[A83] Re: Flash protection

To: assembly-83@lists.ticalc.org
Subject: [A83] Re: Flash protection
From: Peter-Martijn Kuipers <hyper@hysoft-automation.com>
Date: Mon, 23 Jul 2001 09:30:46 +0200 (CEST)
In-Reply-To: <000501c112c3$784e3ac0$3742530c@kingkong> from "Michael Vincent" at Jul 22, 2001 08:31:52 AM
Reply-To: assembly-83@lists.ticalc.org


To me it seems like you need to exchange the values of OE# and WE# in order to
write.

Logic Low seems to be "true", while Locig High seems to be "false".

While it is said that CE# and OE# *must* be Low to read data (which you still 
want to do, right :-), it only says that WE# *should* be High to read data.

What you could do is hardwire WE# to Low, while still being able to reverse 
your changes, and see if you can still read from the device.
If so, the only thing you need to deal with is setting OE# to High...
Maybe TI hasn't protected that option so severely, thus making it possible to
write to some port to set it low. 

--(Peter-Martijn)
 
> Thanks, but I've already looked in the manual for it. It's confusing. I have
> it uploaded at www.radicalsoft.org/michael/hardware/83p/flash.pdf if anyone
> wants to take a look and try to decipher it.
> 
> 
> Michael Vincent
> Detached Solutions - www.detacheds.com
> Radical Software - www.radicalsoft.org
> 
> ----- Original Message -----
> From: "Peter-Martijn Kuipers" <hyper@hysoft-automation.com>
> To: <assembly-83@lists.ticalc.org>
> Sent: Saturday, July 21, 2001 11:34 PM
> Subject: [A83] Re: Flash protection
> 
> 
> >
> > Hmm, you might want to look up the manual for the flash chip.
> > If you  type it's serial number in a search engine, it will hsow up
> somewhere.
> > (It's the AMD chip, but you knew that already)
> >
> > --(Peter-Martijn)
> >
> > P.S.
> >
> > If it works, you might want to post a "That's how I did it" on the list.
> >
> >
> > >
> > > I have a spare 83+ lying around, and I have been wanting to bypass the
> flash protection. I understand that there is a pin (WE I think) on the flash
> chip which is locking the flash from writes. Can anyone tell me which pin
> this is on the actual chip, and how to bypass it? Thank you.
> > >
> > >
> > > Michael Vincent
> > > Detached Solutions - www.detacheds.com
> > > Radical Software - www.radicalsoft.org
> > >
> > >
> > >
> >
> >
> >
> 
> 
>

References:

[A83] Re: Flash protection

From: "Michael Vincent" <hookman@worldnet.att.net>