LPT to MIDI interface (first build, v.1.0.0.0)

Design Concepts
1

Hi there,

i needed to receive MIDI over LPT (parallel) port, but cant find any DIY solutions on the net.

So, I decided to do it myself. After one month of research, i has finally built first version of LPT2MIDI.

Here is a link: http://h4x0rz.ath.cx/plog/lpt2midi/

I hope, it will help to someone. =)

2

Interesting :slight_smile:

I didnt know that it is possible to connect via LPT…

many thnx for your work :slight_smile:

3

Plog------- You Rock!!! :smiley:

I’m on it. Always wanted to find something like that. I’ll try to check it out soon. I’ve still got a couple 16f84’s hanging around here.

Much Thanks!

George

4

Jidis,

just make sure that you have 16f84A, or others which can run on 20Mhz :] the 4Mhz is too slow :slight_smile:

please report me about your work in future :]

5

Hey again,

Yes, they’re definitely “A” chips.

I’ll let you know how it goes. :slight_smile:

George

PS- There are probably a few archived posts here from me looking for DIY parallel MIDI circuits over the years. It’s really surprising that there weren’t any out there.

6

I didnt know that it is possible to connect via LPT…

I have an Opcode patchbay providing 8 ins and outs through the parallel port, and it has a lot of standalone features, it’s impressive, considering it’s 100% made of easy to find parts (software is on ROM chips :wink: ).

7

Awesome! I hope we can continue our conversation about this in the chat sometime soon :slight_smile:

8

Plog, welcome aboard. Nice entry! :wink: Thank you very much. I dont find use of it right now but Im sure I think of something when I build it.

Why you needed the MIDI over LPT?

9

Well, i wanted to connect my midi controller to my laptop :slight_smile:

PCMCIA sound cards doesn’t have a game port, so the only way was to buy a midi interface.

But why to buy then you can do it yourself=)

I made it over LPT because my laptop doesn’t have any other ports :slight_smile:

Im planning to rewrite firmwire to support midi in & midi out in one PIC16F84A, or try to make more midi in’s.

The current firmwire source isnt optimized very well, and i have idea how to make it faster =)

In future i’ll try to port driver to win98/me, acctually i tried it but unsucessfuly =) programming and testing on separated PCs is confusing.

10

what about putting a parallel FIFO memory to the LPT ? And a DAC ?  ;D

11

I have an Opcode patchbay providing 8 ins and outs through the parallel port

Yes, but does it actually cooperate in 2008?? ;D

I’ve got a nice MOTU parallel box that I don’t trust for crap here due to its flaky 2K/XP drivers and a small MIDIMan 1x1 which does serial over one of those 25 pin ports (stuck at 98SE). Also an Opcode 2x6 rack box which is old Mac serial.

If Plog’s driver and circuit do OK, it might be cool to share some board swap designs for some of those old boxes. I redid the board for that 1x1 MIDIMan Portman box a while back, to switch over to a 9-pin serial connector, and still have the layout and hole diagrams:

BTW- That had PICs in it too. I think it was three 16C54 chips. The box itself is solid as a rock though, all steel and feels like you could run over it with a car without killing it.

George

PS Plog- That 98 driver would be great too. I’ve run some decent 98 machines which didn’t do well with audio & USB activity. 

Port.jpg
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12

Yes, but does it actually cooperate in 2008?? Grin

It works well with Windows 9x, but someone took the time to make XP drivers for it (not free however) so there are no compatibility problems (except you need a parallel port).

13

but someone took the time to make XP drivers for it

Man, that’s cool as s***. I’m surprised I hadn’t heard about that. Which Opcode box is it, the 128? I wish more of those parallel port manufacturers had done that, but maybe it makes a difference whether the company is dead yet. I wonder if they worked with Opcode on it.

George

14

It’s the Opcode MusicQuest 8Port SE.

Drivers here:

http://8portse.earthvegaconnection.com/index.html

It’s quite common on eBay for about $40-$80

http://www.harmony-central.com/Events/WNAMM96/Other/midi-solution.html

As I said, it would probably be easy to clone it as it uses commonly available parts (if it ever becomes hard to find, for example).

I’m surprised I hadn’t heard about that.

The interface isn’t that well known. Opcode was bought by Gibson and dropped a few years after, an invididual made the driver.

15

Quick post:

  1. We’re working on a opcode/motu style multi port design concept. Don’t ask: it’s likely to be vapor for a while, it’s not a trivial task.

  2. For those who don’t seem to know this already, LPT-driven MIDI has the best timing, and USB has the worst. LPT good.

16

If Plog’s around–

I started throwing together a layout for that tonight (because I hate breadboard ;D).

I’m guessing all those LED symbol things are just standard signal diodes, like the 4148 or something? Also guessing the MIDI i/o requires the same supplemental parts like in Thorsten’s core circuits here (the opto,resistors,etc.)?

Thanks Again,

George

17

Here’s another use for a parallel port: drum trigger sequencer

18

Jidis,

yes its the simple led diodes=) on RB7 - indicates error,  led near 8bit_register,  indicates NOT ENABLED (means that if on, then device is OFF, and 8bit register is in high impedance state, the all 8 bit data leds, show value comming from LPT port, so dont be scare then you see randomly lighted leds =)

about midi i/o you are right :slight_smile: but im just  using common ground between converter and my midi ctrl  without any optos & resistors.

you do not need a resistor on MIDI IN, cause its open collector (RA4 is input pin),

you don’t need a resistor on MIDI OUT too, cause its pin is from LPT control port, which means that they are already with 4.7kohm pull-up resistors :slight_smile:

if you made some PCB’s you may share it with us =)

19

Thanks Plog,

So they actually are LEDs. I just couldn’t figure why there were so many. I guess I should have skimmed over the whole batch of files (the asm) before asking. :-[

I’ll probably leave the MIDI i/o parts off this circuit and just put a couple pads or something to connect to, so I can change the stuff on the outside for right now.

Im planning to rewrite firmwire to support midi in & midi out in one PIC16F84A

Didn’t quite understand that part either. So, what exactly does it do for now if hit by simultaneous i/o traffic?

Thanks!

George

PS (if Stryd’s here) - So are you talking about another parallel port design? :o

20

for now the MIDI OUT is coming directly from LPT pin :slight_smile: (look at circuit)