[sdiy] Alesis Midiverb eprom images

[m.bareille at free.fr]

ooops sorry for the mistake in previous email ...

The eprom is a 27C256 !

Cheers,

Marc B.


Selon grant at musictechnologiesgroup.com:

> Judging from the photos I think you are correct. Pin 27 is A14 and it's
> pulled up to Vcc using the resistor you see. The switch probably just
> grounds A14 in one position and leaves it to be pulled high to Vcc by
> the resistor in the other position. This seems to indicate that the code
> is 27128 size or smaller, but they just used 27256's for cost or
> convenience.  So basically you have two "pages" (or banks) of 128kbits
> or 32kbytes.
>
> GB
>
>
> > -------- Original Message --------
> > Subject: Re: [sdiy] Alesis Midiverb eprom images
> > From: Tony Kalomiris <ic1 at bell.net>
> > Date: Mon, November 01, 2010 6:19 am
> > To: Robin Whittle <rw at firstpr.com.au>
> > Cc: synth diy <synth-diy at dropmix.xs4all.nl>
> >
> >
> > Morning Robin and list memebers,
> >
> > Ok I re-read your message, and think I understand now.
> > The MIDIVERB and MIDIFEX units only use one half of the 27C256 eprom.
> > That's why I got one half unprogammed for the first 16 K (not 256 as
> originally reported) - all FF's.
> > Ok the programs start at $4000.
> > The MVERBREV image is from the MIDIVERB and the MVERBFEX is from the MIDFEX
> unit, I'm guessing.
> > So  I would need to load these into a 27C256 and toggle the high order
> address bit, not a 27C512.
> > Sound about right ?
> >
> > Tony Kalomiris
> >
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