simple MIDI to CV w/o using a PIC...possible??

[jadesky]

hi,

so i was wondering if there is a very simple, rudimentary way to convert a MIDI signal to CV.  Very specifically, what I want to do is have a "clock in" for an analog sequencer so its speed can be controlled my a MIDI clk out. Is there any way to do this without having to mess with PICs?  I have a feeling not, but I thought I'd ask anyway.  I saw some interesting suggestions using LDR's and LED'S, etc., but that particular project still required harvesting already existing MIDI components.  I'm looking for a circuit/trick of somesort that will serve as the entire "black box" between the clk out of a MIDI device and the clk in of a sequencer. 

If you do need a PIC to do this and there's no way around it...well...I've never even messed with PICs before so maybe someone can streamline me in the direction to just quickly learn enough to be able to pull just this specific project off?  I know that's asking a lot, but it doesn't hurt to ask anyway.

Thanks a lot . 

[Dave_B]

IIRC, I've seen circuits that use shift registers for doing simple MIDI clock processing.  Not sure where they are now, unfortunately.

On the other hand, depending how big a hurry you're in, you may have a few volunteers here in the next couple of months. 
In fact, if you're interested in learning about microcontrollers, you're showing up at the perfect time.  A lot of us are buying programmers at the moment so we can all learn this stuff together (though on a different brand).  I'm sure a few of us have ideas that involve MIDI.  I know I do.  If it's at all encouraging, in one month I learned enough about PICs to build some pretty cool stuff.  You CAN learn just what you need to, to an extent.

If that's boring you, you might have some luck looking on the various DIY Synth sites.  You might even find someone on AVRFreaks.com to help.

[Unbeliever]

What sequencer are you using?

http://www.musicfromouterspace.com/analogsynth/midi2cv.htm

However, this only does MIDI note on / off information -> CV. Depending on the sync options on your sequencer (eg if there is a trigger input for restarting the sequencer cycle), you could use this circuit and send a particular MIDI note along (say one that maps to greater than +5V or +10V at the destination for the trigger) when you need to restart / sync your sequencer. If your time is worth more than a few $ per hour a commercial offering would make more sense though.

edit: the extra circut mentioned on that page provides trigger and gate out, so NO need to pick a particular note.

[Paul Perry (Frostwave)]

I think someone on this board did a UART based midi clock detector, way back in the dark ages.
Personally, I'd buy a pre-programmed midi-din converter PIC from Blacet Research! http://www.blacet.com/misc.html

[Dave_B]

Personally, I'd buy a pre-programmed midi-din converter PIC from Blacet Research! http://www.blacet.com/misc.html

Good call, Paul.  I forgot all about Blacet.  I almost bought his rack mount system last year to put my guitar effects in.

[Mark Hammer]

Near as I can tell, that chip only deals with timing information, and will not put out the cv, gate and trigger information that is likely desired by jadesky.  The "something happened" information seems fairly easy to decode, but the "what happened?" information requires more complex interpretation, delivered either by a PIC or some other sort of microcontroller.  Trouble is that the pitch information (represented by the CV in the analog domain) is conveyed in the midst of a stream of digital info.  Knowing *where* in that stream, and treating the information provided in that steam in a different way just for that little sub-bundle, requires intelligent processing, as opposed to "dumb" processing.

[R.G.]

Mark is completely right. There is no practical way to do this without some intelligent clot of logic to identify the proper information and make it into a voltage.

It is, however, trivial to do with a uC of any stripe.

[Dave_B]

He mentioned only needing clock info.  Since the Blacet chip puts out 24ppq pulses based on the MIDI clock coming in, wouldn't that do the trick?

[Maneco]

http://www.colinfraser.com/m2d/m2d.htm

works great!

[Maneco]

http://www.angelfire.com/geek/srlabs/diner.html

not tested by me...

[Maneco]

..l know all of this use a pic,but they are extremely simple...

here's a sequencer to have fun with the received clocks...

http://www.hoohahrecords.com/resfreq/modular/patseq/patseq.html