Midi-interface For Gp2x

[firestARTer]

I just added my first version of the new Midi-Interface for GP2x.
It works at the moment with LittleGpTracker but it's also simply possible to optimize other software to use it.
At the moment only Midi-Out is supported, but Midi-In will be added aswell.

Info: http://www.firestarter-music.de/gp2x/

greetings
firestARTer

http://www.firestarter-music.de
http://www.myspace.com/firestartermusic

 

[kevcal]

excellent!
Could this be used with Outcast (Atari ST emulator) software...??

EDIT:
Mmmm looking into it more, implies a recompile of Outcast to redirect midi-comms I guess..
Thought years ago I saw a simpler serial to midi-out circuit with a few discrete components in an atari mag;
but of course midi is 31250bps and we can I guess only get 38400bps - maybe my memory's not what it was

EDIT2:
Could the clock divider in the kernel's serial driver be modified to get close to the desired baudrate I wonder?
I know nothing of the built-in UART - apart from it's apparently 4 channel?

 

[firestARTer]

My Interface is actually converting 38400 to 31250 baud.
So if you can get outcast to talk with the serial port, it is possible to use it!

excellent!
Could this be used with Outcast (Atari ST emulator) software...??

EDIT:
Mmmm looking into it more, implies a recompile of Outcast to redirect midi-comms I guess..
Thought years ago I saw a simpler serial to midi-out circuit with a few discrete components in an atari mag;
but of course midi is 31250bps and we can I guess only get 38400bps - maybe my memory's not what it was

EDIT2:
Could the clock divider in the kernel's serial driver be modified to get close to the desired baudrate I wonder?
I know nothing of the built-in UART - apart from it's apparently 4 channel?

 

[kevcal]

Doesn't sound like a huge change (for someone who knows what they're doing); I have a copy of pro24 on the st - where do I plug the dongle though Clab'sNotator wouldn't be too good - needed a 'hires' monitor for that (640x400 I think).

I'm just looking at the magic eyes manual to see how configurable the uarts are with respect to baudrate... that would mean just a serial driver software mod... I guess a long shot though.
Although there does appear to be a PLL divisor for each uart - ie URTnCLKDIV which can be set from 1 to 64... I guess the source for the kernel serial driver is available - would be interested to see how baudrates are setup - I may of course be going off at a tangent here
Also I shouldn't be looking into this as your interface does all we need at that end of it

 

[herr_prof]

there are so many cool midi apps on the atarist... this could be HUGE

 

[starpause]

Doesn't sound like a huge change (for someone who knows what they're doing)
I'm just looking at the magic eyes manual to see how configurable the uarts are with respect to baudrate... that would mean just a serial driver software mod... Also I shouldn't be looking into this as your interface does all we need at that end of it

31250 to 38400 is a huge change ... it's a difference of 7150 bits per second. if the sending equipment and the receiving equipment don't agree on a baud rate, the data frames won't line up and the receiving end gets garbage.

the gp2x hardware can do any baud rate you want, but linux will only allow you to set the port to baud rates that are powers of 900 (an artifact from cheep serial ports common on PC computers). if the linux kernel was updated to allow you to set any baud rate, the gp2x could send and recieve 31250 bits per second and be compatible with all midi gear.

the open2x project is addressing this issue and craigix said gamepark would put that feature on the list for firmware 3.0, whenever that's coming. when it happens, you'll still need to build a serial<->midi cable.

since firestarter's cable works now, and is compatible with piggy tracker, i've got to build one

on that note, i did up a lgpt.man.txt (based on the lgpt wiki), compatible with the latest gMenu!

 

[kevcal]

you'll still need to build a serial<->midi cable.

I realise that - albeit a much simpler one
This would be great - pity my synth is gathering dust (for the last <eek> 20 years) and I have moved on to guitar...
Now if we could find a cheap and easy method to get sound input to the gp2x and port effects unit software over... yet another use for the little black box.
Anyway this is great news for sequencer junkies.

 

[torpor]

This is a great hack, but there's a far easier way to add MIDI to the GP2X and it doesn't require any soldering irons: USB-MIDI interfaces, plus MidiShare.

I've done a port of MidiShare to the GP2X, which I hope to release soon, and it rocks hard .. great to have a kernel-integrated module that can provide superlative USB-MIDI driver support.

Anyway, good stuff on the hacking front .. indeed the GP2X offers a great potential for MIDI enthusiasts ..

 

[firestARTer]

Of course this would be a easier solution! The only reason i started with my midi-box is, that there was nothing available yet and i needed one

Maybe i get a point for the price, since i don't need alot of components

This is a great hack, but there's a far easier way to add MIDI to the GP2X and it doesn't require any soldering irons: USB-MIDI interfaces, plus MidiShare.

I've done a port of MidiShare to the GP2X, which I hope to release soon, and it rocks hard .. great to have a kernel-integrated module that can provide superlative USB-MIDI driver support.

Anyway, good stuff on the hacking front .. indeed the GP2X offers a great potential for MIDI enthusiasts ..

 

[torpor]

Hey nobody is complaining that you've got a working solution out there, no sir!

It'll be great to see what you do with MidiShare when its out ..

 

[kevcal]

Yeah, sorry - wasn't complaining about this - it's great!
Just me being a software bod, I always look for a software solution

 

[moxie]

This is madness, in an excellent way!

I was going to say "as mad as those blokes with the music soft on cart for the C64", but the I realised that you're involved with those blokes as well

This will be built!

 

[firestARTer]

No complaining from me either

Looking forward for your midishare port aswell!!

Hey nobody is complaining that you've got a working solution out there, no sir!

It'll be great to see what you do with MidiShare when its out ..

 

[rooster]

linux will only allow you to set the port to baud rates that are powers of 900

powers of 900?

I think i'm gonna have to double-check your BPM calculations on this forthcoming drum machine