MIDI setup

TrackJammer uses two MIDI connections:

Connection	Device	Default port name
Control surface	Launchpad Mini MK3: pad input and output	LPMiniMK3
Sequencer	Circuit Tracks: clock in, notes and CC out	Circuit Tracks

The app looks for both ports when it starts and checks again every 3 seconds, so a device plugged in later is picked up. Names are matched by substring: a port called Circuit Tracks 1 matches Circuit Tracks.

Launchpad programmer mode

When the Launchpad connects, the app switches it to programmer mode, which lets the app light every pad. When the app exits or the Launchpad disconnects, the Launchpad goes back to live mode.

Choose the port names

The app reads the names from three places. Each later one wins:

1. The midi_config.json shipped with the program. Its values are the names in the table above.
2. A midi_config.json in Godot’s user folder (user://). If this file exists, it is used instead of the shipped one, so it must give all four names.
3. Command-line arguments.

Setting	Command-line argument	JSON key
Launchpad input	--control-input <name>	control_surface.input_name
Launchpad output	--control-output <name>	control_surface.output_name
Circuit input	--sequencer-input <name>	sequencer.input_name
Circuit output	--sequencer-output <name>	sequencer.output_name
Turn automatic connection off	--no-auto-connect	(command line only)

The shipped file looks like this:

{
	"control_surface": {
		"input_name": "LPMiniMK3",
		"output_name": "LPMiniMK3"
	},
	"sequencer": {
		"input_name": "Circuit Tracks",
		"output_name": "Circuit Tracks"
	}
}

Note

The user folder is not the data folder. It is Godot’s per-application folder, named after the project (Tracks Jammer MIDI Sequencer), and its location depends on your operating system. On Windows it is normally in your AppData Roaming folder, under Godot/app_userdata.

Connect by hand

If automatic connection is turned off, or the Launchpad and the sequencer were not both found, the connection tab in the app window shows the input and output lists. Pick the ports there. You can select more than one output.

Virtual port and all devices

Where the platform allows it, the app also opens a virtual MIDI output port. A track whose device is set to all devices sends to every open output, including that virtual port. See Track > Params.

Circuit Rhythm

The Circuit Rhythm preset has the same default channels as the Circuit Tracks. The preset in use is named by output_device in data/config/settings.json; when it is empty, the Circuit Tracks preset is used. There is no pad or screen for changing it. To use a Circuit Rhythm, also set the sequencer port names above to its port name.

Clock

The sequencer runs on one clock source at a time. By default the Circuit Tracks is the clock master. To make TrackJammer the master instead, see Global > Clock. Playback problems are covered in Troubleshooting.