silver@eniac.seas.upenn.edu (Andy Silverman) (10/04/89)
You should probably know that you can't use the 8250 to talk to MIDI easily. MIDI is a current loop, not RS-232 so without hardware modification you can't use standard serial ports to talk to MIDI. Also MIDI signals are opto-isolated from the UART, so grit your teeth and buy a MIDI controller from Roland or Voyetra. +-----------------------+-----------------------------------------+ | Andy Silverman | Internet: silver@eniac.seas.upenn.edu | | "All stressed out and | Compu$erve: 72261,531 | | nobody to choke." | | +-----------------------+-----------------------------------------+
peter@ficc.uu.net (Peter da Silva) (10/04/89)
In article <15046@netnews.upenn.edu>, silver@eniac.seas.upenn.edu (Andy Silverman) writes: > You should probably know that you can't use the 8250 to talk to MIDI easily. Yes, but. > MIDI is a current loop, not RS-232 so without hardware modification you > can't use standard serial ports to talk to MIDI. Also MIDI signals are > opto-isolated from the UART, There are many good reasons for buying a MIDI card, but electrical compatibility isn't one of them. Gadgets that convert RS232 levels to MIDI are available for the Amiga, and cost $50 or so. You get a midi in, midi out, and at least one midi thru. The big problem with doing MIDI from a regular IBM serial port would seem to be CPU. The machine just doesn't have the guts for it. Maybe with a smart serial card. And for your $$$ a real MIDI card would be better. -- Peter da Silva, *NIX support guy @ Ferranti International Controls Corporation. Biz: peter@ficc.uu.net, +1 713 274 5180. Fun: peter@sugar.hackercorp.com. `-_-' ``I feel that any [environment] with users in it is "adverse".'' 'U` -- Eric Peterson <lcc.eric@seas.ucla.edu>
bmarsh@cod.NOSC.MIL (William C. Marsh) (10/06/89)
In article <6403@ficc.uu.net> peter@ficc.uu.net (Peter da Silva) writes: >In article <15046@netnews.upenn.edu>, silver@eniac.seas.upenn.edu (Andy Silverman) writes: >> You should probably know that you can't use the 8250 to talk to MIDI easily. > >Yes, but. > >> MIDI is a current loop, not RS-232 so without hardware modification you > >There are many good reasons for buying a MIDI card, but electrical >compatibility isn't one of them. > >The big problem with doing MIDI from a regular IBM serial port would >seem to be CPU. The machine just doesn't have the guts for it. Maybe >with a smart serial card. And for your $$$ a real MIDI card would be >better. >-- Actually, the main problem with doing MIDI on the PC seems to be a lack of a 'good' timer, i.e., something with resolution better than 18.2 times per second. I have software which uses a really simple MIDI interface, which has just a serial port *and* another timer chip, and it can do quite reasonably, even on a non-turbo XT! A major (for me) reason for buying a Roland interface is because everyone and their brother writes software for that interface, and only one person (you ;-) will write software for the inexpensive interface. (BTW, I think there is a problem getting the baud rate correct for the MIDI interface with normal PC serial ports, as it is NOT 38,400, but 31,250.) Bill -------- Bill Marsh, Naval Ocean Systems Center, San Diego, CA {arpa,mil}net: bmarsh@cod.nosc.mil uucp: {ihnp4,akgua,decvax,dcdwest,ucbvax}!sdcsvax!nosc!bmarsh "If everything seems to be coming your way, you're probably in the wrong lane."
dregis@pldote.intel.com (~Dave Regis) (10/06/89)
> A major (for me) reason for buying a Roland interface is because everyone > and their brother writes software for that interface, and only one person > (you ;-) will write software for the inexpensive interface. Approximately how much does the Roland MIDI interface cost? I've got a Yamaha TX81Z, and my Mac/Midi set up is going to my sister and her family; I would like to hang on to my tone generator but see no reason to unless there is reasonably priced hardware and software for the PC. Dave Regis