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By Gustavo Bravetti
#191769
Hello, I hope you can help me to find some light on this issue I'm experiencing.

I have an Arduino based device that speaks MIDI.
it sends 10 MIDI CCs (20-29 channel 8 ).

The MIDI circuit schematic is the one suggested here: https://www.arduino.cc/en/Tutorial/Midi

The data produced by the Arduino device is interpreted correctly by all of my MIDI interfaces... with the exception of my iConnect MIDI 2+.

On the iConnect MIDI 2+ interface the CCs are not interpreted well at all. Instead, unexpected data is interpreted bye the iConnect MIDI2+ like: Pitch Wheel, Tune Request, Song Select, Clock, Note On, Program, Stop, Chan Pressure, etc.,.

Now if I use a Quadramerge (or a Quadrathru) box (a MIDI merger box), in the middle of the connection, all data is correctly interpreted by the iConnect MIDI2+.

I was advised to place on the MIDI circuit a 0.1µ capacitor between TX and Ground but that didn't fix it.

After some tests what actually almost did fix it, was to place a 1µ (or bigger) capacitor on the MIDI circuit between v+ and ground. By placing this capacitor I have like 95% expected data and just a very few unexpected. May be this could be something related to the power source?

UPDATE: I did completely clean the signal adding besides the 1µF capacitor, a 10k resistor between TX and Ground on the MIDI circuit. Does it makes any sense?

I'm using the FTDI-USB cable to power the device, connected to a 20W iPad USB charger.
Connecting the FTDI-USB cable to other power sources (PC, Powered HUB, etc), didn't fix the issue, also there is a noticeable difference on the unexpected data.

So far this is not a deal breaker cos I can use the MIDI boxes to fix the signal, or the capacitor to get almost clean data, then even use the boxes, post MIDI data filters etc, but it will be nice to know the proper way to get the expected data from start.

Actually the most urgent matter is to know if that 1µ capacitor placed between the V+ and Ground on the MIDI circuit could be armful in any way for the Arduino, or the power source, or the connected MIDI interface.

Thanks in advanced,
Gustavo