MIDIbox CV V2 Concept

[TK.]

I added some new features today:

 

- the Lemur panel has been overworked, so that global parameters (outside the CV groups) are now accessible with the "G" button at the right side.

 

- added "Force To Scale", which can either be activated at the end of the CV output data streams, or "in between" by using the modulation matrix.

The Force To Scale works like a Quantiser which allows to select the note values which should be played - all other notes are forced to the neighbored selected note:

 

In this example: only D# will be played, all other notes are forced to D#

 

In order to use Force-to-Scale, either push the "Force Scale" button in the Main panel, or select the "FTS" operator in the modulation matrix.

 

- support for analog inputs: STM32F4 all 8 inputs at J5A and J5B, and LPC17 currently only J5B.A4 and J5B.A5 (since J5A is used for OLEDs) - later it will be possible to use J5A as well for people who don't use the OLEDs on a LPC17 core

(again: there is no limitation for the STM32F4 core)

 

AIN inputs can be selected as source in the modulation matrix.

 

In addition, AIN inputs can be used as external gates, e.g. to trigger the LFOs and Envelopes.

In order to activate this function, change to the main page and increase the "Ext. Gate Threshold" value at the left side, which defines the level at which the gate will be triggered.

 

- the envelopes got new curves (Exp1, Exp1Inv, Exp2, Exp2Inv), and it's possible to select different curves for rising and falling ramps:

 

(inspired from the Andromeda synth as demonstrated by Hawkeye! :smile:

 

- the modulation matrix got an offset parameter to increase/decrease the modulation path output:

 

 

Unfortunately these changes lead to incompatible patches.

Since there aren't so many users yet, I haven't worked on a translator -> your old patches will be corrupted (in the ENV and MOD sections).

If you don't mind, just delete the old banks with the MIOS Filebrowser (remove MBCV_B1.V2 ... MBCV_B4.V2)

Thereafter enter "reset" in the MIOS Terminal so that new banks are created.

 

Please also note, that the updated Lemur panel has to be used as well with the new firmware, otherwise the parameters are not correctly mapped.

 

Best Regards, Thorsten.

[sneakthief]

TK strikes again.

 

Der Hammer!

[latigid on]

Wow, looks awesome!

 

So, now we have a gate to MIDI converter -- any thoughts on CV-MIDI conversion at 1 V/octave?

 

With the AIN scaling/protection circuits it seems to be difficult to decide on one standard, so I propose on a final panel a mixture of 0-5, 0-10 and -5 to +5 inputs, hopefully that's workable with the correct offsets. Alternatively each input could have an attenuator:

 

http://www.falstad.com/circuit/#%24+1+4.9999999999999996E-6+47.65948060424672+58+15.0+60%0Ar+640+352+704+352+0+20000.0%0Az+912+352+912+304+1+0.805904783+3.3%0Az+912+400+912+352+1+0.805904783+3.3%0Ag+912+400+912+432+0%0AR+912+304+912+272+0+0+40.0+3.3+0.0+0.0+0.5%0AR+400+336+368+336+0+4+50.0+10.0+10.0+0.0+0.5%0Ap+912+352+960+352+1%0Aa+528+352+624+352+0+15.0+-15.0+1000000.0%0Ag+528+368+528+400+0%0Ar+528+336+480+336+0+20000.0%0Ar+464+336+400+336+0+20000.0%0Ar+496+432+496+496+0+100.0%0Ar+544+304+592+304+0+20000.0%0Ar+592+304+640+304+0+20000.0%0Aw+640+352+624+352+0%0Aw+528+336+528+304+0%0Aw+528+304+544+304+0%0Ag+400+432+400+448+0%0Aa+736+352+816+352+0+15.0+-15.0+1000000.0%0Aw+736+368+736+400+0%0Aw+736+352+736+336+0%0Ag+736+400+736+432+0%0Aw+736+352+704+352+0%0Aw+736+336+736+288+0%0Ar+736+288+832+288+0+20000.0%0Aw+816+352+816+320+0%0Aw+816+320+832+320+0%0Aw+832+320+832+288+0%0Aw+640+352+640+304+0%0Ar+816+352+912+352+0+100.0%0A174+400+368+448+432+0+10000.0+0.9455000000000001+Resistance%0Aw+480+336+464+336+0%0Aw+464+400+464+336+0%0Aw+464+400+448+400+0%0Ao+5+64+0+39+20.0+0.0015625+0+-1%0Ao+6+64+0+38+5.0+9.765625E-5+0+-1%0A'>Falstad sim, never a bad thing with modular patches.

 

 

 

 

[sneakthief]

latigid on: for CV to MIDI conversion, theoretically you just need the 1/3 voltage divider and input protection circuit to handle 0-10V (which is the most typical CV range for VCOs, eg. the range put out by almost all CV step-sequencers). Not only that, if you look at the Mod-Matrix picture above, you can see that there's an Offset and Depth control. It seems you can take the analog input and tweak its response further and likely get very good 1V/Oct scaling.

 

I got most things assembled and connected yesterday and everything looks good:

 

 

 

The only weird thing so far is when I turn CV1 ENV2 Offset past 127 it suddenly skips to 65535 and stays there. I bet it's a configuration error.

 

Today I'm going to hook up the SCS and OLEDs.

[latigid on]

sneakthief, I see some issues with one standard of input: If a bipolar CV (like an LFO) is plugged in, the negative portion of the waveform will be clipped to ~0 V by the Schottky diode. Also for nominal signals of say 0-5 V you lose half the ADC resolution as the full scale input is 10 V. But the option should be there to choose your own pre-ADC treatment. I will get around to a board layout at some point, just a bit busy at the moment.

[sneakthief]

 Making eight +5V level shifters isn't that complicated for those that want such a feature.

 

This has already been discussed here:

 

FWIW: There are no midi quantizers I can think of that output negative voltages. Perhaps 10% of quantizers accept +/-5V. Some would consider this the job of a CV level-shifter module...

Edited February 23, 2014 by sneakthief

[sneakthief]

TK - For the sequencer, would it make sense to blink one of the encoder-ring LED's as a step-chaser that follows the pattern, like in this video?

 

[eptheca]

quick newbie question:

 

I can save the patch, and I can see/read the file in the MIOS file browser, but when I press LOAD on the unit I get <no .MIO files>

 

any suggestions?

[TK.]

For the sequencer, would it make sense to blink one of the encoder-ring LED's as a step-chaser that follows the pattern, like in this video?

 

I guess that you are mainly searching for some „blink“.

Well, I consider to display animated output waveforms of the controlled parameters in future! :smile:

E.g. LEDrings should be animated based on the LFO and ENV depth parameter assigned to the corresponding encoder.

 

 

I can save the patch, and I can see/read the file in the MIOS file browser, but when I press LOAD on the unit I get <no .MIO files>

 

This was a bug (now fixed in the repository)

Actually the LOAD page should search for .CV2 files, and not .MIO files

 

Best Regards, Thorsten.

 

[sneakthief]

Well that's certainly a good way to approach visual feedback on the sequencer!

 

I guess that you are mainly searching for some „blink“.

Well, I consider to display animated output waveforms of the controlled parameters in future! :smile:

E.g. LEDrings should be animated based on the LFO and ENV depth parameter assigned to the corresponding encoder.

[novski]

@sneakthief; wold you share the schematic of that MIDI I/O board? 

[sneakthief]

Novski: I don't have any schematics for that - it's a beta unit that TK sent me. I'm sure it will be published quite soon.

[eptheca]

I have problems saving settings.

I want to save Slew Rate for the different CV channels, for use with CC

I also want to save Mode:CC and CC number for each CV channel

 

None of these settings are saved in the Patch.

The only thing that I have changed, that is saved is Scope settings.

 

Can I force these settings from editing the files before compiling?

 

I'm using it live tomorrow :/

 

Cheers

[TK.]

Currently only the global settings can be saved from the SCS.

Patches can only be saved from the Lemur patch.

 

As I can see, there is still some work for a public release... :-/

 

Best Regards, Thorsten.

[eptheca]

Ok.

But is it possible to force the settings before compiling or upload them as sysex?

Best regards

Halvor

[TK.]

Not really (too difficult)

 

I could provide a save_patch and load_patch command in the terminal if this helps

The first patch will be loaded automatically after startup - and will then contain your default settings.

 

Best Regards, Thorsten.

[eptheca]

That would be great. :)

Best regards

Halvor

[Imp]

I just tried to download the lemur template from http://svnmios.midibox.org/listing.php?repname=svn.mios32&path=%2Ftrunk%2Fapps%2Fprocessing%2Fmidibox_cv_v2%2F.

It gave me an error: "Unable to open file: MIDIbox_CV_V2.jzml.r1982"

As a quick workaround i copied the code as text and pasted it to a file. Lemur seems to be ok with that.

But what went wrong? Do i need something else?

[TK.]

Today I spent some hours to make the WebSVN download button working - without success!

This seems to be related to some webserver security settings. Due to my limited knowledge about such topics (I don't want to open a security hole!!!), I've disabled the download button now.

Only proper way to download files is via a SVN client, such as Tortoise under Windows, or "svn" under MacOS/Linux.

 

 

Currently only the global settings can be saved from the SCS.

 

With the latest sources we are now able to save/load patches from the SCS! :)

• move the SCS encoder or trigger GP button #2/3 to select the current patch
• store/load a patch under Menu->Disk->Patch
• A001 is loaded after startup

Best Regards, Thorsten.

[eptheca]

With the latest sources we are now able to save/load patches from the SCS! :smile:

• move the SCS encoder or trigger GP button #2/3 to select the current patch
• store/load a patch under Menu->Disk->Patch
• A001 is loaded after startup

Best Regards, Thorsten.

 

Great news to wake up to :)

 

Thanks again TK

 

Best regards

Halvor

[Phatline]

is there a possibility to change the Note/Frequency Calculation? Change to a indian System where the Octave is splited in 22 Tones, where the notes and its frequencys are stored in tables - not all of the 22notes are used, some are taken for a song - this selection is for playing a "Raga"...

In which part of the Application is this Calculation, and where I could put tables instead (note 1 is predefinied frequency > variable > integer...)

[TK.]

It's started, but not finished, see: http://svnmios.midibox.org/filedetails.php?repname=svn.mios32&path=%2Ftrunk%2Fapps%2Fprocessing%2Fmidibox_cv_v2%2Fsrc%2Fcomponents%2FMbCvVoice.cpp

 

1st place: search for "transfer note -> linear frequency"

 

2nd place: search for "linear frequency -> CV frequency conversion"

 

It won't be so easy to finalize this, if you would like to work on the implementation, step forward. :)

 

Best Regards, Thorsten.

[chriss]

Hi guys. After some rather long baby and buchla absence I am starting slowly to collect info about my midi2cv module. Some nice progress here the last month. Has anyone build a box with a CS PCB with led rings and oleds? One question occurred yesterday when I wanted to check out the clock divider function. But I couldn't find it in the lemur template. Since I am not able to test this with the real core (and the minimal CS) at the moment, I wanted to ask if this will be implemented in the lemur CS. Or when it's already there where to find it. As you might know one of my most wanted wishes is to integrate the midi2cv into modular land. Clock input is already on the request list. Another one would be cc implementation. Then one could control the module with a cv2cc interface. (Clock speed, clock divide...... Can this be done? Does it make sense? Christoph.

[Imp]

Did you see there are analog ins on the request list?

 

support for up to 8 fast scanned analog inputs at J5A and J5B which can be used in the modulation matrix for modulation operations

 

If Clock speed and divide can be controled via mod-matrix, this should do the trick, or would a cv2cc interface have any additional benefits?

[TK.]

yes, the clock divider is still not implemented (and DIN sync input isn't implemented as well)

 

Will be something for my winter vacation, where I (traditionally ;-) work on MBCV

 

CC: all parameters are already available via NRPN, which is some kind of extended CC

Is this sufficient?

 

Best Regards, Thorsten.