+
overview
+ is a compact and versatile
6-way MIDI splitter
and
MIDI beat clock generator
.
It was designed to be "hands on" and was developed with
MIDI jam sessions in mind, but is a versatile tool in any
MIDI setup.
+ is open hardware, with open source firmware
code. For more information please visit
https://github.com/hotchk155/MIDI-Hub/wiki
hardware
Power:
The hub is powered via the mini USB connector. You
can connect it to a computer, a powered USB hub, or to a
standard 5 volt USB charger/power supply.
USB is for
power only, no drivers are required and the device will not
show up to your operating system.
MIDI:
The hub features a single MIDI input (opposite the
USB connector) and six identical MIDI outputs. Notes, etc,
received at the input will be sent to all outputs.
LEDs:
The function assigned to each of the six LEDs
depends on the selected mode and is described below.
Buttons:
The top button (PLAY) is used to start and stop
the MIDI clock function. The lower buttons (MINUS and
PLUS) are used to change the clock rate. Each button has
additional functions described below.
Programming Port
: The row of holes below the USB
connector allow reprogramming of the firmware loaded on
the hub's PIC16F1825 microcontroller. A suitable PIC
programmer is needed (e.g. PICKit2)
operating modes
BPM Mode
: The hub powers up in this mode, starting in the
paused state. When paused, four of the LEDs blink at the
selected BPM. The initial BPM is 120.
Press PLAY to start the hub running. When running, all six
LEDs illuminate in cycling pattern at the current BPM. Press
PLAY again to pause the hub.
When running, the hub sends MIDI TICK messages to all six
outputs at the selected BPM. Appropriately connected and
configured MIDI devices that support MIDI sync will
synchronise their playback to these messages. The hub also
sends a MIDI START message when it starts running and a
MIDI STOP message when paused.
At any time when in BPM mode, the MINUS and PLUS
buttons can be used to change the BPM in +/-1 BPM steps.
The buttons auto-repeat when held for about 1 second.
Press both buttons together to reset the BPM to 120.
BPM can be adjusted from 30-300bpm and is approximate
(according to accuracy of PICs internal oscillator)
Press and hold the PLAY button for 2 seconds to "lock" into
running mode. Now when PLAY is pressed, a MIDI START
message is sent without stopping playback. This can be
useful for resynching newly connected MIDI instruments to a
common start point. Press and hold PLAY again to return to
normal start and stop mode.
Tap Tempo Mode:
To enter Tap Tempo mode, hold down
MINUS and immediately press and release the PLAY button.
Now tap the MINUS button at the desired tempo, tapping
between 2 and 6 times (more taps will increase the accuracy
of the input). The LEDs will count up each tap and the tempo
will be adjusted as you tap.
Tap tempo mode is effective until you press the PLUS
button. You can make multiple tap tempo inputs without
having to repeat the MINUS>PLAY combination.
Split Only Mode:
In this mode, the hub does not generate
a midi clock, but continues to split the MIDI input to the
outputs. The LEDs glow to "visualise" the MIDI data..
To enter Split Only mode, hold down PLUS and immediately
press and release the PLAY button.
Pressing PLAY in this mode sends a MIDI START message to
connected devices.
Pressing PLUS alternates between sends a MIDI STOP or
MIDI CONTINUE (if STOP was previously sent). This is useful
if you have an external master MIDI clock which does not
easily allow START/STOP messages to be sent.
To exit Split-only mode and re-enable the clock, press the
MINUS button.
Options Menu:
To enter the Options Menu, press the
START/MINUS/PLUS buttons together.
Settings are mapped to each of the six LEDs according to
their position as follows:
Allow MIDI realtime
messages (e.g. clock)
to pass from input to
output (default: OFF)
Select LED brightness level
from one of six options.
(default: Maximum)
Allow non-realtime MIDI
messages (e.g. Notes, cc)
to pass from input to
output (default: ON)
Enable "quiet mode", which
uses only the top two LEDs
as indicators in clock mode.
(default: OFF)
Send MIDI START and
STOP messages in clock
modes (default: ON)
Enable the "visualisation"
of MIDI thru traffic in split-
only mode (default: ON)
Press PLUS to select a setting (indicated by the flashing of
the corresponding LED) and Press MINUS to select between
values (ON, OFF or brightness level). Press PLAY again to
exit from the menu.
MIDI Thru:
MIDI thru (from input to outputs) is active at
all times, except when specifically disabled via the options
menu.
