When men were men and chips had windows.

[Pommie]

Having a tidy out and came across this,

Not sure any of the newer members will know what the window was for.

Can't believe I used to wait 10 minutes for it to erase before programming again.

Maybe I should keep it so my great great grand children can take it on Antiques Roadshow.

Mike.

 

[Diver300]

The only processor in that package that I used was the one inside the PICstart Plus. The only UV source that I had was a lightbox for exposing UV light sensitive etch resist, which took overnight to erase the IC, but as the code was only changed when Microchip issued and update, I didn't mind.

One IC never erased a small section of memory, even after a weekend on the lightbox. Under the microscope, I saw a grain of dust on the chip itself, so I had to scrap that one.

Microchip stopped issuing updates in that form for the PICstart Plus, and instead had a daughter board that plugged into the DIL-40 socket. That replaced the processor with a QFP package that could be flashed without unplugging it from the computer.

 

[Nigel Goodwin]

I've still got a couple of UV erasable PIC's (12C508 and 16C71 as I recall), but not that low spec one

Basically the development of the 16C84 meant their end wasn't very far away.

I suggest you don't mention how much it cost!.

 

[Pommie]

I had a small dermatological grade UV exposure unit that erased in 10 minutes. I did a few project using windowed chips and programmed with a PICstart Plus. Still seems kinda cavemanish compared to today's flash chips. I've got a windowed 18F2550 somewhere - the first USB capable pic.

Mike.

 

[Pommie]

I suggest you don't mention how much it cost!.

I've no idea. I'm guessing back then they were very expensive but I bought everything via my company so didn't really know (or care) about the price. It was all research.

Just looked up the spec. Wow, 512 (12 bit) words of UVEPROM and 25 bytes of RAM.

Mike.

 

[rjenkinsgb]

I have a few early PICs plus boatloads of UV erasable EPROMs and other old eprom CPUs..
Those are a mix of ROMs from my early computer builds and ones for machine tools - a lot of the older control systems are based on EPROMs, though they are gradually becoming less common.
The oldest ones we work on were originally built with core memory, though that has been replaced with battery backed CMOS; but the rest of the original minicomputer is still in use.

 

[MacIntoshCZ]

How is that done? I mean erasing memory with UV light?

 

[Nigel Goodwin]

Just looked up the spec. Wow, 512 (12 bit) words of UVEPROM and 25 bytes of RAM.

I was given 200+ OTP PIC's, probably the 16C55 (or similar), I ended up giving them away on these forums - to a guy I met up with at a Radio Rally

We arranged to meet in front of the Russian Communications Truck - but he wasn't there?, eventually found out there were TWO trucks that year, and we were at different ones.

 

[Nigel Goodwin]

How is that done? I mean erasing memory with UV light?

That's how EPROMS worked - and those controllers used the same EPROM memory technology.

 

[Pommie]

Note, above I wrote UVEPROM which stands for Ultra Violet Erasable Programmable Read Only Memory. Now we have Electrically Erasable Read Only Memory (EEPROM). You kids today just don't know how easy you have it. OMG, turned into my dad.

Mike.

 

[rjenkinsgb]

A UV device eraser is pretty much a fluorescent tube that has no coating to filter convert the UV to visible light.
For many years I used a 12" fluorescent fitting with an appropriate tube in it and a couple of strips of aluminium glued to the tube end supports as raild for ICs to sit on..
A "Turn it on and leave the room rapidly" setup

This is a commercial UV device eraser, a box with a tube, drawer underneath and a timer:



Once programmed, UV erasable devices are supposed to have metallised labels stuck on, to block any trace of UV from sunlight that may slowly erase them.
Some people would use paper labels, tape or anything available - or just not bother.. The labels sometimes fell off anyway.
It looks like these started out with proper labels, from the outlines - but at some point they have been reprogrammed and improvised labels added, which have not all lasted.

 

[atferrari]

With Microchip I started with the erasable PIC 16C57 (now not even sure which one was the one time programmable).

Suspecting that the erasing could take too much time, I bought four of them, implementing a continuous merry go round of continuous erasing while debugging. Soon, a casualty (two OUT pins connected to each other) brought the number down to three.

Life forced me to become organized and soon as well, learnt what "divide and conquer" is.

Nigel Goodwin 's articles were a terrific guide.

 

[Nigel Goodwin]

With Microchip I started with the erasable PIC 16C57 (now not even sure which one was the one time programmable).

ALL were OTP, with the exception of the 16C84 (the PIC that changed everything) - for everything else you had to use the special, and VERY expensive, windowed devices as pictured at the top of this thread. The 16C84 used EEPROM technology, as did all the following erasable devices for a long time- including many that claimed to be 'flash' - AVR's marketing department started calling their EEPROM devices flash, and MicroChip followed suit. Eventually flash devices did start to appear though.

 

[atferrari]

ALL were OTP, with the exception of the 16C84 (the PIC that changed everything) - for everything else you had to use the special, and VERY expensive, windowed devices as pictured at the top of this thread. The 16C84 used EEPROM technology, as did all the following erasable devices for a long time- including many that claimed to be 'flash' - AVR's marketing department started calling their EEPROM devices flash, and MicroChip followed suit. Eventually flash devices did start to appear though.

Found my stock in the first drawer I looked for.

In the top row, the left one is OTP and the rest (the three I mentioned in my post) obviously erasable.
Below them, one 16C55 and two 16C54. They costed dearly down here.

 

[granddad]

Regularly did UVEPROMs in the office. printer firmware and comms stuff and the like .. i would send chips out , ask for old chips back. Must have saved the company loads, Mm they still made me redundant (Yippee)

 

[Nigel Goodwin]

I've still got a Kantronic Packet Modem somewhere - and I used to regularly update the firmware on it - for free, as an old friend of mine (who in fact I now work with) used to be the guy at the importers who dealt with Kantronics. So every time there was an update, he blew me a new set of EPROMS, and I give him the old ones in exchange.

 

[schmitt trigger]

Having a tidy out and came across this,
View attachment 130347
Not sure any of the newer members will know what the window was for.
Mike.

Put it on a nice frame...... with the datasheet’s first page on the side.

Would make a nice nostalgic display !

 

[granddad]

Put it on a nice frame...... with the datasheet’s first page on the side.

A future Antique ..

 

[unclejed613]

i have a box of UVEPROMs of various memory sizes.... there's even some Z80 and 8086 CPUs in that box...

as an aside, the "when men were men" part of the title made me think about early radio station equipment and their exposed wiring....

exposed antenna matching coils, exposed vacuum tube wiring... you had to be on your toes around this stuff....

 

[nsaspook]

From an old DIY computer of mine. Wire-wrap, classic UV, stacked memory chips on a Archer board.

**broken link removed**