I use Excel for such things because you can set the position very exactly
with cell widths and such.

-----Original Message-----
From: oberheim@yahoogroups.com [mailto: oberheim@yahoogroups.com ] On Behalf
Of Steve
Sent: Monday, January 17, 2011 4:44 PM
To: oberheim@yahoogroups.com
Subject: [oberheim] Re: The Perf/X units are all the same board! Cyclone,
Strummer, Drummer plz read!





I have a Drummer, and tried the cyclone rom in it. What fun!

To give a little back, I've uploaded the rom image from my drummer, as I
noticed it wasn't there. I also uploaded a zip file with a Cyclone front
panel image suitable for printing out and attaching to your Perf/X when the
cyclone rom is in it.

I created the front panel in raw postscript, as I couldn't think of an
adequate tool to do a bunch of "place exactly THIS text at exactly THIS size
at exactly THIS place on the paper" operations. I didn't work really hard at
following document structuring conventions, so whether this file is valid
postscript for whatever tool you might use is questionable. As not everyone
has access to a postscript printer, I also included a .pdf file and zipped
them together. (The pdf was created by viewing the postscript file on a Mac
with the Preview application, then saving a pdf. Hopefully that will be a
valid PDF for everyone.)

I also got together with my friend who has the EPROM programmer, and we
combined the Drummer and Cyclone images (each 32K) into one 64K rom, and put
a switch on the high order address line. We used a push on / push off
switch, and we placed it so that you can reach the switch through the unused
card slot on the side of the case. So now I can switch personalities without
opening the unit up, although it still requires clearing the battery backed
RAM.

This is getting long, but if I don't write it now, I'll probably forget by
the time someone asks me: I considered putting a 32K RAM chip in to try to
make each image use a different 8K, so I wouldn't need to clear RAM when
switching personalities. I don't think a 64K ram exists with a similar
pinout, so having 32K for each personality isn't an option for a single
chip. But the images are already designed to look for 8K or 32K RAM, and one
of the address lines for 32K goes into a CE line on the 8K chip, so there
are portions of the 32K address space where the 8K chip won't respond --
it's not just "shadowed" over the whole 32k region. I even investigated by
disassembling one of the roms a bit, and the result is I believe you need
additional circuitry to make sure your new ram won't respond at addresses
where an 8K RAM wouldn't, or the firmware will believe you have a 32K RAM
and probably overwrite parts of itself. My friend suggested the additional
circuitry could be a 7400 or a one-of-7 decoder, but I opted not to continue
down that path as time was short.

Also of note: space between the board and the front panel is minimal. The
alternative trick of stacking two chips in the place of one won't fit, at
least if you don't remove the socket (which may or may not work, I don't
know). That applies to ROM as well as RAM. In fact, my original ROM had its
pins trimmed, I assume so it fit lower in the socket; the remaining pins
wouldn't reach the eprom programmer for reading, we had to stick another
socket in between to make it work.

Anyway, thanks to all for pointing out this was possible and providing the
cyclone image!

--> Steve Wahl