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ivop

MIDI Interface

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Hi,

 

I have decided to build myself a MIDI Interface for the Atari XL/XE. Based upon an old schematic from Elektronika Praktyczna (6/98), I came up with this:

 

post-20947-0-19290700-1503496507.png

 

It's 5cm x 5cm and supports MIDI IN/OUT/THRU. The device is turned on/off by the Motor Control Line.

 

Now the question is, would anybody else be interested in this and, if so, what would you like? PCB only, PCB+parts, or fully build? (all excl. SIO cable)

Note that I have not build anything yet, although some parts are on their way.

 

Regards,

Ivo

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It depends on what Midi Track supports. As far as I can see there are two different types of interface. Some use an external crystal to clock Pokey at exactly 31250 (i.e. Midimate) and the others use a Pokey frequency which is close enough. All seem to use Motor Control to enable and disable the device and free the SIO bus again.

Edited by ivop

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Would be interested in bare board. A suggestion, add 3 pin header footprints under the DIN sockets to allow panel mounted sockets instead of board mounted DINs.

Yogi

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Hello Ivo

 

Wouldn't it be easier in use if all three DIN plugs would be on the same side? Or if somebody wants to build the interface into a larger case?

 

Sincerely

 

Mathy (who already has three MIDI interfaces, all MIDI-Mate compatible except for the missing sync ports. Fully MIDI-Mate/MIDI-Maze compatible)

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what software support this interface?

 

These should definitely work:

MIDIPlay v1.3 by Ireneusz Kuczek

MIDIRec v1.2 by Ireneusz Kuczek

MIDI PatternEditor MPE v.2.3 by Radek Sterba

MIDI Sequencer 1.15 by Maciej Sygit

 

Possibly more, I don't know. This is my first venture into the 8-bit MIDI world.

 

Wouldn't it be easier in use if all three DIN plugs would be on the same side? Or if somebody wants to build the interface into a larger case?

 

I decided on a 5x5 board mainly because of the price, but I also like the small form factor. Having IN and THRU at opposite sides reminds me of guitar stompboxes. The pin headers I just added as per Van's suggestion is meant for panel mounted DIN connectors and larger cases. But, nothing is set in stone yet. The PCB is pretty full at the moment, so I guess if any other features need to be added, I'll upgrade to 5x10cm.

 

Regards,

Ivo

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I would be interested in a couple of boards. Having a parts list would be of great help also.

 

I had downloaded some files from CompuServe and took a look at them a couple of months back. One of the files is:

 

 

MIDIDR.DOC (MIDIDR.XMO)
MIDIMate Software Interface Documentation 5/21/1985
By Hybrid Arts, Inc.

 

If you haven't seen it, the .atr holding this file and can be downloaded from this blog entry. There is also a MIDI handler that can be used with BASIC and should work with your interface. In case someone wants to program the next MidiMaze game.

 

http://atariage.com/forums/blog/572/entry-13705-a8-midi-and-the-atari-age-of-rediscovery/

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Yes, it's a SIO device. Dual Pokey should be no problem. It could actually be beneficial if one were to write a piece of software to use the Atari as a sound module. You lose channel 3+4 of the first for MIDI communication, but you could use channel 1+2 and the second pokey's channel 1+2 and 3+4 for three 16-bit audio channels in total.

 

Update: I'm going to order the PCBs tomorrow. I'll start with a batch of 10. More than enough components coming in the following weeks for 10 complete units.

 

@pack007, I checked the Fig-Forth code in your ATR and uses the external clock line, which this device does not support. I also glanced over the Midimaze ROM, and it does the same. But, I don't think it'll be too hard to "fix" them for this device. Perhaps somebody already did that "back in the day"?

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Yes, it's a SIO device. Dual Pokey should be no problem. It could actually be beneficial if one were to write a piece of software to use the Atari as a sound module. You lose channel 3+4 of the first for MIDI communication, but you could use channel 1+2 and the second pokey's channel 1+2 and 3+4 for three 16-bit audio channels in total.

 

Update: I'm going to order the PCBs tomorrow. I'll start with a batch of 10. More than enough components coming in the following weeks for 10 complete units.

 

@pack007, I checked the Fig-Forth code in your ATR and uses the external clock line, which this device does not support. I also glanced over the Midimaze ROM, and it does the same. But, I don't think it'll be too hard to "fix" them for this device. Perhaps somebody already did that "back in the day"?

I was also thinking this the other day about a dual Pokey set-up :)

Yogi

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All components and the PCBs (10 pieces) have been ordered. As for the price, probably somewhere between €10,= and €15,=. First I want to build one and verify its working before I take orders. But I have a ballpark estimate now as for the amount of interest there is. Thanks for that. I'll get back to you when I have built one successfully :)

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