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Possibility for midi router?


basta73

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Would it be possible to utilize the MIOS platform to create a MIDI router?  

8*8, ins & outs, like MIDEX8 or MoTU Midi Express lines.  I think this may have been proposed before, but I could not find any info on it.  I bring this up because of the low latency achieved by these projects.  Anyone else interested in this?

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  • 2 weeks later...

Most PIC controllers contain only one UART which can be used as a MIDI interface. Alternative DIY friendly chips are hard to find and require different programming (=burner) and development tools.

A solution could be a board with 8 smaller PIC derivatives (i.E the 16F627), which are attached to a parallel bus for an uncomplicated and fast exchange of MIDI messages. However, if somebody builds me such a board (based on my schematic) I would be able to realize the appr. firmware very quickly. But so long as I have to build the board by myself, it could take much longer (due to higher priority tasks ;-))

Best Regards, Thorsten.

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Guest linenoise

excellent thorsen...

now whos the electronic genius who is going to help out?  i would but you may end up with a really nice midibox toaster =-D (not very good with electronics).

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Hi Kent,

alright, a preliminary schematic can now be found here:

http://www.ucapps.de/tmp/midi_router.pdf

It's a simple master-slave design. Every slave acts as a IO device and provides a Tx buffer of 64 bytes and Rx buffer of 128 bytes. The slave firmware will be so simple, that it never has to be updated again, therefore a programming socket is not required. The brain of the system is a PIC18F based core which accesses the PIC slaves over a parallel bus. A handshake protocol (Request/Acknowledge scheme) ensures that only one PIC drives the bus at one time. Up to 8 slaves can be connected. The 100k terminators at the end of the bus ensure proper signals for fast accesses (like SCSI). The master core will cyclicaly request every slave for new data. Incoming data streams can be filtered, merged, converted and routed to any MIDI Out(s)

Best Regards, Thorsten.

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Hi Kent,

the layout look really great! But I would propose to mount 4 or 8 slave PICs on one board in order to reduce a lot of wiring effort. The junction to the core module should be 1:1 (same pinning like J5/J6/J7) to simplify the soldering. Also the pinning of the MIDI junctions should be the same like CORE:J12 and CORE:J13 so that connectors can be exchanged for testing if necessary.

Best Regards, Thorsten.

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BTW. A litthe idea.

What about making a master with the comming PIC with USB interface, and "upti" (danish expression) we have a USB MIDI inteface with 8 in, 8 out and all sort off filter, merge, translate .........

one after another... ;-)

Best Regards, Thorsten.

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Hey Thorsten

About the PCB Board:

I can make a board with 4 or 8 PIC on (I think I prefere one with 4 so you can stack them), but it will have alot of wire on it. I will then put then side by side.

The reason to make a board with just 1 PIC was the easy connection between then, you just use a cable with 20 wire and 8 IDC connector (like IDE HD cable) to connect them together without soldering. Only the end going to the core have to be solder.

Look at this:

connection.jpg

Let me hear what you think. (keep or make one with 4 PIC)

I will change the MIDI connector so its the same as the core modul.

Kent

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Hmmm.. the long cables could decrease the max. data transfer rate due to additional capacities, so that I would prefer a 4-slave board. Ok, this could be connected with an IDE cable to the core module (nice idea!)

Best Regards, Thorsten.

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Guest Johannes

Nice project, I'll definitly build one sometime coz at the moment I only have 1in/1out on my card and as Thorsten seems not to stop building new Controllers  ;D ;D ;D and stuff this is THE perfect solution for an interface to my PC.

MMM: really astonishing work in that short time and your idea to connect the boards via IDE cable is really great!

greetz

Johannes

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Hey again

Here is another way to connect the single board version:

connection2.jpg

By doing it like this the lenght of the wire is only about

20cm (7 x 15mm + 90mm from last board to core).

A board with 4 slaves on will at least have the same lenght of copertraks.

Btw. normal IDE cable are used up to 66MHz.

But, Thorsen I have started making a board with 4 slaves on, but it will take some days to finish.

(I am also working on boards for my LC clone) ;D

To all, thanks for the nice words. :)

Kent

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