Casio CZ/ VZ/ FZ - Pro Series

Hi Scott,

I just got sent a photo of a ROM card opened up. There is not much 
difference with the RAM and ROM PCB, the RAM has more etchings and 
tracks in it for an extra chip that does switching of the CE (Chip 
Enable) pin, and also the WE (Write Enable) pin, both of which the 
ROM doesn't need. And a few other differences in the pin track 
layouts to the RAM chip, but that's it. I've uploaded a schematic for 
the RAM card in the FILES section on this site. 

Regarding having a larger chip, the schematics show already that it 
was made to accommodate a chip 2x as large as the one used, there is 
a spare address line not used on the connector. This is for the ROM 
chip, which is 2x larger than the RAM chip (which is why it has an 
extra bank of sounds) - The ROM is 512k and the RAM is 256k. It would 
require no more effort than dropping in a 512k RAM chip and hooking 
up the extra address line. As you say, an even larger chip can be 
installed and the highest address lines switched with a DIP switch to 
get extra banks.

Cheers, Graham



--- In CZsynth@yahoogroups.com, "Scott Nordlund" <gsn10@...> wrote:
>
> It would be easy to make a larger capacity card: just get a bigger 
RAM chip 
> (1 Mbit would give you 4 banks), and use DIP switches or something 
for the 
> additional address lines.  Or, multiple chips could be stacked and 
switched 
> using the CS line.  It just depends on what chips are available.  I 
think 
> the only hard part would be finding a suitable connector.
> 
> Do you have a schematic for the ROM cards?  I think it would be 
possible (if 
> not particularly pretty) to use a ROM card as a starting point 
(making 
> changes to account for the difference in the way ROM/RAM cards are 
> detected).  If the ROM chip has a CS line, it would probably be 
pretty 
> simple to add a switch to choose either ROM sounds or RAM sounds.
> 
> 
> >From: "gmeredith1" <gmeredith1@...>
> >Reply-To: CZsynth@yahoogroups.com
> >To: CZsynth@yahoogroups.com
> >Subject: [CZsynth] Make your own Casio VZ/PG RAM card!!
> >Date: Fri, 01 Jun 2007 02:17:00 -0000
> >
> >Hi Everybody!
> >
> >I've managed to get hold of the schematics for the very rare RA500 
RAM
> >card, used in the Casio VZ1/10M/8M and the Casio PG guitar synths,
> >thanks to Steve at the EZ-VZ forum website. It will now be 
possible to
> >make one of these RAM cards yourself for about $20!!
> >
> >I'm in the process of making up a step-by-step guide with photos, 
which
> >I will upload to the FILES section here when I've finished them. 
In the
> >meantime, for anyone who's good with electronics, I've uploaded the
> >RA500 card schematics there, along with datasheets and other info, 
so
> >you can start straight away!!
> >
> >Cheers, Graham
> >
> >
> 
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