MIDI Interface

Dale King, 1994
dwking@indyvax.iupui.edu
c23dwk@kocrsv01.delcoelect.com

Quelle: Als File im Internet abgelegt unter mac-to-midi-interface.hqx

Das Midi Interface

This is an update to the self-powered Macintosh MIDI interface schematic I previously released. Changes are: changed 480 ohm resistors to 470 (since there are no 480 ohm resistors) and changed 2K pull-up to 680 ohms to improve rise time characteristics (thanks to Lars Lindqvist).

This is a binhexed version of the schematic I have created for a Macintosh to MIDI interface that derives it's power solely from the serial port (No external power is necessary). It is configured for 1 MIDI In, 1 MIDI Out, and 2 switchable MIDI OUT/THRU's. You can configure the outputs as Outs, Thrus, or switchable Out/Thru. There is 1 gate not being used which can be used to add an additional output if desired.

The only problem with powering it from the serial port is when you just want to use the MIDI Thru without necessarily using the Mac sequencing S/W. The TXD lines on the Mac are only powered when a program has opened the serial driver. So even if you have the Mac turned on you will have to load either your sequencing software or a terminal program. The only part of the interface that is of any use without sequencing software is the MIDI thru, so most of the time you want to use the interface, you`ll have sequencing software loaded anyway.

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