[sdiy-interim] EPROM Armageddon?

[Plutoniq9]

Is there any reason to use EPROM's anymore? I use flash memory in DIP 
packages, they are drop in replacments for standard 27c256's.......I can 
erase, burn and verify in around 15 seconds (65,536-bytes).

Cya

Ryan


>
>Actually, there are "simple" (cough) equations for calculating *minimum* 
>EPROM storage times. It is based on the temperature, the gate oxide 
>thickness, the initial MOSFET channel capacitance, the doping level and a 
>few more factors. 20yrs is "standard" and probably 25yrs typical. But a LOT 
>of synths that use EPROMs are approaching 25yrs (even the DX-7!).
>
>As far as I know, the smallest new EPROM is a 27C256 (ST makes them).
>
>Not to be alarmist, but it's not too unreasonable to assume 75% of all 
>analog poly synths AND drum machines will be unable to operate over the 
>next 8 years or so.
>
>If the EPROMs don't cause a failure, then the capacitors probably will :)
>
>Paul S.
>
>
>
>
>
>
>
>
>
>On Wed Mar 28 11:27 , Robin Whittle sent:
>
>
>
>
>The Jupiter 8 has a Z80 CPU and three or four separate 2716 EPROMs.
>
>Address lines 2 and 3 are swapped over on the PCB, so it is best to read
>
>the chip with those pins swapped if you want to see the data as the CPU
>
>does. However, for copying the chips, just use an ordinary EPROM
>
>programmer.
>
>
>
>How EPROMs or Flash memory chips hold the charge in their little silicon
>
>islands is something of a wonder, but there is no fixed lifetime for the
>
>charge draining away or the chip failing in other ways. If they are
>
>still holding data in a hundred years, or a thousand, it would not be
>
>entirely surprising. It is a good idea to keep copies of the chips, or
>
>make sure someone has a copy. In my experience the data rarely, if
>
>ever, fades away.
>
>
>
>I have a big old Benson plotter, the size of a piano - like this one:
>
>
>
>http://www.chilton-computing.org.uk/gallery/ral82/med/r82r3197m.jpg
>
>
>
>The driver software came in Fortran source code on a reel of 1/2"
>
>magnetic tape. In the heart of its digital servo system (optical
>
>encoders and DC motors with 0.001" precision) there is a 1702 EPROM:
>
>
>
>http://www.computermuseum.li/Testpage/Chip-Intel1702EPROM.htm
>
>
>
>I keep telling myself I should read the data from this, a triple supply
>
>voltage device which ordinary programmers can't read, in case the data
>
>fades away one day. This was the earliest EPROM, and it was probably
>
>programmed about 30 years ago.
>
>
>
>- Robin
>
>
>
>http://www.firstpr.com.au/rwi/dfish/
>
>
>
>
>
>keith sterling wrote:
>
>
>
> > I had a terrific conversation with Paul Schrieber of MOTM the other
>
> > day, during which he mentioned that my beloved Jupiter 8 was destined
>
> > for the landfill soon because it contains CPU embedded EPROMS, and
>
> > all EPROMS have an implied 20 year (or thereabouts) lifespan. Since
>
> > the Jupiter's ROM is inside the CPU chip it can't easily be read and
>
> > reprogrammed in a new chip, like one could do with a discrete 2716
>
> > type EPROM.
>
>
>
>
>
>_____________________________________________________________________
>
>This is the interim list for synth-diy at dropmix.xs4all.nl.
>
>To post, synth-diy at vermine.org
>
>To unsubscribe, http://vermine.org/cgi-bin/mailman/listinfo/synth-diy
>
>
>
>
>
>---- Msg sent via Internet America Webmail - 
>http://www.internetamerica.com/
>


>_____________________________________________________________________
>This is the interim list for synth-diy at dropmix.xs4all.nl.
>To post, synth-diy at vermine.org
>To unsubscribe, http://vermine.org/cgi-bin/mailman/listinfo/synth-diy

_________________________________________________________________
Mortgage refinance is hot 1) Rates near 30-yr lows 2) Good credit get 
intro-rate 4.625%* 
https://www2.nextag.com/goto.jsp?product=100000035&url=%2fst.jsp&tm=y&search=mortgage_text_links_88_h2a5f&s=4056&p=5117&disc=y&vers=743


_____________________________________________________________________
This is the interim list for synth-diy at dropmix.xs4all.nl.
To post, synth-diy at vermine.org
To unsubscribe, http://vermine.org/cgi-bin/mailman/listinfo/synth-diy