[GUIDE] Direct MIDI IO for ST and Amiga Cores

[djhardrich]

Happy 808 Day, everyone!!

Got a quick writeup/binaries that'll be of interest to all of the musicians out there!

MickGyver edited the MiSTery and Minimig cores to support MIDI via the USER IO port, which makes a gigantic difference with MIDI timing/latency/jitter, and is super easy to wire up! We need a hero like Sorgelig (I know he's super busy with ao486, and I'm patient ) to help integrate this into main with a menu toggle that disables MIDILink if UserIO MIDI is enabled, but in the meantime, I'll attach a writeup in Markdown with images/binaries/links to source so everyone else can get in on the fun! I've been testing this for the past few weeks on a daily basis with the ST core, and it's completely stable. NOTE: Use 3.3v MIDI shields/boards -ONLY-! If the writeup is useful, please feel free to add it to the wiki/edit it once it's in main


Sources:

https://github.com/MickGyver/AtariST_MiSTer

https://github.com/MickGyver/Minimig-AGA_MiSTer

Have fun, and make some music!!!

[SmokeMonster]

Great work, this would be one of my #1 features if it could be cleanly implemented. Direct MIDI support to interface with real hardware and/or MUNT emulators on external devices is very cool.

[brunosilva]

why dont you make PR in official repos?

[djhardrich]

Bruno: I haven’t made a PR because the changes necessary to bring it into main are a bit more complicated than a pull/merge. I wasn’t sure if that would be the thing to do considering menu toggles need to be implemented/it needs to not interfere with MIDILink. I also know Sorg is very busy with ao486, so I didn’t want to add more by creating a PR when he can’t just pull it. I also don’t own the modified repo, so I don’t think I can actually create the PR?

[yavimaya]

It worked with direct pin to gpio on mt32-pi with atari st core
Could you share also ao486 source with support MIDI via the USER IO port to test?

Thanks!

[djhardrich]

yavimaya:
ao486 is slightly trickier and is being investigated (mpu401/non standard baud rate are involved), mind sharing details for wiring direct pin to gpio on pi? I know some people will find it useful (I’d actually like to know as well)!

[bbond007]

In the latest commits to ao486 Sorgelig now switched the UART speed to 31250 - MIDI speed. That should help simplify things for direct IO MIDI.

Is there any way to demonstrate the "timing/latency/jitter" with the USB MIDI adapters? I just have not experienced this myself.

[MickGyver]

It worked with direct pin to gpio on mt32-pi with atari st core
Could you share also ao486 source with support MIDI via the USER IO port to test?

Thanks!

Thanks to the correct MIDI baudrate now also for the ao486, I made a test version with IO MIDI for the ao486 core. The sources can be found here:

https://github.com/MickGyver/ao486_MiSTer

A compiled rbf is attached for anybody willing to test. djhardrich has done some testing already and he said it is working.

[djhardrich]

Thanks again, MickGyver!!

For ao486 set uart to midi in core settings, use mpu401 @ 330 in your dos apps, tested with Impulse Tracker, Doom

[djhardrich]

Here's the latest (20200818 release) Atari ST core with the User IO MIDI modifications made! Tested and working!

[Televicious]

Saw the doc in the last folder with the IO wiring. I see the MiST MIDI board or pi hat are being used. interesting. Any wiring diagrams for attaching to the USB header to plug it in? I can't find the pinout for user io. Oh NM, read the .md use a usb 2.0 not 3.0 That makes it much easier, now to find a USB to hack up. lol. Thanks!

[legacypixels]

Oooh, can't wait to test this with a little something I've been tinkering with....

midi_small.png (127.12 KiB) Viewed 48014 times

[NightShadowPT]

Oooh, can't wait to test this with a little something I've been tinkering with....

midi_small.png

What exactly is this?

[legacypixels]

Plug into MiSTer I/O board User port, other end into your MIDI device.
Tested and working with my Roland MT-32

[JimBobMcGee]

How hard would it be to produce these Mister MIDI IO boards? I am dying to get my hands on one so I can A/B test it with my 1040stfm MIDI Performance. I have always favored the Atari ST for music production purposes, especially driving external MIDI equipment.

[Televicious]

I would just get an olimex and hack a usb cable unless you live in or near Poland. I was going to get another mist midi board from lotharek so I don't cannibalize my mist, but shipping from poland is 45 bucks added on. That black pcb looks pretty cool though. Can't wait to test out midi maze between mister and mist. That and start making tunes again with mister.

[djhardrich]

Correct; both legacypixels and MickGyver are making ready-made solutions, this is so more people can use the cores now/hopefully the changes can end up in main soon, but wire one up (or ask legacypixels to sell you an early one if you’re in the States or Mick if Europe is closer)!

[legacypixels]

I still need to test the MIDI In port. Once I verify that I will have boards (with printed cases) ready to go.

[Higgy]

Anyone have an Atari disk or a demo on the HD image doing the rounds try out MIDI?
I have my PI-MIDI hat for MT32-PI and it is working well and I would like to hear this Atari MIDI
Thanks

[legacypixels]

I still need to test the MIDI In port. Once I verify that I will have boards (with printed cases) ready to go.

Initial Board testing completed:
MIDI IN and OUT working properly in Cubase 3 and Music Studio 88
Setup:
- M-Audio Keystation on MIDI IN
- Roland MT-32 on MIDI OUT
- MickGyver's Atari ST Core variant (20200808)
- Cubase 3 and Music Studio 88

Now Available at www.legacypixels.com

[bnz99]

This is awesome. Just a beginners question: I've ordered the Olimex board to tinker with the Atari ST midi. What is a good way to do the wiring? From what I understand, I don't really need the SNAC board as I don't need to 5V power. Can I essentially just use a standard usb3 cable, snip one end off and solder/plug the cables to the Olimex?

Edit:
Something like this, right?

mister-userport-olimex-midi-shield-cable.jpg (804.72 KiB) Viewed 47722 times

* Red to Olimex 3.3V
* Black to Olimex GND
* White to Olimex RX
* Green to Olimex TX

The legacypixel board looks great as well. Is there a reason why you made it separate from the Mister stack? I think it would be kind of cool to have it below the usb board in a special printed case or so.

[legacypixels]

The legacypixel board looks great as well. Is there a reason why you made it separate from the Mister stack? I think it would be kind of cool to have it below the usb board in a special printed case or so.

So, I envision it being used as a dongle kind of thing.
Adding it to the stack... The board is less than 1/2 the size of the de10, and it would add a lot of height- MIDI jacks are fairly tall.

Working on a couple small videos showing cubase and midimaze (with a 'real' ST)
Here's a pic with my MT-32...

mistermidi03.png (701.54 KiB) Viewed 47667 times

[bnz99]

Hey legacypixels, yes, the board would have a lot of unused space. Maybe it can be combined with a SNAC USB/HDMI adapter on the same PCB using a switch or so to justify the board size of the stack (and improve the use)

Anyway, I'm looking forward to see your videos, this midi stuff for Mister is fantastic and I can't wait to play around with it once I have all the necessary parts in my hands.

[JimBobMcGee]

The legacypixel board looks great as well. Is there a reason why you made it separate from the Mister stack? I think it would be kind of cool to have it below the usb board in a special printed case or so.

So, I envision it being used as a dongle kind of thing.
Adding it to the stack... The board is less than 1/2 the size of the de10, and it would add a lot of height- MIDI jacks are fairly tall.

Working on a couple small videos showing cubase and midimaze (with a 'real' ST)
Here's a pic with my MT-32...

mistermidi03.png

Legacypixels,

I got your PM, but am not able to use PM's until i have a few more posts. I am still interested in doing beta testing on the device.

[JimBobMcGee]

Testing the Olimex MIDI device, I am still not seeing any USER I/O option for the latest (20200808) core.

[JimBobMcGee]

Got it working. There is no need to enable the USER I/O in the UART menu. It just works! Works amazing so far! Will get results for the Olimex MIDI IO here.

[bnz99]

Amazing, this is incredibly cool. Thanks to everyone who worked on this. My Olimex board works as well. I have just recorded Midi into Cubase. My soldered cable posted above works perfectly. I think, I'm picking up a perfboard next and start to solder something that I can stack below my USB hub with a proper USB to USB connector instead of that temporary soldered cable.

I'm a little puzzled by the Olimex pin placement though. It doesn't even fit on a bread board as the pins don't have the correct spacing on one side.

[JimBobMcGee]

This thing immediately replaced my STfm from all MIDI duties. STEriods makes this thing a dream to work with in User MIDI I/O. Will be posting more video featuring my ASR10 as the focal point.

[ransom]

I am testing this new core on a mister mister with 32mb ram.

Using space quest enhance mt32 whdload slave with the sound driver automatically set to mt32..

When I run the game I get no sound? Does this work on its own or you need additional hardware for mister?

[bnz99]

I haven't tested the Amiga core, but I recall that there is a midi preference pane in Workbench where you can enable serial midi. Have you tried that?