10 Apr
2002
10 Apr
'02
3:54 p.m.
Rumor has it that Fred Cisin (XenoSoft) may have mentioned these words:
On Wed, 10 Apr 2002, Christopher Smith wrote:
> At one point I considered making an "illustrative project" of building
> a pseudo fuse blown PROM out of several inline type fuses -- like are used
> in power supplies, for instance.
> It would be possible to illustrate not only electronically, but visually,
> the way that the ROM works. :) "The black ones are 0s... ;)" (or is that
> a 1?)
AFAICT, burned fuses should be a logic 0... but I've never worked with
anything less than LSI/MSI, so...
> Anything beyond a size of several bytes would be
unmanageable, of course.
> I figured you might fit 64 bytes in the size of a VHS tape if you use
> small fuses.
Maybe more with picofuses, but they'd be hard to change [see below]
Since the it is for illustration, rather than for
significant real usage,
16 bits should be plenty to show how it works.
Glass fuses don't blacken unless you really whack them with a lot of
current, and can sometimes be very hard to even see visually whether they
are blown.
Ceramic fuses, such as what VW used to use would be the easiest to
visually check which ones are blown, but it's hard to find them in smaller
sizes than 8 amps.
Would you be programming in place, or "cheating" and assembly the unit
with fuses that are already blown?
If you actually put sockets on the board and insert the fuses into that,
you could simulate an EPROM/Flash[like] part. ;-) It'd take a while to
"erase & re-write", but hey... ;-)
Just my $0.000000000002 [CDN], and it ain't worth that!
Roger "Merch" Merchberger
--
Roger "Merch" Merchberger --- sysadmin, Iceberg Computers
Recycling is good, right??? Ok, so I'll recycle an old .sig.
If at first you don't succeed, nuclear warhead
disarmament should *not* be your first career choice.