Overview of OWL pin assignments

[dromer]

Hey, I finally got a chance to test the Axowl firmware and was able to flash one of my Axolotis from plugdata!

Now I'm wondering how I could create a device around this using the different gpio to parameter mappings.

cheers! o/

[antisvin]

That took a while, didn't it? ;-) What are you trying to use instead of Axocontrol?

Either way, the general is direction is like this:

1. Open Axoloti.ioc with CubeMX. Looks like I was using v6.3.0 at that time, you may have to tell it to migrate if newer version is used. Or try to use the same version to reduce unnecessary changes from CubeMX migration.
2. Edit your GPIO settings as necessary, make sure that you edit ADC settings accordingly
3. Export the project
4. Take a look at git diff output, there likely will be some things that you'll want to rollback (there are manual edits in current code, i.e. in main.c file and typically for USB stuff but likely much more than that)
5. Maybe edit hardware.h - depends how drastically you're going to change hardware
6. Edit Axolototi.cpp to match your hardware UI. Currently it's made for Axocontrol and I guess you'll have to throw a lot of it away

Of course you can make a copy of this project under a different name instead of editing in place.

[dromer]

Today I was primed when I saw someone selling some Axoloti boards and realized I still have an unused one. And since we now can program to OWL from plugdata I wanted to see if it could be done!

I'm not using anything for the hardware yet since I just have a bare Axoloti and was wondering if/how the GPIO can be mapped to OWL parameters :)

Ok, so this is a lot more work than I expected. So basically a completely new base firmware needs to be created in order to create new mappings?

[antisvin]

Yeah, OWL just delegates hardware configuration to CubeMX. And you can't override its hardware mapping dynamically.

If you don't have any specific analog board to use with it yet, maybe actually try making an AxoControl? It's open hardware and available knobs/buttons are adequate. Designing something similar in functionality but using different pins makes little sense to me.

The only thing that I missed with it would be an SPI display and an encoder. That brings huge usability improvements to any device. There are available pins for connecting something like that, but I didn't feel like it's worth the effort when the MCU is only STM32F4.

[dromer]

I didn't realize that OWL could address displays, but makes sense given Magus and Genius. I've only been using it via the Lich.

Arguable a Lich-like with segment display, rotary encoder and a whole lot more knobs and maybe LEDs would be nice.
But I guess for starters a diy Axo-Control with some spare parts is certainly doable. And otherwise stick to MIDI.

What are then the i/o that are exposed with the Axo-Control in mind?

[dromer]

Ah, I see the notes file: https://github.com/antisvin/OpenWare_Axowl/blob/axoloti/Axoloti/notes.txt#L3-L6

Params : A B C / D E F / G H (joy)
Buttons: 1 2 3 4 (4 = joy, pushbuton)

Patch selection L/R - single press, or press and select

[antisvin]

Yeah, there are LEDs on it that show button state IIRC, also I remember making an UI for showing patch number in binary using them.

Regarding Lich and displays: https://community.rebeltech.org/t/write-patches-in-rust/2238/12?u=antisvin

[dromer]

How does this Patch selection L/R work exactly?

[antisvin]

I think you might be able to do it without Axocontrol as it uses only those tiny S1/S2 switches on Axoloti core boared as input. IIRC, you would press them to enter configuration mode, then do as described in the docs: https://antisvin.github.io/OpenWareLab/Axoloti/#how-does-patch-selection-in-axowl-ui-work

It would be hard to understand what's going on as it uses LEDs for patch number for indication

[dromer]

Thanks, maybe one day we can mod it to use a segmented display like Lich ;)