[sdiy] digitally switching cv and audio lines

[ASSI]

[sorry for the late reply, I'm swamped with work...]

On Wednesday 26 February 2003 23:55, Ken Stone wrote:
> no news is good news?  Silence means consent? Seriosly, even a simple
> graphic would help. There is no way I am downloading eagle just to
> look at a single board design.
On Thursday 27 February 2003 20:25, Yves Usson wrote:
> Well, I found the description of your project very promising
> however, I don't use Eagle therefore I can't read your project files.
> Would you make these available in another format (GIF or PDF) ?

I should be able to export the schematics and board to PDF and link 
that for viewing/download on the weekend. However my quick first 
attempt was less than satisfactory and I have to dive into the 
parameters for the print function to make it a worthwhile download. Try 
my homepage again on Sunday, I should have it sorted by then.

On Friday 28 February 2003 00:34, Tom Arnold wrote:
> The chip looks intriguing.  Its alot cheaper then others I have
> looked at. The board layout, while clean, I think could use some work
> just from a Use point of view.  I suppose if you were putting this
> into a self contained unit it'd be great, but I'd probably go with a
> single connector of some kind for that application, and as part of a
> large patchbay, I'd go with a much larger circuit board so I could
> land connectors directly on the board.

The board layout is a direct function of the limitations that the 
freeware version of Eagle imposes (half-Eurocard format and two layers 
only). Ideally I'd want to do a four layer board to minimize crosstalk 
and use a slightly larger board with less/different connectors. No can 
do with this version of the software, even though I think I could hack 
two extra supply-only planes with scripts (I'm not sure this would 
still be within the license). However if you think of this board as a 
building block, this not too bad especially considering diy constraints 
on testing/reliability/availability. My idea currently is to use 
different input and output boards connected by ribbon cable depending 
on what I want to use the matrix for. One might go for direct board 
connection through posts, in this case you can actually condense the 
layout a bit.

Note that the other board layout demo packages I tried disqualified 
themselves early because they either had ridiculous limits on the 
number of pins or packages or didn't allow me to create a new library 
part for the AD75019.

Thanks for the comments so far. While putting the files together I 
refined some ideas and I'm now thinking more seriously about actually 
building the audio patchbay I originally planned with an additional 
twist - I want to have fixed lines from the matrix into my mixer so 
that I can route these freely between all the sources and sinks, and 
the rest of the lines go to a normalized patch panel. I guess I can 
even steal the power from the mixer...

I'm still unsure about the control processor (MIDI, a few pushbuttons, 
LED/display perhaps). Lot's of folks seem to use PICs, but I tend to 
like the AVR specs better (pricewise it looks like a draw). Then there 
is the Z8 (something I've actually used years ago) and HC11/12 - quite 
confusing. I have currently no idea about the relative merits of the 
development systems and wether free toolchains are even available, 
preferrably running on Linux (Z8 should be there, dunno about the 
rest). Thinking ahead a bit I'd probably like to get a FORTH system up 
and running on one these. Bonus points if one of the family members can 
grow a USB or (gawd!) Ethernet port. Any comments on these (I guess 
directly to me is nicer to the list - I can summarize later) would be 
appreciated.


Achim.
-- +<[ Q+ & Matrix-12 & WAVE#46 & microQkb Omega sonic heaven ]>+ --

Q MIDI Implementation:
http://homepages.compuserve.de/Stromeko/Qstuff/QSysEx_preview.pdf