Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!caen!ox.com!math.fu-berlin.de!uniol!Frank2.Simon From: Frank2.Simon@arbi.informatik.uni-oldenburg.de (Frank 'Biber' Simon) Newsgroups: comp.music Subject: Re: RS-232 to MIDI Message-ID: Date: 14 May 91 13:30:37 GMT References: <2679@fornax.UUCP> Organization: University of Oldenburg, Germany Lines: 44 troy@fornax.UUCP (Troy Brooks) writes: >I'm trying to find an RS-232 to MIDI interface to connect to the >.. >(MPU - 401 ?) don't use RS-232 because the baud rate is too slow on >PCs. (9600 baud). So, if I can't find one, I'll have to build one, >... It isn't possible to build a RS-232 to MIDI-Interface, because the baud rate is too slow (it's up to 19 200 Baud). The only way is to specify the RS-232-Interface. The only different between RS-232 Interface and MIDI is the very high baud rate (31.250 Baud) and the optical split to disconnect the Keyboard of the Computer. So there are only two things to do: 1) A new Quartz to get the 31.250 Baud 2) Optodisconnectors to make two circuits. To 1) In the RS-232 Interface there is a UART 8250 doing his job. He has got some frequency-divider in it. 31.250 Baud is for example to get with a quartz of 4 Mhz and a divide rate of 128 (because 4 M/128=31250). To 2) In the MIDI-Specifikation is written to use Optodisconnectors. Because of the high baud-rate you can't take every one, but there are some working with this rate. In the german journal C't (computer-Technik) of Januar this Year there's written a articel to build a MIDI-Interface of a RS-232. The C't suggest to build a luxury MIDI-Interface which can be switched (via software) between MIDI and RS-232 mode). The electric-parts you need aren't very expensive. It isn't also hard to build this Interface. For more details mail me -- FRONT242FRONT242FRONT242FRONT242FRONT242FRONT242FRONT242FRONT242FRONT242FRONT E-MAIL-ADDRESS: ~ I am ~ MAIL-ADRESS: Frank2.Simon@arbi. ~ because ~ Frank Simon informatik.uni- ~ somebody ~ Alexanderstr. 156 oldenburg.de ~ dreams me ~ 2900 Oldenburg