Siren includes a portable MIDI I/O framework that consists of an abstract I/O port class (MIDIPort), a plug-in that uses the DLLCC interface, and a C-language interface module that talks to the platform-independent PortMIDI library. The higher-level model is that a MIDI voice object holds onto a MIDI device and a channel. The MIDI device object is connected to a MIDI port. For example, the verbose way to create the default MIDI voice would be to say
   MIDIVoice on: (MIDIDevice on: (MIDIPort default openOutput))

The voice object gives us the standard voice behavior (like event mapping and scheduling). The MIDI device allows us to model the device-specific messages supported by some devices. (I used to use micro-tonal extended messages on a few different hardware synths.) The MIDIPort is used for the interface betweeen Siren and external MIDI drivers and devices. It implements both note-oriented (e.g., play: pitch at: aDelay dur: aDur amp: anAmp voice: voice), and data-oriented (e.g., put: data at: delay length: size) behaviors for MIDI I/O.

There is typically only one instance of MIDIPort; the messages new, default, and instance all answer the sole instance. MIDIPorts use observers (dependency) to signal input data--objects wishing to receive input should register themselves as dependents of a port. In the default Siren implementation, the scheduler is all in Smalltalk, and only the simplest MIDI driver is assumed.

MIDI Implementation: The class PortMIDIPort implements the low-level MIDI I/O messages by talking to the PortMidiInterface external class, which is a front-end to C-language glue code that talks to the PortMIDI library. If you set the verbosity to 2 and open a port, it will print your entire device table to the VM's standard output and to the Transcript; for my system, this looks like the following:

Midi Device Table
   0: IAC Driver IAC Bus 1 - in
   1: IAC Driver IAC Bus 2 - in
   2: IAC Driver IAC Bus 3 - in
   3: PC-1600X - in
   4: StudioLogic SL-161 - in
   5: Tascam FW-1804 FW-1804 Control Port - in
   6: IAC Driver IAC Bus 1 - out
   7: IAC Driver IAC Bus 2 - out
   8: IAC Driver IAC Bus 3 - out
   9: Tascam FW-1804 FW-1804 Port 1 - out
   10: EM-100 - out
   11: Tascam FW-1804 FW-1804 Port 3 - out
   12: Tascam FW-1804 FW-1804 Port 4 - out
   13: Tascam FW-1804 FW-1804 Control Port - out

MIDI Tests and Examples

Basic Tests

Edit the methods MIDIPort initialize to suit your setup.

Try to open and close the MIDI port (this also reports to the transcript and dumps a device list to the VM's stdout).
   [MIDIPort testOpenClose]

Open MIDI, play a 1-sec. note.
   [MIDIPort testANote]

Open MIDI, play a fast scale.
   [MIDIPort testAScale]

Open MIDI, play notes based on the mouse position (x --> voice; y --> pitch) until mouse down.
   [MIDIPort testMouseMIDI]
   [MIDIPort allNotesOff]

Close down and clean up.
   [MIDIPort cleanUp]

Using voices
   [MIDIVoice randomExample]
   [MIDIVoice scaleExample]
   [MIDIVoice voiceInspect]

General MIDI Maps and Program Changes

"Demonstrate program change by setting up an organ instrument to play on.
   [MIDIPort testProgramChange]

Down-load a general MIDI patch for a 4-voice organ.
   [MIDIPort setupOrgan. Cluster example1]

Down-load a general MIDI patch for a 16-voice percussion ensemble.
   [MIDIPort setupTunedPercussion. MIDIPort testAScale]

Or try these
   [MIDIPort setAllInstrumentsTo: 'Tenor Sax'. MIDIPort testAScale]
   [MIDIPort setAllInstrumentsTo: 'Music Box'. MIDIPort testAScale]

Reset the GM map (for the first 16 instruments)
   [MIDIPort setupDefaultGeneralMIDI]

MIDI Input

Open MIDI, try to read something--dump it to the transcript.
   [MIDIPort testInput]
   [MIDIPort dumpExample]

Execute this to end the input test
   [MIDIPort testInputStop]

Get the port's pending input.
   [MIDIPort default eventsAvailable]
   [MIDIPort default readAll]
   [MIDIPort default input]
   [MIDIPort default resetInput]

Set up a MIDI dump object as a dependent of the input port. Dump for 5 seconds,
then turn off. The default update: method just dumps the MIDI packet into the transcript.
   [MIDIPort dumpExample]

This example captures notes to an event list for 5 seconds and opens an editor on it.
   [MIDIDump exampleList]

Set up uncached controller reading and dump input to the transcript.
   [MIDIPort testControllerInput]
   [MIDIPort testInputStop]

Set up uncached controller reading--read controllers from lo to hi as an array and print it;
stop on mouse press.
   [MIDIPort testControllerCachingFrom: 48 to: 52]

Real-time Performance Tests

Play ''num'' random pitches spaced ''dur'' msec apart.
This test creates the messages and does the scheduling right here.
   [MIDIPort testRandomPlayLowLevel: 64 dur: 80]

Play a roll of 'num' notes spaced 'dur' msec apart.
This test creates the messages and does the scheduling right here.
   [ObjectMemory compactingGC.
      MIDIPort testRollLowLevel: 20 dur: 80]

   [ObjectMemory compactingGC.
      MIDIPort testRollLowLevel: 200 dur: 40]

Continuous Control Tests

Demonstrate control commands by playing a note and making a crescendo with the volume pedal.
   [MIDIPort testControlContinuous]

Demonstrate pitch-bend by playing two notes and bending them.
   [MIDIPort testBend]

Recording Continuous Controllers

One can also record functions from input controlers, as in the following example, which reads MIDI controller 48 at a rate of 40 Hz for 5 seconds.

   [MIDIPort testControllerRecording]

Utilities

ANO
   [MIDIPort allNotesOff]

Close down and clean up
   [MIDIPort cleanUp]

If things get wedged, do this
   [PortMidiInterface unloadLibraries]

For much more detail, see the class example messages in MIDIPort, or the tests in the PortMIDIPort and PortMidiInterface classes.