Jump to content

Advice on where to start with midibox


Reggie
 Share

Recommended Posts

Hi all, I found this forum last night while searching for information on usb-midi for an stm32F4-Discovery board, it appears that someone awesome (TK I think?) has started a port to the stm32F4-discovery boards :-)

 

I understand that midibox isn't really just one thing, it appears to be a collection of things from synths and sequencers to controllers and manglers, I've just built myself a simple midi controller using an arduino mega1280 that's using serial and a serial to midi bridge, however, I have some teensy 2.0 boards on their way which will give me straight usb-midi, this will be entirely adequate for some smaller controllers that I want to build but midibox seems like an interesting path to wander down too :-)

 

I'd like to build a better controller with the stm32F4-Discovery board if that's possible, I mainly want to be able to design a sensible controller with the usual controls, buttons, sliders, pots, rotary encoders, I appreciate that at this time the stm32F4-disco support is limited to digital only so the pots/sliders will have to wait for analog support to be written.

 

I would also like to be able to manipulate the messages to a tempo when I hit certain buttons,so essentially providing midi controller based effects.  For instance, I might want to press a controller button and have it repeat every 8th note etc.

 

Bearing all that in mind, can any of you knowledgeable people suggest where I might start?

 

Reggie.

Link to comment
Share on other sites

Hey there and welcome :)

 

Best way to start - go to ucapps.de and choose a project you like. Most of them are based on the LPC1769 (not the STM32F4) uC though, but that is also a fine controller. Whenever you´ve found a project, there is plenty of documentation on ucapps.de and helpful people here in this forum :-)

 

Enjoy and have a great time!

Peter

Link to comment
Share on other sites

Thanks Hawkeye, I had a look at a lot of projects and they seem to contain a lot of dead links :-(  As you can appreciate, midibox is no small thing, I don't really fully understand all of the concepts yet, perhaps I need to start with that?

 

I understand that I need a core, which would be my stm32F4-discovery board.  I also see that there are other modules such as AIN etc. which seem to be units (another mcu?) that are attached to the core?  Which is where my understanding breaks down, with the stm32F4 board, I can't see me actually needing any extra add-on modules, the board should cope with everything already in it's own right, is that possible?

 

To start with I really just need to be able to use digital pins connected to buttons/rotary encoders to send note on/off and cc data via USB, perhaps something like 16-20 buttons, 8 encoders.  I'd like to be able to offline edit the button/encoder messages, in the future I'd like to add multiple messages per button (which shouldn't be difficult at all).  If I have to add external modules I have various atmega chips that that can send midi data over serial if necessary.

 

Is it worth trying to message TK at all, to see what the state of play is with his code or whether he can give me any pointers as he ultimately knows more than anyone on the subject?

Link to comment
Share on other sites

Hi Reggie,

 

I didn´t follow the developement of the stm32f4 discovery closely, but I don´t think it is quite ready yet to be integrated into the midibox hardware platform and probably won´t be until some time next year. So If you want to start now and don´t want to wait a year, you could focus on the current LPC17 core. As far as I see it, every idea you have about your controller can be easily realised by the available technology right now.

 

I suggest you have a look into the MB_NG firmware here, which is the most flexibel and powerful one right now.

 

Also have a look at all the available hardware modules. I think you misunderstood the concept behind them. First you need a core module (like the LPC17) that is able to run the MIOS32 system and the firmware you like. If you want to use hardware elements like buttons/encoders/leds/.... you have to connect all that to the core via another hardware module, the core itself doesn´t provide (many) pins for direct connections and neither will the new stm32f4 core.

So you need additional modules for your control surface elements:

 

encoders, buttons    ----> DIN module

faders, pots              ----> AIN or AINSER module

motorfader               ----> MF_NG module

leds                          ----> DOUT module

etc........

 

Have fun!

 

my regards

Link to comment
Share on other sites

To start with I really just need to be able to use digital pins connected to buttons/rotary encoders to send note on/off and cc data via USB, perhaps something like 16-20 buttons, 8 encoders.  I'd like to be able to offline edit the button/encoder messages, in the future I'd like to add multiple messages per button (which shouldn't be difficult at all).  If I have to add external modules I have various atmega chips that that can send midi data over serial if necessary.

 

John E Finster is right - just get and assemble a LPC17 module and one DINx4 module and read these fantastic tutorials: http://ucapps.de/mios32_c.html (#10 would be of interest). Then you can build about everything. Don´t rely on the STM32F4 support just yet.

 

If you are interested in a finished project that allows to be used as a MIDI controller, head to the MIDIbox NG section on ucapps.de - it is a very powerful unit that allows for a lot more and implements a scripting language to control it.

 

Many greets,

Peter

Link to comment
Share on other sites

Hi John, thanks for the reply, that's not what I was hoping to hear.  Especially considering the 100 exposed pins on the stm32F4-Discovery board.  Whilst I appreciate that not all of those pins will be available (there are 10 or so that are for 3/5v, vdd and ground) I had expected there to be access to quite a few of them.

 

To start off with I just need be able to use it as a general controller sending midi via usb, it feels like complete overkill right now to start mashing other ICs together when the disco board has everything onboard already.  Then again, just using it as a controller with a ton of buttons seems underkill :D

 

It's a shame as I'd hoped the modules were software style plugins, setup the number of pins, which pins you want to use, add functions to go with them and away you go.

 

Reggie.

Link to comment
Share on other sites

I've already got quite a few boards and chips here, just not an lpc1769.  However, the entry price of an lpc1769 is very cheap, I'm not sure I'd even need a din socket, if midibox talks serial and i2c/spi then i can possible use those interfaces.  I've got shift registers, 8bit atmega chips so I have lots of options.  I've got some other boards coming that will give me most of what I want immediately, the controller box I've already built is just throwing out midi via serial 5v, once those projects are out of the way, I can then think about an lpc based board to hook these other units into.

Link to comment
Share on other sites

Hi all, so I've decided that an lpc1769 would be the way forwards but it will have to wait until I get some more money.  In the meantime, I found a midi usb firmware for the arduino leonardo which is the same atmega32u2 as a little breakout board that I've got, which gets me where I want to be with simple usb to midi commands and my current controller.  it gives me options for experiments while I wait for an lpc board.

 

I also managed to harvest some 4051 chips, they're soic but I have some tssop-28 breakouts that can take the chips if you're very careful about MISplacing the chip, the 4 corner pins all connect to a single pad, the other 12 connect to 2 pads, it should be ok.

 

there's also a handy little breakout for the lpc board too, lots of pads for different smt stuff, very useful I think.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
 Share

×
×
  • Create New...