25 Feb
2012
25 Feb
'12
11:24 a.m.
On 2/24/2012 1:23 PM, Tony Duell wrote:
A lot of the Eprom manufacturers had deals with various programmer
manufacturers. They
warranted that their eproms would program with those manufacturers, or
be replaced. There
was the desire not to have any one attempt programming their parts as
they really could not
tell when a bad version of a programmer destroyed their proms.
Sue.w That's one of the rasone often given, but I conisder it to be
somewhat bogus.
I've got other ways of making an EPROM go flaky, or die. Applying 240V (or
115V AC to the pins gernally kills them. So will a large enough static
zap. A lesser static zap will get them to fail some tim
The way to make sure I program in correctly is to publsih the programmign
algorithm. Then I will follow that,.
Having to use a commercial pgrogramemr of a particuler model is not
enough IMHO. Programmers can and do fail. If my programmed EPROMs stop
behaving coreectly how do I know if the programmer has fialed if I am not
sure what it's supposed to be doing? If I know the programming algorithm
I can put an logic analyser o nthe pins of the device being programemd
and see if it's being programmed correctly.
Wow, good
find! Must be a different (earlier?) edition of the databook
than the one I have.
I'ev heard the (IMHO mostly bogus) reasons for not
releasing such
information, and I can understand why it wouldn't be included in earlier
databooks and then included in later ones (either because many customers
are demandign it, or because they relaise there;'s no major risk in
releasing it), but I cna't see why it would be removed form alter
versions of the databook. Once the informatio nis out there, it's out
there...
-tony
We had a 2732 programmer which worked for a while, but then seemed to
start being flaky.
I looked at the waveforms of a blank eprom (and never programmed by our
programmer) in
a circuit, and saw nice clean waveforms for the accesses. After being
programmed, and
erased the waveforms stopped reaching the 0 level reliably. If I looked
at ones that were
programmed with other programmers no problem either.
Do you know waht the problem was? Too low a Vpp? Noise on the Vpp line
(or Vcc when programming)? Incorrect programmign pusle width?
In any case none of this would explain why a manufactuer would publish
the programming algorithm and then remove it from later versions of the
databook. If the algorithm is 'out there', somebody is going to find it
ans use it.
-tony