Midi, serial ports, uart's and the compaq aero

[Rene Schmitz]

At 16:43 09.10.98 +0100, you wrote:

>I've dowloaded your files - they look very useful, and nice and simple for a
>single cv/gate output, but my cv convertor is processor based, and has 40 cv
>outputs and 32 gate outputs.
Ahh, thats what I've dreamed of, when I made my (very basic) convertor.
I intend to add more outputs by adding s&h stages which are selected by 
other lines of the centronics port. So I can make all the programming in C
on my
PC)

>What I want to do is just to cut out the serial midi interface from the PC
>to my cv convertor.
>I gave up using my PC for sequencing because the timing via my midi
>interfaces was dreadful - probably down to latency in the soundcard etc.
>more than just midi itself, but I found it unusable.
>If I can use a midi driver in seq303, Cubase etc, that speaks to my cv
>convertor processor directly, via the parallel interface, I may be able to
>start using my PC for sequencing again. 

A driver of that type like the mrouter or the Cv-Gate driver (which just
adds a "patch point" into the midi stream, it still routes) can cause
trouble when Applications try 
to use it as In and Output port simulataneously. Sort of digital feedback
loop...

Also, my friends use a cv convertor
>I built for them, and I had big problems getting two soundcard midi
>interfaces to work on their PC (they use one interface just for cv'ed gear).
>They would benefit from a parallel i/f to their convertor too.
>My convertor already has a printer port compatible interface that just
>expects to receive midi bytes directly - so it seems I just need to work out
>how to write the midi bytes to the parallel port on the PC and off I go...

The sources of the driver can give you some hints about how the bytes are
packed into 
the double words. Windows packs every single Midi instruction into a dword
with 
running status disabled, only the driver for the soundcard determines if
running status is used on the external hardware. But I've just figured out
about the basic messages how they are encoded. If I remember correctly the
bytes have a reversed order, the low word contains the info if 
it is a note or contoller message, and the high order has note and velocity
data.
Sysex is not handled like other messages, so mrouter (and my driver) can't
use it at all.

Bye
 -René 

PS. Me too! (I'd like to see a description of your CV convertor, too.;-)
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