prindle@NADC.ARPA (Frank Prindle) (07/27/89)
I have a schematic for a MIDI interface which I will post if there is suffic- ient interest. There are basically 3 MIDI interface standards for the C-64 worldwide. Here in the U.S., the two most widely used are the Sequential Circuits standard and the Passport standard. The third standard is known as the Siel/JMS(Jellinghaus) standard and is common in Great Britian and Europe. The particular schematic I have is for the latter (European) standard based on the MIDI cartridge offered by Datel. If I do post it (which requires that I render it into ASCII form), I'll suggest modifications to the circuit to make it Sequential and/or Passport compatible. Basically, in their Dumb/UART mode, all these interfaces work the same - the differences are only in the port addresses and clock frequencies (I'd be glad to elaborate if there is interest). Each interface also has it's unique "smart" features which make it incompatible with any other (e.g. on board clocks, analog tape/drum sync ports, foot switch port, etc.); the most compatible software will not rely on any of these features to work properly, and will be configurable for one of the 3 basic standards. As far as software is concerned, I own the Sonus package Glass-Tracks (a MIDI sequencer) and several other public domain and home brew programs which work with MIDI interfaces. One of these is Craig Chamberlain's MIDIPLAYER which plays any (mono) SID song through your choice of MIDI polyphonic or polytimbral keyboard or sound module (compatible with all 3 standards). Another program I am currently working on samples a MIDI keyboard while you play whatever you want (6-note polyphonic), optionally plays through the C64's SID chip and a second SID chip mapped to $DF00, and generates a sequence file which a second program turns directly into a stereo Sidplayer file pair (it really takes at least 6 voices to fully realize the functionality of polyphony with just about any piano piece; POLYDEMO is nice for scales, but who plays scales?). As far as building a MIDI interface, I shouldn't think it too hard for someone with experience in building prototype cards. One cheap 6850 UART, a crystal, and a hand full of 74LS type gate chips will do it. The hardest part is getting/making a board to fit the 44-pin expansion slot edge connector. I've found a proto-board at Radio Shack that can be cut down to do the job, though I'm fond of printed circuits, but find doing dual sided boards by hand a bit impossible. Sometimes long hours with a soldering iron or wire wrap tool are the only solution. Card mounted DIN sockets are hard to find too, so you might have to settle for panel mount types. I think that amateur MIDI dabbling is one area where the C-64 still has a lot going for it. All the expensive Amiga/Mac/IBM MIDI hardware and software is a lot of overkill for non-professional musicians and the 64 fills the void nicely once you overcome the basic hurdles. Sincerely, Frank Prindle Prindle@NADC.arpa
scott@max.acs.washington.edu (07/28/89)
In article <POSTNEWS10852@NADC.ARPA>, prindle@NADC.ARPA (Frank Prindle) writes: > I have a schematic for a MIDI interface which I will post if there is suffic- > ient interest. Could you please post the schematics for the MIDI? I will be very interested in seeing the schmatics, and I am sure there are alot other people who wants to see it too....... Thanks.
prindle@NADC.ARPA (Frank Prindle) (07/29/89)
The project published in Commodore Magazine some months back was hopelessly incompatible with any software written for standard interfaces since it does not allow the UART to be directly addressed, but ties it to one of the CIA ports. As I recall, it was a MIDI-OUT only interface - i.e. it did not have the required optoisolator and associated UART interrupt capability to allow the 64 to capture incoming MIDI data streams as well as generate outgoing MIDI. The interface plans I will post soon will be of a more traditional and complete design. Sincerely, Frank Prindle Prindle@NADC.arpa
wilso_d@cs.odu.edu (DeWitte Wilson) (07/30/89)
Frank, go ahead and post the schematics for the MIDI card, its about
time I dove back into building my own equipment. Am I to understand that
once built, most of the PD software packages will talk to it?
...dewitte
--
DeWitte Wilson <wilso_d@cs.odu.edu> Old Dominion University
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