All set guys, it was the link cable, thanks for the help!

That diagram did the trick.

Yeah If I were you I'd make dang sure your cable matches the provided pinout. Use a multimeter to test each pin.

No, it's the pre-built kitch x Xiwi, I just got it the other day.

My cable was built by a friend, I trust him, but I think I might take a look just to make sure.

The xiwi is a kit, right? Has it previously worked and then stopped? I've never used a xiwi kit but I've messed around a bunch with them and the only time I've seen it lock up is if the link cable is incorrectly wired or if some of the arduino pins aren't connected correctly.

Yeah I've tried that, no good. AB locks up, gameboy acts just fine, but still no midi out or led flashes.

Have you tried setting sync mode to MIDI out in LSDJ and on the Arduinoboy before connecting the cable to the link port?
I have also got crashes and hanging, but I solved it by doing things in this order.

Both haha. As far as I can tell lsdj is functioning as it should, it's the arduino that's having trouble.

I'm basically in the same spot as Timbob.

Master sync works, but when I try to set everything midi out I get the exact same issues he shows above, my lsdj doesn't crash that hard though, it just locks up until I unplug it from the AB. Hardware wise everything should be cool, I've tried different gameboys and the AB is a brand new kitsch x Xiwi.

Which issue, the freezing thing or just no midi out of LSDJ?

I'm having this exact same problem with my Xiwi Arduinoboy! Any luck?

Sooo, I got another arduino. rebuild the whole thing.

It doesn't make lsdj crash anymore. but it won't let me send midi notes either.

what I did is... I replaced: The arduino, the gameboy, the cables, all components, the lsdj cart...

I don't know what to replace anymore now.
why won't it send midi notes? It does a master sync with no problem.
this is confusing.

If you socket the Arduino than you can easily switch it out in the future, some seem to have problems after a while.

I tried it on different gameboys, and they all give the same crashes
So I borrowed another arduino, and I'm gonna build a new one. To see if that one works.. I don't know what can be the problem anymore.

check the gameboy itself, if there is a loose bit of metal or solder shorting the pins in the link port then it can lock the arduinoboy.

So, I rebuild the whole thing. (well, almost whole. no midi in yet)

And the troubles keep appearing.
I connected the colours like this photo i found of another arduinoboy: http://imgur.com/a/Qlm3R#GcagD
Also checked for breaks and right connections, it should all check out this way.

The same troubles keep crashing and burning.

Midi master sync works fine.
arduinoboy won't let me cycle modes, it stops at the midi out mode. (unless i press the button while booting)
If the arduinoboy is in midi-out mode, the gameboy completely glitches up when I try to change sync mode (even from off to slave.. any change crashes), But it will let me change modes when it's in, say, master sync.

I tried different gameboys, different EMS carts. reflashed the arduino and the carts..
I'm kind of at a loss here..
Is my arduino broken? and why does it only crash with midi-out?

Oh, the only thing that's different on my arduinoboy is that pin 3, with the button, uses a 2k2 resistor instead of a 2k, I couldn't find any. But it worked with that resistor a year ago just fine..

I just switched to a DMG-07 cable after it was build semi-internally. but it didn't work correct on both cables/connections.
I checked the cable for breaks, but it seemed fine.

So, I just reassembled the whole thing, And I'm gonna build it again

I only forgot to write down the cable colour / connection.. Are those DMG07 all coloured the same? and if so, is there a list with colour to connection?