Programmer’s Reference

1 Introduction

This manual describes Launch Control XL’s MIDI communication format. This is all the proprietary information you need to be able to write patches and applications that are customised for Launch Control XL.

It is assumed that you already have a basic knowledge of MIDI, and some appropriate software for writing interactive MIDI applications (for example, Max for Live, Max/MSP, or Pure Data).

Numbers in this manual are given in both hexadecimal and decimal. To avoid any ambiguity, hexadecimal numbers are always followed by a lower-case h.

2 Launch Control XL MIDI Overview

Launch Control XL is a class-compliant USB device that boasts 24 pots, 8 faders and 24 programmable buttons. The 16 ‘channel’ buttons each contain a bi-coloured LED with a red element and a green element; the light from these elements can be mixed to form amber. The four directional buttons each contain a single red LED. The ‘Device’, ‘Mute’, ‘Solo’ and ‘Record Arm’ buttons each contain a single yellow LED. Launch Control XL has 16 templates: 8 user templates, which can be modified, and 8 factory templates, which cannot. User templates occupy slots 00h-

07h (0-7), whereas factory templates occupy slots 08-0Fh (8-15). Use the Launch Control XL Editor

(available on the Novation website) to modify your 8 user templates.

Launch Control XL has a single MIDI port named ‘Launch Control XL n’, where n is the device ID of your unit (not shown for device ID 1). The button LEDs for any template can be controlled via

System Exclusive messages. Alternatively, button LEDs for the currently selected template can by controlled via MIDI note-on, note-off, and control change (CC) messages, as per the original

Launchpad protocol.

Launch Control XL uses a System Exclusive protocol to update the state of any button on any template, regardless of the currently selected template. In order to maintain compatibility with

Launchpad and Launchpad S, Launch Control XL also adheres to the traditional Launchpad LED lighting protocol via note-on, note-off and CC messages. However, such messages will only be acted upon if the currently selected template contains a button/pot whose note/CC value and

MIDI channel match those of the incoming message. Users are therefore advised to adopt the new

System Exclusive protocol.

In addition, Launch Control XL also supports the original Launchpad double-buffering, flashing and set-/reset-all LED messages, where the MIDI channel of the message defines the template for which the message is intended. These messages can therefore be sent at any time, regardless of which template is currently selected.

The state of each LED is stored when the template is changed and will be recalled when the template is reselected. All LEDs can be updated in the background via Sysex.

Launch Control XL Programmer’s Reference 2

3 Computer-to-Device Messages

LEDs on the Launch Control XL can be set via two different protocols: (1) the traditional

Launchpad MIDI protocol, which requires the currently selected template to contain a button whose note/CC and MIDI channel correspond to the incoming message; and (2) the Launch

Control XL System Exclusive protocol, which will update the required button regardless of its note/CC value or MIDI channel.

In both protocols, a single byte is used to set the intensities of both the red and green LEDs. This byte also includes the Copy and Clear flags. The byte is structured as follows (those unfamiliar with binary notation can read on for the formula):

Bit Name

6

5..4 Green

3

2

Clear

Copy

1..0 Red

Meaning

Must be 0

Green LED brightness

If 1: clear the other buffer’s copy of this LED

If 1: write this LED data to both buffers

Note: this behaviour overrides the Clear behaviour when both bits are set

Red LED brightness

The Copy and Clear bits allow manipulation of the Launch Control XL’s double-buffering feature.

See the ‘Control double-buffering’ message and the Appendix for details about how this can be used.

Each LED can therefore be set to one of four values:

Brightness

0

1

2

3

Meaning

Off

Low brightness

Medium brightness

Full brightness

If the double-buffering features are not in use, it is good practice to keep the Copy and Clear bits set when turning LEDs on or off. This makes it possible to use the same routines in flashing mode without re-working them. A formula for calculating velocity values is:

Hex version

Decimal version Velocity = (16 x Green)

where

Velocity = (10h x Green)

+ Red

+ Flags

+ Red

+ Flags

Flags = 12 (OCh in hex) for normal use;

8 to make the LED flash, if configured;

0 if using double-buffering.

Launch Control XL Programmer’s Reference 3

The following tables of pre-calculated velocity values for normal use may also be helpful:

Hex

0Ch

0Dh

0Fh

1Dh

3Fh

3Eh

Decimal

12

13

15

29

63

62

Colour

Off

Red

Red

Amber

Amber

Yellow

1Ch 28

3Ch 60

Values for flashing LEDs are:

Green

Green

Hex Decimal Colour

0Bh 11 Red

3Bh 59

3Ah 58

38h 56

Amber

Yellow

Green

Brightness

Off

Low

Full

Low

Full

Full

Low

Full

Brightness

Full

Full

Full

Full

Launchpad Protocol

Note On — Set button LEDs

Hex version

Dec version

9nh, Note, Velocity

144+n, Note, Velocity

A note-on message changes the state of all buttons in the currently selected template whose note/CC value matches that of the incoming Note value and whose zero-indexed MIDI channel matches the MIDI channel n of the incoming message. Velocity is used to set the LED colour.

Note Off — Turn off button LEDs

Hex version

Dec version

8nh, Note, Velocity

128+n, Note, Velocity

This message is interpreted as a note-on message with the same Note value but with a velocity of 0.

The Velocity byte is ignored in this message.

Launch Control XL Programmer’s Reference 4

Reset Launch Control XL

Hex version

Dec version

Bnh, 00h, 00h

176+n, 0, 0

All LEDs are turned off, and the buffer settings and duty cycle are reset to their default values. The

MIDI channel n defines the template for which this message is intended (00h-07h (0-7) for the 8 user templates, and 08h-0Fh (8-15) for the 8 factory templates).

Control double-buffering

Hex version

Dec version

Bnh, 00h, 20-3Dh

176+n, 0, 32-61

This message is used to control the double-buffering state of the buttons. The MIDI channel n defines the template for which this message is intended (00h-07h (0-7) for the 8 user templates, and 08h-0Fh (8-15) for the 8 factory templates). See the Appendix for more information on doublebuffering. The last byte is determined as follows:

Bit Name Meaning

6

5

4

3

2

1

0

Copy

Flash

Update

Must be 0.

Must be 1.

If 1: copy the LED states from the new ‘displayed’ buffer to the new ‘updating’ buffer.

If 1: continually flip ‘displayed’ buffers to make selected LEDs flash.

Set buffer 0 or buffer 1 as the new ‘updating’ buffer.

Must be 0.

Display Set buffer 0 or buffer 1 as the new ‘displaying’ buffer.

For those less familiar with binary, the formula for calculating the data byte is:

Hex version

Decimal version Data = (4 x Update)

where

Data = (4 x Update)

+ Display

+ 20h

+ Flags

+ Display

+ 32

+ Flags

Flags = 16 (10h in Hex) for Copy;

8 for Flash;

0 otherwise.

Launch Control XL Programmer’s Reference 5

The default state is zero: no flashing; the update buffer is 0; the displayed buffer is also 0. In this mode, any LED data written to Launch Control XL is displayed instantly.

Sending this message also resets the flash timer, so it can be used to resynchronise the flash rates of all Launch Control XLs connected to a system.

Turn on all LEDs

Hex version

Dec version

Bnh, 00h, 7D-7Fh

176+n, 0, 125-127

The last byte can take one of three values:

Hex Decimal Meaning

7Dh

7Eh

125

126

Low brightness test.

Medium brightness test.

7Fh 127 Full brightness test.

Sending this command resets all other data — see the Reset Launch Control XL message for more information. The MIDI channel n defines the template for which this message is intended (00h-07h

(0-7) for the 8 user templates, and 08h-0Fh (8-15) for the 8 factory templates).

Launch Control XL System Exclusive Protocol

Set LEDs

System Exclusive messages can be used to set the LED values for any button or pot in any template, regardless of which template is currently selected. This is done using the following message:

Hex version

Dec version

F0h 00h 20h 29h 02h 11h 78h Template Index Value F7h

240 0 32 41 2 17 120 Template Index Value 247

Where Template is 00h-07h (0-7) for the 8 user templates, and 08h-0Fh (8-15) for the 8 factory templates; Index is the index of the button or pot (see below); and Value is the velocity byte that defines the brightness values of both the red and green LEDs.

Multiple LEDs can be addressed in a single message by including multiple LED-Value byte pairs.

Indices are as follows:

00-07h (0-7) : Top row of knobs, left to right

08-0Fh (8-15) : Middle row of knobs, left to right

10-17h (16-23) : Bottom row of knobs, left to right

18-1Fh (24-31) : Top row of ‘channel’ buttons, left to right

Launch Control XL Programmer’s Reference 6

20-27h (32-39) : Bottom row of ‘channel’ buttons, left to right

28-2Bh (40-43) : Buttons Device, Mute, Solo, Record Arm

2C-2Fh (44-47) : Buttons Up, Down, Left, Right

Toggle button states

The state of buttons whose behaviour is set to ‘Toggle’ (rather than ‘Momentary’) can be updated by System Exclusive messages. This is done using the following message:

Hex version

Dec version

F0h 00h 20h 29h 02h 11h 7Bh Template Index Value F7h

240 0 32 41 2 17 123 Template Index Value 247

Where Template is 00h-07h (0-7) for the 8 user templates, and 08h-0Fh (8-15) for the 8 factory templates; Index is the index of the button (see below); and Value is either 00h (0) for off or 7Fh

(127) for on. Messages for buttons not set to ‘Toggle’ will be ignored.

Multiple buttons can be addressed in a single message by including multiple Index-Value byte pairs.

Indices are as follows:

00-07h (0-7) : Top row of ‘channel’ buttons, left to right

08-0Fh (8-15) : Bottom row of ‘channel’ buttons, left to right

10-13h (16-19) : Buttons Device, Mute, Solo, Record Arm

14-17h (20-23) : Buttons Up, Down, Left, Right

Change current template

The following message can be used to change the current template of the device:

Hex version

Dec version

F0h 00h 20h 29h 02h 11h 77h Template F7h

240 0 32 41 2 17 119 Template 247

Where Template is 00h-07h (0-7) for the 8 user templates, and 08h-0Fh (8-15) for the 8 factory templates.

4 Device-to-Computer messages

Button pressed

Hex version 9nh, Note, Velocity

Launch Control XL Programmer’s Reference 7

Dec version

OR

144+n, Note, Velocity

Hex version

Dec version

Bnh, CC, Velocity

176+n, CC, Velocity

Buttons can output either note messages or CC messages on a zero-indexed MIDI channel n. A message is sent with velocity 7Fh when a button is pressed; a second message is sent with velocity

0 when it is released. The editor can be used to change each button’s note/CC value and velocity value on press/release.

Template changed

Launch Control XL sends the following System Exclusive message out on changing template:

Hex version

Dec version

F0h 00h 20h 29h 02h 11h 77h Template F7h

240 0 32 41 2 17 119 Template 247

Where Template is 00h-07h (0-7) for the 8 user templates, and 08h-0Fh (8-15) for the 8 factory templates.

Launch Control XL Programmer’s Reference 8

Appendix — LED double-buffering and flashing

The Launch Control XL has two LED buffers, 0 and 1. Either one can be displayed while either is updated by incoming LED instructions. In practice, this can enhance the performance of Launch

Control XL in one of two ways:

1. By enabling a large-scale LED update which, although it could take 100 milliseconds to set up, appears to the user to be instantaneous.

2. By automatically flashing selected LEDs.

To exploit double-buffering for the first purpose requires very little modification to existing applications. It can be introduced in the following way:

1. Send Bnh, 00h, 31h (176+n, 0, 49) on start-up, where n defines the template for which this message is intended (00h-07h (0-7) for the 8 user templates, and 08h-0Fh (8-15) for the 8 factory templates). This sets buffer 1 as the displayed buffer, and buffer 0 as the updating buffer. Launch Control XL will cease to show new LED data that is written to it.

2. Write LEDs to the Launch Control XL as usual, ensuring that the Copy and Clear bits are not set.

3. When this update is finished, send Bnh, 00h, 34h (176+n, 0, 52). This sets buffer 0 as the displayed buffer, and buffer 1 as the updating buffer. The new LED data will instantly become visible. The current contents of buffer 0 will automatically be copied to buffer 1.

4. Write more LEDs to the Launch Control XL, with Copy and Clear bits set to zero.

5. When this update is finished, send Bnh, 00h, 31h (176+n, 0, 49) again. This switches back to the first state. The new LED data will become visible, and the contents of buffer 1 will be copied back to buffer 0.

6. Continue from step 2.

7. Finally, to turn this mode off, send Bnh, 00h, 30h (176+n, 0, 48).

Alternatively, chosen LEDs can be made to flash. To turn on automatic flashing, which lets Launch

Control XL use its own flashing speed, send:

Hex version Bnh, 00h, 28h

Dec version 176+n, 0, 40

If an external timeline is required to make the LEDs flash at a determined rate, the following sequence is suggested:

Turn flashing LEDs on Bnh, 00h, 20h (decimal version 176+n, 0, 32)

Turn flashing LEDs off Bnh, 00h, 20h (decimal version 176+n, 0, 33)

As mentioned previously, it is good practice to keep the Clear and Copy bits set while addressing

LEDs generally, so that an application can easily be expanded to include flashing. Otherwise, unintended effects will occur when trying to introduce it later.

Launch Control XL Programmer’s Reference 9