184 lines
6.2 KiB
Markdown
184 lines
6.2 KiB
Markdown
# mustang-midi-bridge
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Allow Fender Mustang series guitar amplifiers to be controlled by MIDI
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messages
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# What's New
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Complete rewrite and restructure of code based on ever-increasing
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familiarity with the Mustang communication protocol and API. The
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bridge code is now fully mulithreaded. A persistent background thread
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is constantly listening to incoming traffic from the amp and updating
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shared data as necessary. This greatly increases stability and makes
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the bridge tolerant of manual adjustments on the amplifier while
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nominally under MIDI control. In particular, it is now possible to
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engage the tuner function on the amp without ill side-effects.
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The command line parameter for MIDI controller port is now assumed to
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start at 0 rather than 1 in order to match the way Linux ALSA
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enumerates devices (see 'Run' below).
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I have added the first version of a runtime framework that starts and
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stops the program automatically based on attached MIDI devices. This
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seems to be working on a Beaglebone SBC, but has not been extensively
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tested or documented yet. There is a small amount of customization
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required to account for your specific amp model and MIDI controller
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interface. Technically oriented users can probably work this out,
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otherwise wait a bit until I can refine the packaging and arrange to
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have the various pieces configured from a common setup file.
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You can still invoke the bridge on the command line, but there will be
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no output to the console and it no longer responds to keypress
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input. Enter Ctrl-C (SIGINT) to exit.
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Support added for amp and effects models specific to the Mustang v2
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products. This has had only limited testing.
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Added a python script to drive regression testing.
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# Introduction
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Mustang bridge implements about 99% of the published MIDI spec for the
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Fender Mustang Floor pedal with extensions to support features added
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to the 'v2' series.
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I am developing on a Ubuntu Precise desktop machine, but the code is
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routinely tested on a Raspberry Pi 'B' and Beagelbone Green to ensure
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these remain viable deployment targets. At this point I'm still
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experiencing issues with USB latency on the RPi and am currently
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recommending the BBG for real-world use.
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Special thanks to:
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+ The original developer and contributors to 'PLUG' who blazed the
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path with reverse-engineering of Fender's communication scheme.
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+ Robert Fransson (Codesmart on VGuitar Forums) for feedback and
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encouragement - and for being a tireless programming wizard :-).
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+ Robert Heitman, author of the Android 'Remuda' application for
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Mustang amp control, who provided valuable insights into various
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subtleties that would have otherwise escaped me.
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## For the non-techies
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I have written a Wiki page here:
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https://github.com/snhirsch/mustang-midi-bridge/wiki/Install
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that attempts to walk less technical users through the installation
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and build process on Raspberry Pi or Beaglebone. It's hard to know
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what level of detail to hit and suggestions or comments would be
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appreciated if I've omitted or glossed over something critical.
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# Status
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The Mustang Floor MIDI spec is about 99% implemented, with only the
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following exceptions:
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+ Amp Bypass
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It's possible to turn the amp "off" with CC#68 0, but this mutes
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all sound rather than acting as a bypass. It appears that the
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combo amps do not support the notion of straight-through routing
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without an amplifier modeling block.
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+ Pedal Volume
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I'm not sure why this would even be needed, since all continuous
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controllers are directly accessible through CC messages.
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+ FX Insert
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Not supported on the combo amps.
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+ Tap Tempo
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If I can figure out how to do this from FUSE I can code it.
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I'm using USBPcap and tshark to snoop communication and plan to
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implement all features accessible from the Fender FUSE application.
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However, some targets listed in the MIDI spec (e.g. amplifier on/off,
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tuner mode) are not controllable from FUSE and it may take some time
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and luck to figure out the protocol.
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# Prerequisites
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+ For Ubuntu Precise or Debian Jessie:
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- libasound2
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- librtmidi-dev
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- libusb-1.0-0-dev
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- libjack0 (Precise)
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- libjackQ (Jessie)
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+ If you want to run the regression tests, you'll also need:
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- python2.7
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- python2.7-dev
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- python-pip
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- 'Mido' Python MIDI extension
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- Python rtmidi extension
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'mido' and rtmidi are not available as a DEB package and must be
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installed using 'pip':
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$ pip install --pre python-rtmidi
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$ pip install mido
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Would appreciate feedback on requirements for other distributions.
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# OS Configuration
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+ Add the id of the user who will be running the bridge to the
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'audio' and 'plugdev' groups. That user should then log out and back
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in to make the groups effective.
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+ As root, copy the file '50-mustang.rules' to /etc/udev/rules.d and
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refresh the system with 'udevadm control --reload'.
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There may be slight differences in requirements for other distributions.
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# Build
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```
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$ make opt
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```
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or
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```
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$ make debug
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```
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as appropriate
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# Run
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Both the amplifier and MIDI source should be connected first, then:
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```
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$ mustang_midi midi_port# midi_listen_channel#
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```
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NOTE1: I'm not sure about other platforms, but on Linux the MIDI
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port number is equivalent to the ALSA card index. I had originally
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treated port as 1..n, but since ALSA (and JACK? Not sure..) starts at
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0, this has now been changed. You can find the card index for your
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controller by connecting it to the computer and examining the
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pseudo-file, e.g.:
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```
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$ cat /proc/asound/cards
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0 [PCH ]: HDA-Intel - HDA Intel PCH
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HDA Intel PCH at 0xf7530000 irq 30
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1 [Interface ]: USB-Audio - USB MS1x1 MIDI Interface
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M-Audio USB MS1x1 MIDI Interface at usb-0000:00:14.0-1, full speed
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```
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To accept MIDI messages from devices behind the M-Audio interface you
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would now specify '1' as the MIDI port value.
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NOTE2: RPi and BBG are a bit fussy about enumeration of new USB
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devices. If you are not getting proper communication, quit the program
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and try replugging both the Fender amp and MIDI controller **after**
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those devices are powered up.
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NOTE3: I've had success using a passive USB hub with the single USB on
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the BBG, but YMMV since most USB<->5Pin MIDI converters draw some
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degree of bus power. A powered hub might be necessary in some
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situations.
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