Adding a 2nd MIDI input

Design Concepts
1

I’m looking for suggestions on how to implement a second MIDI input on my midibox.

I’ve nearly completed all the software for my custom midibox. It is a remote programmer for a Oberheim Matrix 1000 synthesizer.

It works by passing note on/off data from its MIDI IN, and adding sysex data to its MIDI out onto the Oberheim’s MIDI in.

One important feature is the ability to synchronize the edit buffer of the Oberheim to the edit buffer of the Midibox.

When a program change is issued from the Midibox, it also requests the edit buffer of the oberheim. The edit buffer is sent from the Oberheim MIDI out and sent back to the Midibox where the data is displayed and handled.

Currently, I have this working through my laptop with MIDI-OX using the PASS SYSEX feature to route the sysex data from the Oberheim back to the Midibox.

Using my laptop is not ideal obviously. I need to implement this two-way communication using just a keyboard like so:

[KEYBOARD]-->[MIDIBOX]-->[OBERHEIM]

                 ^ |

                 | ____________ |

If I could add an additional MIDI input to my Midibox, it would resolve the cabling issues.

But according to the docs I’ve read, it’s not possible.

I’m currently using 1 pic 18f4620 core, 1 ain, 1 din, 1 dout.

It looks like a Midimerger with some MIDI filtering might do the trick. If so, I’d like to build it inside by current project, using the same power source.

If not, I guess I could build an outboard Midimerger.

Can anyone suggest a way I can get the Midibox communicating both ways with the Oberheim and still have a keyboard connected?

2

I’m looking for suggestions on how to implement a second MIDI input on my midibox.

I’ve nearly completed all the software for my custom midibox. It is a remote programmer for a Oberheim Matrix 1000 synthesizer.

It works by passing note on/off data from its MIDI IN, and adding sysex data to its MIDI out onto the Oberheim’s MIDI in.

One important feature is the ability to synchronize the edit buffer of the Oberheim to the edit buffer of the Midibox.

When a program change is issued from the Midibox, it also requests the edit buffer of the oberheim. The edit buffer is sent from the Oberheim MIDI out and sent back to the Midibox where the data is displayed and handled.

Currently, I have this working through my laptop with MIDI-OX using the PASS SYSEX feature to route the sysex data from the Oberheim back to the Midibox.

Using my laptop is not ideal obviously. I need to implement this two-way communication using just a keyboard like so:

[KEYBOARD]–>[MIDIBOX]–>[OBERHEIM]

^ |

| ____________ |

If I could add an additional MIDI input to my Midibox, it would resolve the cabling issues.

But according to the docs I’ve read, it’s not possible.

I’m currently using 1 pic 18f4620 core, 1 ain, 1 din, 1 dout.

It looks like a Midimerger with some MIDI filtering might do the trick. If so, I’d like to build it inside by current project, using the same power source.

If not, I guess I could build an outboard Midimerger.

Can anyone suggest a way I can get the Midibox communicating both ways with the Oberheim and still have a keyboard connected?

Most PICs have only one UART/USART/AUSART (serial port).. so only one MIDI IN and one MIDI OUT.

You can add another of each by adding an IIC MIDI Module, which adds another in and out..

OR you can promote to a core32, which has 2 MIDI INs and 2 MIDI OUTs..

It’s a start!

LyleHaze

3

don’t forget usb :slight_smile:

4

You can add another of each by adding an IIC MIDI Module, which adds another in and out..

LyleHaze

LyleHaze

I never paid any attention to the IIC MIDI Module. According to the docs, it looks like a good idea but will require additional software on my part in order to read from the 2nd midi input. Am I reading it wrong?

However a MIDI merger wouldn’t require any software changes and still give me two inputs which is exactly what I need.

The second input would be used to connect the Oberheim out back to the Midibox so I can receive its sysex data… which is all that would ever be sent.

5

LyleHaze

I never paid any attention to the IIC MIDI Module. According to the docs, it looks like a good idea but will require additional software on my part in order to read from the 2nd midi input. Am I reading it wrong?

However a MIDI merger wouldn’t require any software changes and still give me two inputs which is exactly what I need.

The second input would be used to connect the Oberheim out back to the Midibox so I can receive its sysex data… which is all that would ever be sent.

OK, now you hurt the IIC modules feelings.. it’s little silicon heart is breaking..

I can’t give details as I have never used it. Yes, a bit more software, but I think you’ll find all the tough stuff is already done for you. (TK is really good that way)

Yes, an external merger would work as well.

I wonder how the cost of a commercial MIDI merger would compare to the cost of a core8 and an IIC module?.. Or the cost of a Core32?

I’m just pointing out that if you want control over HOW the streams are merged, you’ll need an “open” design like we have here.

In any case, have fun!

LyleHaze

6

I’m just pointing out that if you want control over HOW the streams are merged, you’ll need an “open” design like we have here.

Thanks again LyleHaze

I understand, I may have mispoke about the filtering MIDI in the original post. I can easily filter now what coming in on the MIDI in jack right now. I gues all I need is a merge on one MIDI in.

Considering my inherent lazyness, I’ll go for the easiest solution possible.

To buy a MIDI merger on the market would cost me as little as $60 USD new, maybe a lot cheaper used on eBay.

A lot of them require no additional power supply to make them work.

I’ve not decided yet. It still may be an option.

7

I think Lylehaze has hit the nail on the head, you can do some really complex merging/routing with MIDIbox. Have you looked at the Midi Router project?

http://www.ucapps.de/midi_router.html

It supports up to 4 IIC modules for a total of 5 MIDI IN/OUT ports and can be easily modified (with C knowledge) to merge/route between any combination of devices. An off the shelf MIDI merger is usually pretty dumb…

Phil