MIDILPT

Discussion about old sound cards, MIDI devices and sound related accessories.

MIDILPT

Postby dreamblaster » 2018-5-06 @ 11:50

hi,

I started work on a new project : MIDILPT :

MIDI interface on parallel port.
The idea is to make it work with SOFTMPU.
I tried to design it with through hole components only,
so it could become an easy solder kit.
The result is pretty large : approx 55mm x 55mm

Would this make sense ?
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midilpt_top3d.png
midilpt_front.png
midilpt_back.png
midilpt_3d_view.png
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Re: MIDILPT

Postby keropi » 2018-5-06 @ 13:50

very nice!!!!
I can see it working on some retro-gaming laptops - now to create a *LPT base to have all the devices connected :blush:
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Re: MIDILPT

Postby M-HT » 2018-5-07 @ 10:03

Would it make sense to have place on the PCB for Waveblaster header ? To either use MIDI out or Waveblaster header in case you already have DreamBlaster S1,X1, S2 or X2.
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Re: MIDILPT

Postby Scali » 2018-5-07 @ 10:14

So, the device would basically have a parallel-to-serial interface? Basically just a UART? And SoftMPU will provide full MPU-401 compatibility? At least for midi-out.
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Re: MIDILPT

Postby dreamblaster » 2018-5-07 @ 16:01

Scali wrote:So, the device would basically have a parallel-to-serial interface? Basically just a UART? And SoftMPU will provide full MPU-401 compatibility? At least for midi-out.

yes, that's the idea
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Re: MIDILPT

Postby xjas » 2018-5-08 @ 07:33

YES. Will be following this with great interest. :)
selected (probably) unfinished build threads { In a Lunchbox / Has It All / Hot Damn! / IT IS THE NINETIES / 20 Years of Junk }
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Re: MIDILPT

Postby dreamblaster » 2018-5-13 @ 20:27

redesign, using attiny to make smaller pcb, better ergonomics,
dual 3.5mm MIDI OUT (it will use 3.5mm to DIN cables), reset button..
midilpt.png
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Re: MIDILPT

Postby xjas » 2018-5-13 @ 20:40

Looking good! Are those dual individual MIDI buses (i.e. 16 channels EACH) or do they just mirror each other? Being able to drive two independent multitimbral devices (i.e. a JV1010 and Yamaha XG module in my case) would be super useful.

MIDI IN would also be nice, even if it's just a pinheader on the PCB.

SoftMPU should cover DOS support well, but I'm thinking I might take a stab at writing a VXD driver for this thing (how hard could it be??) when it's further along in development. Any interest in that?
Last edited by xjas on 2018-5-13 @ 20:44, edited 1 time in total.
selected (probably) unfinished build threads { In a Lunchbox / Has It All / Hot Damn! / IT IS THE NINETIES / 20 Years of Junk }
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Re: MIDILPT

Postby Scali » 2018-5-13 @ 20:43

Looks very nice!
I think it may especially be useful for old 386+ laptops that you can't add midi to in any other way.
It's probably also going to be cheaper than an ISA card.
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Re: MIDILPT

Postby dreamblaster » 2018-5-13 @ 20:52

xjas wrote:Looking good! Are those dual individual MIDI buses (i.e. 16 channels EACH) or do they just mirror each other?

It is just mirrored, both outputs have exactly the same signal

xjas wrote:MIDI IN would also be nice, even if it's just a pinheader on the PCB.

hmm right now, only midi out

xjas wrote:SoftMPU should cover DOS support well, but I'm thinking I might take a stab at writing a VXD driver for this thing (how hard could it be??) when it's further along in development. Any interest in that?

That would be GREAT !
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Re: MIDILPT

Postby dreamblaster » 2018-5-13 @ 21:00

How about this feature ?
now that there's a CPU, considering to send 'all notes off' on bootup
--> this will allow to shutdown midi hanging notes by pressing reset.

Also will try to keep the interfacing compatible with S2P
--> same pinout, same drivers :-)
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Re: MIDILPT

Postby xjas » 2018-5-13 @ 21:09

The mirrored ports are still handy as it cuts down on the number of pass-throughs needed. If you could find a way to cram on a MIDI-IN, I can think of a bunch of applications it would be great for - using a '90s laptop as an OPL3 sound module for example, or sending a MIDI clock between two machines for sync.

dreamblaster wrote:How about this feature ?
now that there's a CPU, considering to send 'all notes off' on bootup
--> this will allow to shutdown midi hanging notes by pressing reset.


Yeah a kill switch is always handy, I haven't run into a hung note in my own setup in a while but it's nice to have a clean way to zap them.

dreamblaster wrote:Also will try to keep the interfacing compatible with S2P
--> same pinout, same drivers :-)


That would be sweet, that means I could essentially start with a Win9x port of the version of SoftMPU for S2P & support both devices. I found a VxD guide with some sample code online and it doesn't seem too complicated. I'm relatively new to Win9x coding though; will be a great way to expand my range. :)
selected (probably) unfinished build threads { In a Lunchbox / Has It All / Hot Damn! / IT IS THE NINETIES / 20 Years of Junk }
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Re: MIDILPT

Postby dreamblaster » 2018-5-13 @ 21:24

xjas wrote:That would be sweet, that means I could essentially start with a Win9x port of the version of SoftMPU for S2P & support both devices. I found a VxD guide with some sample code online and it doesn't seem too complicated. I'm relatively new to Win9x coding though; will be a great way to expand my range. :)

Yes ! I will PM you
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Re: MIDILPT

Postby dreamblaster » 2018-5-15 @ 19:04

MIDILPT PCB's ordered
to be continued when they arrive
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Re: MIDILPT

Postby matze79 » 2018-5-17 @ 05:08

Why do 2 modules ? :) just add a wavetable header
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Re: MIDILPT

Postby Super_Relay » 2018-5-17 @ 06:14

matze79 wrote:Why do 2 modules ? :) just add a wavetable header

the biggest problem you have with a wavetable header is that while the s2/x2 work on purely 5 volts most other wavetable cards require +12v and -12v which you can't source nearly so easily.

I made a daughter board to use the s1 with dosbox on a raspberry pi and if i wanted it to be able to use a yamaha DB50XG or even a smaller diamond wavetable card i would basically need to put an ATX power connector on it to get the voltages required to run them.
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Re: MIDILPT

Postby dreamblaster » 2018-5-22 @ 19:55

The PCB is ready and soldered ...
MIDILPT.jpg

(no coding yet)
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