Hijacked Terminology?

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I noticed the DS2502 datasheet says:

 

1k-Bit EPROM with Page-Level Write Protection and Guaranteed Unique 64-Bit ROM ID Chip for Absolute Traceability.

 

However, I didn't see any means to erase it, so assume they meant PROM (user Programmable Read Only Memory), 

as opposed to EPROM (user Erasable Programmable Read Only Memory)

 

but then further along I see:

1024 Bits Electrically Programmable Read Only Memory (EPROM)   WHAT!!!! 

 

Don't forget  EEPROM (user Electrically Erasable Programmable Read Only Memory)

 

Is this twisted EPROM terminology a new "thing"? What happened to PROM?  Maybe some preschoolers started some kind of protest?

I'm burning two proms tonight...what! call the police!

 

https://datasheets.maximintegrated.com/en/ds/DS2502.pdf

 

 

edit clarified:

Is this EPROM a new thing?

TO:

Is this twisted EPROM terminology a new "thing"?

When in the dark remember-the future looks brighter than ever.   I look forward to being able to predict the future!

Last Edited: Fri. Jun 26, 2020 - 04:52 AM
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Is this EPROM a new thing?

No that's the Erasable version. You expose the quartz window to UV to erase. With the newer chips (without the window) you need to drill a suitable hole on top instead..........

John Samperi

Ampertronics Pty. Ltd.

www.ampertronics.com.au

* Electronic Design * Custom Products * Contract Assembly

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I recall one-time programmable PIC parts, put them in the trash     when I got the ones with flash.     hehe.

my projects: https://github.com/epccs

Debugging is harder than programming - don’t write code you can’t debug! https://www.avrfreaks.net/forum/help-it-doesnt-work

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No that's the Erasable version. You expose the quartz window to UV to erase. With the newer chips (without the window) you need to drill a suitable hole on top instead..........

Well, of course, that's my whole point.  Erasable , not  Electrically 

 

I think I still have a pile of 2716's around here...wonder what program secrets they contain?

 

I recall one-time programmable PIC parts, put them in the trash     when I got the ones with flash.     hehe.

We had the OTP PIC parts, but also bought the erasable (EPROM) PICs for lab work ...a $1 chip vs a $7 chip.  We treated them like gold.

When in the dark remember-the future looks brighter than ever.   I look forward to being able to predict the future!

Last Edited: Fri. Jun 26, 2020 - 04:55 AM
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Other manufacturers also had (some still have?) One-Time Programmable (OTP) parts

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So, at one manufacturer, EPROM = Electrically Programmable Read Only Memory

At another manufacturer, EPROM = Erasable Programmable Read Only Memory

 

So, big deal. As long as the term is defined, somewhere, they are free to use acronyms as they see fit. Unlike a few places that have Language Police, we don't.

 

Jim

 

 

Until Black Lives Matter, we do not have "All Lives Matter"!

 

 

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This isn't about Maxim, or their datasheet, it is intended as a generic question.

 

Have many heard/used EPROM this way? Is this something recent/common?  Is PROM no longer used?  

Isn't your assumption be that it is erasable, or be surprised to find an EPROM that wasn't?

If EPROMs are purchased & found later they weren't erasable, that might cause some issues.   

Maybe since they are rarely used now, the term has been hijacked for other usages. 

 

 

 

 

When in the dark remember-the future looks brighter than ever.   I look forward to being able to predict the future!

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avrcandies wrote:
Have many heard/used EPROM this way? Is this something recent/common?

No.

 

It's always been:

  • ROM = Read-Only Memory: content defined at manufacture
  • PROM = Programmable ROM: content set after manufacture, but can't be changed (originally, programming was by blowing hardware fuses)
  • EPROM = Erasable PROM: can be restored to the original, blank, state ("erased"); thus allowing re-programming. Two types:
  1. UV-EPROM - erased by UV light;
  2. EEPROM - erased electrically

 

"Flash" is a type of EEPROM.

 

Often, "EEPROM" is taken idiomatically to mean a device specifically designed for non-volatile data storage

 

  Is PROM no longer used?  

As a technology, or as a term?

 

As noted, "One-Time Programmable" (OTP) is commonly used where the underlying technology is some sort of EPROM, but the erasure facility is disabled (eg, UV-EPROM chips with no window)

 

https://www.avrfreaks.net/commen...

 

So these are, effectively, "PROM".

 

 

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Thanks, that makes sense & aligns with common usage...if you blink these days, common usage seems to get stood on its head. 

 

Remember, a transformer is not a toy!

 

When in the dark remember-the future looks brighter than ever.   I look forward to being able to predict the future!

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In the past where  EPROM's with windows was common, you often could buy the same chip in a much cheaper plastic house, and that way they became OTP's.   

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More than meets the eye...

avrcandies wrote:

Remember, a transformer is not a toy!

Robots in disguise!

 

avrcandies wrote:
Have many heard/used EPROM this way?
On first blush, when I read the other thread, I thought it was a joke à la write-only memory...

"Experience is what enables you to recognise a mistake the second time you make it."

"Good judgement comes from experience.  Experience comes from bad judgement."

"Wisdom is always wont to arrive late, and to be a little approximate on first possession."

"When you hear hoofbeats, think horses, not unicorns."

"Fast.  Cheap.  Good.  Pick two."

"We see a lot of arses on handlebars around here." - [J Ekdahl]

 

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joeymorin wrote:
write-only memory... 

 

A classic:  http://repeater-builder.com/molotora/gontor/25120-bw.pdf

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SIGNETICS • 25120 FULLY ENCODED, 9046 X N, RANDOM ACCESS WRITE ONLY MEMORY

DS2502 1Kb Add-Only Memory

You can maybe understand my suspicion... ;-)

"Experience is what enables you to recognise a mistake the second time you make it."

"Good judgement comes from experience.  Experience comes from bad judgement."

"Wisdom is always wont to arrive late, and to be a little approximate on first possession."

"When you hear hoofbeats, think horses, not unicorns."

"Fast.  Cheap.  Good.  Pick two."

"We see a lot of arses on handlebars around here." - [J Ekdahl]

 

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js wrote:
With the newer chips (without the window) you need to drill a suitable hole on top instead..........

That's what I've been doing.

 

I think any modern EPROM is really an EEPROM.  I have never seen one with a window on top to erase in the past 10 years.  I think EPROM and EEPROM are synonymous these days.  At least in my conversations they are, but I wasn't around electronics in the days when EPROM meant a window on top to erase.

 

Was it possible to write to the windowed EPROMs without erasing them first.  Could you just overwrite, or would only the 1's get written so eventually you ended up with all the bytes being 0xFF?

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MarkThomas wrote:
Was it possible to write to the windowed EPROMs without erasing them first.  Could you just overwrite, or would only the 1's get written so eventually you ended up with all the bytes being 0xFF?

They were just like today's flash.  Erasing sets all bits to 1 and programming just wrote to the bits that were to be zeroed.  And also just like flash you can overwrite but you can only change a 1 to 0.  if bit is already 0 you can't make it a 1 (without erasing).

Letting the smoke out since 1978

 

 

 

 

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MarkThomas wrote:
Was it possible to write to the windowed EPROMs without erasing them first.  Could you just overwrite, or would only the 1's get written so eventually you ended up with all the bytes being 0xFF?

IIRC erased EEPROMs had 0xFF, so like flash you write the zero's!

 

Early in my career another EE team was scheduled to show their latest project to upper management, a big dog and pony show it was called.

All afternoon the EE's practiced there demo until all was ready for tomorrows big show.

The next day, was clear and sunny, and the every one paraded in to see the demo now awash with sun light streaming in from the windows!

The show did not go well, nothing seemed to work, the big brass was not impressed, and so left. 

Shortly after they left, the EE's and techs gathered around the table to start troubleshooting, as soon as one of the techs moved to the sunny side of the table, the project suddenly started to work!

One or more of the EEPROMs was light sensitive and one or more bits flipped in the sun light, in the shade it worked fine.

From that day on, everyone made sure to have covered the EEPROM windows before showing off their new toys.

Jim

 

 

(Possum Lodge oath) Quando omni flunkus, moritati.

"I thought growing old would take longer"

 

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That was also a  problem with common desk lamps that used fluorescent tubes. They can give off a fair amount of UV and if you brought that desk lamp down close to get a good look at the EPROM circuit, you sometimes went away with things worse than when you started.

 

I remember that one!

 

Jim

 

Until Black Lives Matter, we do not have "All Lives Matter"!

 

 

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IIRC erased EEPROMs had 0xFF

Unless you were using some National chips, they read as 0 when erased. Must have had an internal inverter.

John Samperi

Ampertronics Pty. Ltd.

www.ampertronics.com.au

* Electronic Design * Custom Products * Contract Assembly

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I start using my UV EPROM eraser again after 15 years. Last time I used it was with PIC12C509s. Except now it sterilizing masks, not erasing EPROMs.

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Early in my career another EE team was scheduled to show their latest project to upper management, a big dog and pony show it was called.

..

That was also a  problem with common desk lamps that used fluorescent tubes. They can give off a fair amount of UV

 

When I was in college some kid made an impressive "robot arm" with his 6502 (?) processor & the newspapers showed up for the grand unveiling.  The robot was doing its thing & the photographer started to take a few shots...the robot went completely bonkers, thrashing all around, and I believe couldn't be brought back to life even with a power rest.  Supposedly, it was discovered that the eprom glass was exposed & a bit or two was knocked out.  I wasn't sure whether to believe  it or whether the flash HV field "zap" was the culprit.  

However, it apparently can effect nuclear facilities:

 

Within 3 to 5 seconds of the second flash, Halon discharged from the overhead nozzles. The discharge occurred at 9:47 a.m. and lasted for 10 to 12 seconds. It was characterized by a loud roar, fog, and significant air turbulence. The discharge scattered loose papers around the control room and dislodged several ceiling tiles, support frame pieces, and lighting fixture plexiglass covers. One ceiling panel support piece broke the cover glass and bent the case fastener on a relay that provided backup line protection to a 345-kv line.

 

The licensee's discussions with the manufacturer indicated that a strong light source could cause an unpredictable perturbation within the EPROM, depending on the light intensity and the angle of incidence to the circuitry through the EPROM's window.

The licensee also ran tests using different light sources and different materials to mask the light flash from the EPROM. The tests confirmed that the more intense light from the old-style flashbulb strip on a Polaroid SX-70 camera triggered the EPROM at approximately twice the distance from the EPROM as the Canon digital camera. They also confirmed that the light from the Canon flash and the Polaroid flashbulb could be effectively blocked by "black bagging" the flash, or by blocking the EPROM window with "tin foil" held in place by clear cellulose tape, or by blocking the EPROM window with "standard electrical tape." 

 

https://www.nrc.gov/reading-rm/doc-collections/gen-comm/info-notices/1997/in97082.html

  

When in the dark remember-the future looks brighter than ever.   I look forward to being able to predict the future!

Last Edited: Sat. Jun 27, 2020 - 01:22 AM
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balisong42 wrote:

I start using my UV EPROM eraser again after 15 years. Last time I used it was with PIC12C509s. Except now it sterilizing masks, not erasing EPROMs.

Everything old is new again.

 

Brilliant!

"Experience is what enables you to recognise a mistake the second time you make it."

"Good judgement comes from experience.  Experience comes from bad judgement."

"Wisdom is always wont to arrive late, and to be a little approximate on first possession."

"When you hear hoofbeats, think horses, not unicorns."

"Fast.  Cheap.  Good.  Pick two."

"We see a lot of arses on handlebars around here." - [J Ekdahl]

 

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With my retro-computing activities, I recently noticed the eprom in a russian zx spectrum clone was sensitive to light. I'd not seen that effect before on western eproms, but then again, it could be the modern led lighting causes a problem? It was well known eprom parts like the Motorola 68701 were light sensitive due to the use of dynamic memory cells. As well, Nordic mention light sensitivity on some of their products in chip scale packages.

 

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It was common to stick opaque labels over the window in UV-EPROMS:

 

 

The primary purpose was to stop any light creeping in - but, as shown, they could also serve to identify what was programmed into the chip.

 

ISTR that there was a "bug" in the EEPROMs used in early Philips coded car radios - where the security code protection could be erased by simply putting the unit in a domestic freezer over night

 

 

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awneil wrote:
where the security code protection could be erased by simply putting the unit in a domestic freezer over night
Round here, we call that 'outside'.

"Experience is what enables you to recognise a mistake the second time you make it."

"Good judgement comes from experience.  Experience comes from bad judgement."

"Wisdom is always wont to arrive late, and to be a little approximate on first possession."

"When you hear hoofbeats, think horses, not unicorns."

"Fast.  Cheap.  Good.  Pick two."

"We see a lot of arses on handlebars around here." - [J Ekdahl]

 

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We had a similar problem #17 #21 in the past, it was a frequency converter that used die's, and for the press release it flipped out every time they took a flash photo.