Controlling an FX MIDI unit

[trogluddite]

Took a look at the spec - it's actually pretty neat, it allows super-accurate 14bit values instead of the usual 0-127 range, which is quite unusual even these days.
I'll need to mod the RPN sender module to account for that, but it shouldn't be too hard to do - think I'll take the opportunity to convert those old SM modules to some nice FS Ruby code for a bit of extra control over the timing (the old ones used to send the values too quickly for some hardware devices to cope with properly).
Hopefully should have something for you later today....

[skull]

wow that would be great! I'm a designer, anything I can do for you just ask!

[trogluddite]

OK, I think I have it...

NRPN Skull.fsm

(131.94 KiB) Downloaded 930 times

I have tested this using a MIDI monitor, but I don't have any real kit that uses NRPN's, so you'll have to let me know how it goes.
I've wrapped my 'general purpose' NRPN module into a couple of slight variations for the different kinds of controls, so you should be able to see from the schematic how to use them.
However, I noticed something rather odd about the MIDI spec' sheet...
It says that it uses CC98 for MSB and CC99 for LSB. But that is exactly the opposite way around to the normal MIDI standards - so I'm not sure whether they are using those CC's in an unusual way, or whether it is maybe just a typo in spec's (this is VERY common in MIDI data sheets!).
So, if it won't work at first, try swapping the 'Address Page' and 'Address Number' inputs because it could be that they are back to front!
There's also a couple of parameters that you might need to tinker with...
1) Each NRPN sender has a 'delay' setting, to spread out the messages a little in case the hardware has a slow interface. Hopefully you shouldn't need it, but if the unit scrambles the messages you might need to slowly up the values in say 5-10ms steps.
2) The one for the knob has a 'Changes per sec' limiter so that is can't send way too much data. I've left it set at a very low value, so you might want to raise the 'FPS' value if you can hear the 'stepping' of the control values.

Hope that helps you get going, and thank for the offer with the graphics - there's always folks on the look out for a good GUI, so you'll be popular round here if you have those kind of skills (seems like it from the cool avatar!).

[skull]

Wow you are my hero! I think this is exactly what i'm looking for. Will give it a try and let you know how it works. Thanks again!

[skull]

Hi, I tryed it, but it seems like is generating random values... When I turn the know up, the values sent are like 25,100,12,46.... instead of 10.12.15.17.... hope you understand what I mean

[skull]

Hi, I disconnected the Changes per second, and the ruby code, and now works well, if I set the minmax in the knob from 0 to 127... I don't know whats going on here exactly, i'm pretty noob.

[trogluddite]

Hmm, that's interesting - certainly a number range problem, which is the aspect of the midi guide which is totally unclear.
Maybe if I clarify how I think it should be working that will help you to diagnose the problem a little bit...

1) The on/off one should be straightforward - just one or zero, not much to go wrong there (I hope!)

2) Exact number values - what the guide calls the "Switch or Section parameters". These should use the sender that I attached the 'selector' to, and would use the 0-127 range as you describe setting on your knob (deleting the Ruby from the 'knob' version make it the same as this one).

3) The knob one - for this one I tried to follow the description for "Continuous Parameters" - where it seems to imply that a 14bit value (0-16383) is equivalent to a 'fractional' value (presumably 0..1). For these kind of value the number has to be split into two parts (MSB, LSB) which I have done according to the MIDI spec. The little Ruby box was to apply this scaling for use with a un-edited 0...1 knob. But their description is pretty vague, so possibly I've made some wrong assumptions here.

So, as I made it, using the 'knob' sender with a parameter that expects 'Switch/Section parameter' numbers would indeed act a little oddly. However, I'm not totally sure that this is what you are describing, so let me know if the above description makes sense.

It's a shame they don't put as much effort into their MIDI spec's as they do with the cool hardware - I noticed several other bits of weirdness in that manual (e.g. it says that dataLSB is CC number 38 (decimal) then later says it is $38 (hexadecimal) - it can't possibly be both, but the MIDI standard of decimal 38 seems to be right if your 0..127 knob is working).

[skull]

Thanks! I will check all of this and get back. I'd contacted with their support, but they seems to be protecting something, haha I don't understand why they are so cryptic with a simple midi specs. Also this device doesn't send midi data, only receive it at this moment...

[skull]

Hi! they released a new midi spec doc, where it seems to accept now sysex and also sends data...
I'm trying to figure out how this works, because it seems that they have some bugs, the unit hangs...

You can take a look at the attachment. I searchd for a sysex sender, and also used a program, but I can get response.. Maybe can you help me with this? Btw I'm doing some 3d knobs, I will share here when I finish them, also attached a picture of the progress ¿what do you think?

[skull]

Here is a render of one knob i'm doing.