[sdiy] 3.3V and MIDI

[Paul Maddox]

Bert.

  Peter makes a good point, it *should* be fine as long as you get the
current right.
I'd be interested to hear how you get on, I would doubt that any of the
modern DSP based synths would use 5v for Midi, as they would have to add
another regulator to the PCB (more parts,more cost), so I would guess many
of them do it this way.

Paul


----- Original Message -----
From: "Ullrich Peter" <peter.ullrich at kapsch.net>
To: "Bert Schiettecatte" <bert.schiettecatte at esat.kuleuven.ac.be>;
<synth-diy at dropmix.xs4all.nl>
Sent: Saturday, June 07, 2003 1:14 PM
Subject: AW: [sdiy] 3.3V and MIDI


> >I've just received my development kit for Cygnal's microcontrollers.
> >Of course I'd like to add a MIDI interface to it. Unfortunately the
> >development board is all 3.3V, no 5V available. Before I add a
> regulator,
> >I was wondering whether I can just get away with using 3.3V for
> >the midi interface? or does it really have to be 5V to comply with
> >the standard?
>
>
> As the MIDI interface is a current interface (nominal 5mA) it should be
> no problem as long as the current can be sinked on the MIDI outport. But
> you will have to adjust the resistor (normally 220 ohms) values so that
the
> current of 5mA can flow.
> Remember that the receiver also has a 220 ohm resistor on teh input.
>
> Ciao
> Peter
>
> Http://ullrich.at.tt
>
>
>