ian@sq.uucp (Ian F. Darwin) (02/09/88)
As I wrote on the same subject while reviewing an EPROM programmer from a small American company (in MicroSystems, sometime in '83 or '84): I also found out (without harming the board) what happens when you put in the correct EPROM, but insert it upside down. *The little light inside comes on.* You didn't know there was a little light inside an EPROM, did you? Well, there wasn't supposed to be, and it's not there anymore anyway!
eric@hdr.UUCP (Eric J. Johnson) (02/15/88)
In article<1988Feb9.151701.6201@sq.uucp> ian@darwin.UUCP (Ian F. Darwin) writes:
As I wrote on the same subject while reviewing an EPROM programmer
from a small American company (in MicroSystems, sometime in '83 or '84):
I also found out (without harming the board) what happens when you
put in the correct EPROM, but insert it upside down.
*The little light inside comes on.*
You didn't know there was a little light inside an EPROM, did you?
Well, there wasn't supposed to be, and it's not there anymore anyway!
Here we call that a "one-shot LED" :-)
--
Eric J. Johnson UUCP: eric@hdr.UUCP || ...!{ihnp4, codas}!hdr!eric
Amperif Corporation. CIS: 72460,11 BIX: ericj
Crusher... Crusher? We don't need no Wesley Crusher!straka@ihlpf.ATT.COM (Straka) (02/18/88)
In article <194@hdr.UUCP> eric@hdr.UUCP (Eric J. Johnson) writes: >In article<1988Feb9.151701.6201@sq.uucp> ian@darwin.UUCP (Ian F. Darwin) writes: > As I wrote on the same subject while reviewing an EPROM programmer > from a small American company (in MicroSystems, sometime in '83 or '84): > > I also found out (without harming the board) what happens when you > put in the correct EPROM, but insert it upside down. > *The little light inside comes on.* > You didn't know there was a little light inside an EPROM, did you? > Well, there wasn't supposed to be, and it's not there anymore anyway! Reminds me of a little experience back at National in the old days: (Bear with me, the end of the story is kind of neat!) Before N-channel EPROMs there were P-channel EPROMS (eg. 1702, 5404(?)). These devices were real pigs. You see, you are really working against physics to get the electrons up to the floating gate. The only reason for P-channel at the time was because nobody was too good at making N-channel yet (contamination, threshold stability, ...). Anyway, you had to hit these little puppies with 55V to do the programming! At the wafer probe stage (real, virgin device), the technique was to start with a ~20V programming voltage, and repeatedly hit the chip with higher and higher voltages until the 55V was reached. If you hit it with 55V right away, you blow away the part. The thoery was that during this "puhout", as they called it, you actually heat up the local junctions enough to *modify the metallurgical junctions* in critical areas so that they could take the extra voltage without braeking down. One day, one of the product engineers for that product was talking to me, and said: "Come on over here by one of the wafer probers. I have something to show you." He was probing a virgin wafer, and during the "pushout" part of the test program, you could see (black cloth around the probe station microscope) a few of the traces on the chip faintly INCANDESCE from the immense current draw! It would only happen the very first time that the device was programmed. Just a little bit eerie. One wonders about long term reliability. -- Rich Straka ihnp4!ihlpf!straka Advice for the day: "MSDOS - just say no."
john@frog.UUCP (John Woods, Software) (02/19/88)
In article <194@hdr.UUCP>, eric@hdr.UUCP (Eric J. Johnson) writes: > In article<1988Feb9.151701.6201@sq.uucp> ian@darwin.UUCP (Ian F. Darwin) writes: > I also found out (without harming the board) what happens when you > put in the correct EPROM, but insert it upside down. > *The little light inside comes on.* > You didn't know there was a little light inside an EPROM, did you? > Well, there wasn't supposed to be, and it's not there anymore anyway! > > Here we call that a "one-shot LED" :-) > Ah, yes. A few years ago, I was helping to debug a sickly PDP-11/45. As we were poking around with the scope, one person asked "What does this LED on the CPU board mean?" Someone else replied, "There aren't any LED's on the CPU board...OH, SH*T!" -- John Woods, Charles River Data Systems, Framingham MA, (617) 626-1101 ...!decvax!frog!john, ...!mit-eddie!jfw, jfw@eddie.mit.edu "Cutting the space budget really restores my faith in humanity. It eliminates dreams, goals, and ideals and lets us get straight to the business of hate, debauchery, and self-annihilation." -- Johnny Hart
farren@gethen.UUCP (Michael J. Farren) (02/21/88)
>> I also found out (without harming the board) what happens when you >> put in the correct EPROM, but insert it upside down. >> *The little light inside comes on.* >> You didn't know there was a little light inside an EPROM, did you? >> Well, there wasn't supposed to be, and it's not there anymore anyway! One of my favorite stories (I've got a million of 'em) from the olden days was when I was sitting at the good ol' Intel development system, programming a 2708 with the latest and greatest. An assembler happened to be standing there, and said "Wow! Those things get real hot when they're programmed, don't they?" I looked up, and sure enough, the EPROM was red-hot and backwards. Pulled it, and programmed another, but later, out of curiosity, tried the "red-hot" one again. Programmed perfectly, and worked just fine from that point on. I was impressed (but not enough to use it in a production unit!) -- Michael J. Farren | "INVESTIGATE your point of view, don't just {ucbvax, uunet, hoptoad}! | dogmatize it! Reflect on it and re-evaluate unisoft!gethen!farren | it. You may want to change your mind someday." gethen!farren@lll-winken.llnl.gov ----- Tom Reingold, from alt.flame
marki@tahoe.unr.edu (Mark N. Iverson) (02/28/88)
In article <3741@ihlpf.ATT.COM> straka@ihlpf.UUCP (55223-Straka,R.J.) writes: > >... Reminds me of a little experience back at National in the old days: >(Bear with me, the end of the story is kind of neat!) ^^^^ I think KINKY is more like it! %^) > ... I have something to >show you." He was probing a virgin wafer, and during the "pushout" part ... > > ...Just a little bit eerie. One wonders about long term reliability. I thought condoms could only be used once! :-) :-) >Rich Straka ihnp4!ihlpf!straka > Sorry, just couldn't pass that up.