range of numbers in the NOTE ON status command:
| STATUS |
DATA BYTE 1 |
DATA BYTE 2 |
COMMENT |
| 144 |
60 |
127 |
Note ON channel 1 |
| 145 |
60 |
127 |
Note ON channel 2 |
| 146 |
60 |
127 |
Note ON channel 3 |
| 147 |
60 |
127 |
Note ON channel 4 |
| 148 |
60 |
127 |
Note ON channel 5 |
| 149 |
60 |
127 |
Note ON channel 6 |
| 150 |
60 |
127 |
Note ON channel 7 |
| 151 |
60 |
127 |
Note ON channel 8 |
| 152 |
60 |
127 |
Note ON channel 9 |
| 153 |
60 |
127 |
Note ON channel 10 |
| 154 |
60 |
127 |
Note ON channel 11 |
| 155 |
60 |
127 |
Note ON channel 12 |
| 156 |
60 |
127 |
Note ON channel 13 |
| 157 |
60 |
127 |
Note ON channel 14 |
| 158 |
60 |
127 |
Note ON channel 15 |
| 159 |
60 |
127 |
Note ON channel 16 |
The range of possible STATUS number is 128 - 255. Here
is a list of the EIGHT MIDI command STATUS groups along with the range
of numbers for the 16 MIDI channels in each group:
|
COMMAND
MIDI Chans 1-16
|
DATA BYTE 1 |
DATA BYTE 2 |
COMMENT |
| 128-143 |
Key # (0-127) |
Off Velocity (0-127) |
Note OFF |
| 144-159 |
Key # (0-127) |
On Velocity (0-127) |
Note ON |
| 160-175 |
Key # (0-127) |
Pressure (0-127) |
Poly Key Pressure |
| 176-191 |
Control # (0-127) |
Control Value (0-127) |
Control Change |
| 192-207 |
Program # (0-127) |
-- Not Used -- |
Program Change |
| 208-223 |
Pressure Value (0-127) |
-- Not Used -- |
Mono Key Pressure (Channel Pressure) |
| 224-239 |
Range (LSB) |
Range (MSB) |
Pitch Bend |
| 240-255 |
Manufacturer's ID |
Model ID |
System |
An easier way to deal with the complexity of keeping
track of the STATUS number in regards to which MIDI channel it represents
is to use HEXADECIMAL numbers instead of DECIMAL. For example, the
#192 by itself does not intuitively indicate that that is the STATUS
command for changing the program (sound) on MIDI channel 1. However
if this table of HEXADECIMAL values was used for the STATUS numbers,
it becomes immediately intuitive and easy to memorize:
| COMMAND |
DATA BYTE 1 |
DATA BYTE 2 |
COMMENT |
$80-$8F
[128-143] |
Key # (0-127) |
Off Velocity (0-127) |
Note OFF |
$90-$9F
[144-159] |
Key # (0-127) |
On Velocity (0-127) |
Note ON |
| $A0-$AF |
Key # (0-127) |
Pressure (0-127) |
Poly Key Pressure |
$B0-$BF
[176-191] |
Control # (0-127) |
Control Value (0-127) |
Control Change |
$C0-$CF
[192-207] |
Program # (0-127) |
-- Not Used -- |
Program Change |
| $D0-$DF |
Pressure Value (0-127) |
-- Not Used -- |
Mono Key Pressure (Channel Pressure) |
| $E0-$EF |
Range (LSB) |
Range (MSB) |
Pitch Bend |
| $F0-$FF |
Manufacturer's ID |
Model ID |
System |
* NOTE: Due to the hardware limitations of our lab,
items in Italics will not be
implemented in this class.
See: MIDI Resources
See: MIDI
Status BYTES
See: Counting in
Various BASES
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