dan@rna.UUCP (Dan Ts'o) (11/18/85)
x Where can I find out the hardware and sofware definitions of MIDI ? What are the electrical characteristics of MIDI, the protocols/command and data formats used ? I have seen various articles stating the baud rate of MIDI to be either 31500 or 31250 - which is it ? 31250 is easier to generate. I also understand that it is current loop, is it identical to the old 20ma current loop ? I also hear that MIDI requires opto-isolation. Would it be reasonable to convert an old DEC serial interface, DL-11 or DLV-11, to MIDI ? They both have external clock inputs and can both be set for 20ma current loop. What would be required ? How do these PC's hack a 31.25Khz interrupt rate (maybe they do polled I/O) ? Would writing a patch librarian from scratch be completely ridiculous (it doesn't seem too hard...) Thanks. Cheers, Dan Ts'o Dept. Neurobiology Rockefeller Univ. 1230 York Ave. NY, NY 10021 212-570-7671 ...cmcl2!rna!dan rna!dan@cmcl2.arpa
hedger@ada-uts.UUCP (11/21/85)
Dan, First of all I am in the process of writing a patch librarian for a Rhodes Chroma to run on a c-64. Getting the MIDI spec itself isn't too difficult(see below) but the most important thing is obtaining information from the manufacturer of the synth about their 'system exclusive' MIDI information. There are two ways that I know of to obtain a copy of the MIDI spec. 1) Join or find someone who is a member of IMA (International Midi Association) For (I believe) a $40.00 annual membership fee they will furnish you with the current MIDI spec, a newsletter, and I think MIDI specs for instruments produced by member manufacturers. 2) Keyboard magazine has published a series of books which are basically reprints of Keyboard articles. One of these (Sythesizers and computers), contains a copy of the MIDI rev 1.0 spec in the appendix. It also has articles that were interesting to me, but I have a very basic knowledge of computer hardware, so some of the articles might seem pretty mundane to a person with a lot of experience in this area. keith hedger ihnp4!inmet!ada-uts!hedger
spallett@andromeda.UUCP (Carl Spalletta) (11/27/85)
> Where can I find out the hardware and sofware definitions of MIDI ? > What are the electrical characteristics of MIDI, the protocols/command and > data formats used ? In the book 'Synthesizers & computers' published by Keyboard magazine you can find a copy of the MIDI spec (which is in the public domain) I bought mine at Sam Ash Music .. The hardware specification is one page long, plus a circuit diagram consisting of exactly one IC, one diode, six resistors , plus buffering. > I have seen various articles stating the baud rate of MIDI to be > either 31500 or 31250 - which is it ? 31250 is easier to generate. I also > understand that it is current loop, is it identical to the old 20ma current > loop ? I also hear that MIDI requires opto-isolation. '31.25 KB' > Would it be reasonable to convert an old DEC serial interface, DL-11 or > DLV-11, to MIDI ? They both have external clock inputs and can both be set fo> > 20ma current loop. What would be required ? I would be interested in talking to you about this, because I dont know the answer myself, but I suspect you would do better starting from scratch because MIDI is so crude and so peculiar. I'm interested in doing an interface for the PC myself, now putting together the block diagrams and bill of mat'ls. Anyone out there with any suggestions or any experience in implementing MIDI?