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From: hamilton@intersil.uucp
Newsgroups: comp.sys.amiga.hardware,comp.sys.amiga.audio
Subject: Re: Homemade MIDI interface
Message-ID: <254.2800a481@intersil.uucp>
Date: 8 Apr 91 17:12:32 GMT
References: <1991Apr6.064405.25982@sbcs.sunysb.edu>
Organization: Harris Semiconductor, Santa Clara CA
Lines: 24

In article <1991Apr6.064405.25982@sbcs.sunysb.edu>, ekarlin@csws5.ic.sunysb.edu (Erik S Karlin) writes:
>   I recently got the file midischem.lzh from ab20 and built the interface.
>   Other than not knowing whether the actual chips are bad (I doubt it) I have
>   checked and re-checked my work several times.
>   The problem is that I cannot get it to work.
>   I have a Casio CZ101 and tried MIDI in/out to MIDI in/out and
>   MIDI in/out to MIDI out/in  and still nothing.
>   The software that I have tried is: 
>   MED 2.3 , MED 3.0
>   CZEd, AlgoRhythms, MidiTools --from the fish disks
>   all did nothing.

I had a similar problem with my homemade MIDI interface (actually it's a 
MIDI OUT only-it's all I need right now and it's just a resistor hardware-
wise).  It wouldn't work with any of the software I tried, but it did work
whenever I'd probe it with my scope!  It turns out that the schematic I had
told you to connect the MIDI ground to shield ground (or something) rather
than system ground (or whatever it was).  When I moved the ground from one
pin to the next, it started working fine.  I'm sorry I don't remember
exactly what I did, but it was a while ago.  Anyway, it was ground-related.
-- 
Fred Hamilton                          "Unlike most of you, 
Harris Semiconductor                    I am not a nut..."
Santa Clara, CA                                            -Homer Simpson