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Chip on Breadboard - 2716 EPROM
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- Опубликовано: 16 янв 2017
- Reading memory locations in a 2716 EPROM (Erasable Programmable Read Only Memory). Erasing the EPROM using Ultraviolet light. Programming the EPROM using primitive (and frankly disreputable) techniques. Damaging the EPROM, but restoring its data in the process? Weird day :)
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It was quite common back in the day, that when rushing the erasure, an EPROM right out of the eraser would blank-check OK, but then after a couple of minutes it would turn out not to be erased successfully.
I think that the residual ionisation initially keeps the charge potential down, but when the chip stabilises and the memory cell gates become fully isolated again the charge is enough to open that cell transistor.
Similar memories here, seems to have been on Friday afternoons and involving one of the suits from the sales team wandering around mumbling something about promising to have the units shipped that day...
I think this is the most likely explanation!
Add the fact that the lamp in the eraser is old and possibly less effective than spec
This is a really good piece of info here.
I love how folks who had experience with the real stuff have such beautiful, priceless insight.
I never had to do this in my life, but this video got me interested in hooking up one of the EPROM chips I scavenged from old electronics, hook it to a microcontroller and getting some data out.
Although I have a very efficient UV exposure box I can use to erase, I will remember your precious words, @68Stan :)
Due to physical principles, UV light and above is all you need to erase it. You can go lower in wavelenght (higher energy) and itll work just as well. To make sure it wont get erased by ambient light, simply block UV content. Paper will efficiently block that due to the flourescent dyes it contains, it doesnt even need to be black.
The physical principle here is called the photoelectric effect, where single photons quite literally smash out electrons if the energy (frequency) is high enough. The intensity of the light determines the rate at which electrons are removed, so you could have it sit under a single led for a few hours or use a 400W UV thrower for merely a second.
The electrons, freed of their boundaries, will find a ground path themselves, theyll just stick into the next surface they can find. The UV light doesnt provide a ground path but just pushes them out with enough force so that they wont come back.
Thanks for that explanation.
How about an Arduino project to read the EPROM. You could use a counter chip to generate the address and a shift register chip to read the data into the Arduino. Use the Arduino to clock the counter and shift register. Display the results using the serial monitor.
If you look inside the chip with a microscope, you will see the transistors sitting by the seaside under an umbrella drinking a gin and tonic. They were protected from the UV rays!
This brings back memories of when I was a field engineer back in the late 70s. The factory sent me an updated EPROM. I had about 60 control panels that needed updating. So, pull all the chips out of the sockets and erase them. Then put the new EPROM in the DATA IO programmer, read the chip, then reprogram 60 chips one at a time. Ah, the good ole days.....
Hey, those bits have been hanging around since 79 or 80- they are not going to leave that easy ! They are laughing at your 'sunlight' and '45 ms' ! Ha !
The Z80 and EPROM videos are excellent, thank you Julian. They're the best demonstrations of how these things work I've ever seen. It helps knowing a bit to start with, but seeing this all in action with resistors and LEDs all at slow speeds is fantastic.
Best video I've watched for a long time.
I can't explain why, but getting back to the basics like this is just fascinating.
You have "refreshed" the memory as a residual charge has remained. This is the same principle as old DRAM used that needed refresh cycles.
i have experienced this exact same thing when designing my own eprom programmer 25 years ago !
I just learned how an eprom works, awesome! Thank you for your lesson, it really was a pleasure! :)
have fun with your eprom then.
👏 I've learnt more reading the comments for this video than from the all the other reading I've done on the subject over the last couple of days.
Thank you Julian for making this Z80 series, I myself have ordered a couple Z80 s and am hooking them up on a breadboard with indicator leds and so on. I would love to see more content about how to interact with and how to setup Z80s on a breadboard 😊.
Correction: "Z80 series" -> "series with stuff useful for the Z80"
I'd like to see the same, in fact anything other than "if I do this, an LED lights up..."
Here's an idea: use a TIL-311 hex display (x2), and tie them in place of the LEDs, and hook up the CD4060 (which you used in the birthday sound/light kit) to the address pins of the EPROM and you have a dirt-cheap EPROM reader! You can probably find some TIL-311s on flea bay.
Nice idea :)
why not to replace 555 with arduino, create time signal on some pin, connect EPROM output with arduino, catch data and transmit to PC as .hex file?
Love ths brings me back to my childhood. KEEP THESE COMING PLEASE!!
E000h is 57344 in decimal, in case it means anything. I still remember lots of ZX Spectrum addresses, 16384 for the screen being 6912 bytes long. 22528, the printer buffer, used for small machine code programs and hacks. Lots of memories. EPROMs were always a bit of a mystery to me so I enjoyed this a lot. Keep 'em coming Julian.
This takes me back to the 80s and the EPROM programmer add-on board I built for my ZX Spectrum. It also takes me forward to today and my deep appreciation for the wonder of serial EEPROMs :D
Nick B I appreciate serial roms but still.... I miss those address lines 😢
Thanks for the memories as an old Z80 guy the days where I not only wrote the code but also designed the hardware it ran on. It was amazing how much you could do in 2K of ROM I once implemented a full cockpit simulator and an interface to a minicomputer that handled the flight simulation. Later I used 8048 micros then switched to the Pic family.
This is brilliant - I'm in Old Geek Heaven
Thank you so much for this video, because I’ve been using an eprom and trying to figure out how it works, and this has helped a lot
My first Z80 computer had a 2716 EPROM and 6116 RAM, learned to program in HEX. Makes you optimize your code.
I still have it and it still works, mostly. Thanks for the videos. :)
"I need 25v +/-1v, i know I'll use three PP3's" - Arrrrrrrrrrrrrrrrrrrrrrrrrrrrgghhhhhhhhhhh, you have got to be the only electronics guy on the freaking planet not to have a rack of decent variable power supplies sitting in front of him.
"Oh, I need 12v, I know, I'll connect my solar panel via this buck converter via this boost converter powered by a USB thing to this capacitor and attach it to this piece of wood and then..."
JUST BUY A NORMAL VARIABLE POWER SUPPLY GOD DAMMIT!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
you are so annoying....
Just be pleased he used a proper eraser, I thought he was going to use the spark from the taser....
Actually when he was reading that bit about sunlight, I thought ...I know where this is going. Thankfully I was wrong.
A lot of his interesting power solutions make more sense if you imagine that he's absolutely terrified of AC power. At least that's the impression I get...
c'mon... that's half the fun... trying to work out what whacky way he'll power something... and he never fails to surprise ;) I think he is also showing how you don't need to be too technical (except when you do have to to be) to get by with a lot of stuff ;)
Great stuff Julian!
Made perfect sense till it failed in such an insane way!
woah. some old school electronics brought you by Jillian
12:39 NOOOOOOOOOOOOO!!!!!! This EPROM held the last remaining copy of the Voyager access codes! Now we're doomed to endure the same two hours of graphics demo in 2273 when V'Ger comes back instead of just telling it to shut up with a button on an old, dusty, almost 3 centuries old remote control. Thanks, Julian, well done.
Julian, I really enjoyed your video about the 2716 eprom. It brings back a lot of memories. Back in the day, I used an Intel Prompt 80/85 to program these chips. The Prompt 80/85 was built by Intel using their 8085 SBC. The unit had a hex keyboard & display and a ZIF socket that would accommodate 27XX series eproms. I used it to do firmware updates for a cash dispenser. Just Google Intel Prompt 80/85 for images of it..
A old trick i did was reading the eprom while in the eraser.
slowly you can see all bits going to one each read cycle....
This brings back memories, thanks Julian!
Ah! This brings back memories of 6502 assembler and the BBC B - I think I've got one of these somewhere :-)
I was thinking that I'll have to now dig out my BBC micro, my EPROM programmer and my stack of 2764s! I think they're all in the loft somewhere. And my eraser, that must still be up there too.
yeah the good old C64/Vic-20 days :)
I did write my 1st bit onto EEPROM i had an old computer power supply that had 24V output i was scared cz amps are high but somehow i manage to write it thanks for such awesome tutorial
EPROMs can be used one of two ways: to store code, or to store logic. Back in the 1970s/1980s, EPROMs were used for what is called "combinational logic." Combinational logic EPROMs act somewhat like GALs or PALs. Instead of thinking of the address pins as addresses, you can think of them as logical inputs. And, for each logical input combination, you can store a pre-determined output by storing it as data at that address. So for a 2716, you can have 2048 combinations of inputs and its resulting outputs. I've done this technique when I make a keyboard encoder. Each key switch has what is called a scan code. I use the scan code and send it to the EPROM through the address pins, and then output the corresponding ASCII code through the data pins. Combinational logic EPROMs are also used in memory boards to control the addressing when the usual 74-series chips used for this purpose does not suffice.
RetroComputerPorn. Love a good UVEPROM video. Clearly this is an example of time travel. Or maybe the OE/PGM pin was actually floating towards logic high when you checked for FFs when in fact you had not actually cleared the EPROM due to too short an exposure/old UV lamp. I prefer to think it is a clear example of time travel.
Excellent video Julian, it's interesting to learn about how these ancient memory ICs operate.
Brings back memories (?) of days spent indoors programming and erasing 2716/2616 then larger 25128 (when the price per meg came less then the price of a night out) EPROMS for projects.
Wow man black light!! Remember the glowing teeth, I had a nice one I picked up at the PX in Cam Rahn Bay back in 1970, hung it over my bunk so it shined on a poster I had that was sensitive to the light that was a sort of glowing shimmering spiral with the words, "What if they gave a war and nobody came!" emblazon over the pink spiral. Looked great when it contrasted with my camouflage color poncho liner that I used for a blanket in my old hooch. Sure brings back the memories. Although that was a good movie, that the poster referenced, we have yet to learn the true answer to that question.
These are great, thank you for doing this.
One thing that is missing -- a fuse. I don't know how many times I've fried chips because I did something very subtle incorrectly. A fuse is almost required when using NiMH because of the HUGE amount of current capacity. You can fry your chip and your breadboard by letting out all of the magic smoke.
Other than that I really love the video.
Ha ha all this z80 stuff is definitely going to be beyond me. Following along with interest :-)
Clean the window with window cleaner, invisible greasy finger marks cause reflection of the UV.
When I used eproms on Arcade machines, many years ago, we left them in the UV eraser for around 40 minutes.
Old multi used eproms would not wipe at all.
The chip just went back in time, nothing special really.
but there was no flux capacitor fitted :/
+PiezPiedPy it was clearly inside the black box.
its clearly grown immune to uv rays
I JUST did two videos showing the calculation and programming of EPROMs for cb radio frequency conversion, might be worth a look for some people if they are interested in seeing the entire process.
It is copyrighted in 1979 by AMD. The date of manufacturing is week 36 from year 1983.
Thanks for this video it helped me a lot for my little project.
Bravo Julian! Absolutely chuffed by this 1979 memory resurrection. Abba and the BeeGees would be proud. Very strange the UV light. Maybe try Tarot cards. Perhaps degradation in the IC?
I have written a full Z80 disassembler for Arduino based microcontrollers if anyone needs one. I wrote it for an unfinished ZX Spectrum related project. It uses the Adafruit 320x240 LCD and supports all undocumented instructions. I think I also did a version with composite video output.
I have also developed an Arduino based EPROM editor/programmer that uses PSION Organiser II Datapaks. It will copy/edit/program Psion Datapaks or, if you remove the EPROM from a Datapak and fit a ZIF socket, it can be used to program any 27(c)64 or 27(c)128 (larger capacity devices may follow if I need to use them). The project is called Datapak S4, the poor mans Dataman.
thanks for sharing these old methods..we young generation only read on book.
I have a huge collection of eproms of many sizes from 2716's through 27512's and larger including 16 bit wide 40 pin types. I also have a good stock of Z80B and Z80H chips (6 and 8 mhz), and some 80188's. Also many 128KB 8 bit wide srams. I'd love to build some sort of retro computer, but first I'd need an Eprom programmer. There does seem to be one on ebay for about $50 and a Linux cmd line program to drive it, but I've been wanted to build some sort of arduino based programmer for some time, with the one from Byte Magazine in mind for the programming voltage generator. (I'd use a ten turn pot with a counter knob to set the voltage).
like that oldschool basic videos!
Maybe while memory was hot, it seemed to be full of 0xFF, but after cooling back to room ambient temperature, it went back to previous data. Just my idea.
An EPROM cell is not digital. It holds an analog value (a charge) and a comparator is used to say if it's 0 or 1. You didn't fully erase it, but you adjusted the charges enough to get the comparator to detect them as 1. Modern devices can store 2 or 3 bits in each cell using several comparator levels.
You should read out the data again using different VCC voltages. That will change the internal voltages, so "half-way" bits can change.
A long time ago I tried to erase an EPROM by having it in sunlight for one day or so. No bits were erased. On the other hand, any light can can cause temporary bit flips, so the main reason to cover the window is to prevent temporary malfunction of the device. The risk for permanent erasure is very low. You need direct sunlight for a very long time to erase anything.
It might have worked with some decoupling caps for vcc and vpp.
When i used these things, years ago, I did find sunlight would erase them (yes even through the workshop window). Odd about the memory returning, but i do remember having to burn the buggers a few times occasionally. These things do have a limited number of write cycles, although usually in the tens of thousands of write operations.
I use these as solar cells. 2 of them will power a flashing oscillator on the kitchen window sill. Apparently no damage, one pair has been running for 2 years now :)
For a 50 ms pulse use the 555 timer in monostable mode. There are online calculators to figure out the resistor, capacitor values for a 50 ms pulse.
GNU/Bird Yeah that works too.
I bet the eraser was not on long enough to completely discharge the cells, but only lower the charge enough to look "blank" with the diode connected. I am guessing that the perhaps the programming pulse took what charge was left and re-programmed it back to a full charge.
ok.. i can say that this chip is trolling us all XD keep the good work m8 :D
Is it safe to connect microcontroller to address lines without any resistors? Or will it cause some overcurrent and burn somehing up?
And can i erase them with camera flash? How many flashes it takes to erase the sucker?
Fuck! You have the same doorbell as I do. I thought someone came to see me.
LOL! My neighbour has the same door bell as me - He bought his 12 months after me, so I am buggered if I am going to change my doorbell!!!! What happens for me is my button gets out of sync with my bell and it rings his door, and vice versa. That continues to happen until one of us re-syncs our button to our bell. I get endless joy out of pressing my doorbell button when his bell attaches itself to my button lol. Afterall his door bell rings have driven me nuts numerous times when I go to the door and there's no one there...
Local man sends eprom back in time. Macro quantum effect discovered. Expect a call from the Nobel Committee for Physics.
Brings back memories
The Z80 is so cool!
Indeed. Was reading this yesterday: www.righto.com/2014/10/how-z80s-registers-are-implemented-down.html
Very interesting stuff. Ever have thoughts about implementing your own CPU design?
Facinating!
I wonder if it's to do with the level of erase vs the voltage on the OE pin.
Perhaps if you put a pot on it you can get values between tri-state and data(old), and ff when fully enabled!
Presumably there is still something of a shadow of the old data there, but with proper ttl states on the inputs, you never see that!
Keep playing!
Hi Julian I like all your videos but this one in particular. Can't wait for the follow up video. You found a way to restore your secret and lost password encoded into the eeproms addresses 30 years ago :)
Great video, really looking forward to a follow-up!
...Well this isn't the video i was looking for but as it happens i have almost exactly two of these chips (32Kbit versions) that used to operate a 8085 although but fantastic an i think im going to be grabbing whats on them thanks to you.
There would be plenty of chance to accidental wipe it by sunlight if you were prototyping on a desk that gets enough sun (maybe even only mornings or afternoons) and you forgot to put your project away when not in use over a weekend. That's why they also had foil backed stickers to put over the window (other than a handy place to record version/date info)
Einstein's photoelectric effect causes the UV photon energy to be transferred to the trapped electrons. This gives them the energy needed to escape the trap and to be conducted by surrounding Si to ground. It is not necessary to remove every single electron from the trap in order for the circuitry to detect a 1 rather than a zero when the circuitry is configured correctly. By replacing the diode with open circuit, you have configured the circuitry incorrectly so that the few remaining electrons in the trap (i.e. floating gate) now are detected as 0 instead. In this mode ones will often be seen as zero if only a few electrons have found their way onto the floating gate... the data read will not be reliable and there is a possibility that floating this pin while using the chip will enhance the electron flow into the floating gates. This does give the possibility of recovering most of the data from a chip that was erased accidentally, however, but I believe the read rates will be low.
Given I=C dV/dt, I=30 mA, and dV=2 V, you can choose C to give dt=50 ms. This is less precise than a programmer and yet far more reliable than touching wires together. Vary C to improve performance and don't forget a parallel bleed resistor (~50 k) to reset the capacitor.
1:50 noooooooooo I like the 555 timer
where did you get those convenient leds with resistor legs? or did you make them yourself?
Thank you a lot.
How funny.
very educative video
We had several of these eProms. I remember we paid $75. U.S. for each of them back in 1979.
Perhaps the first few addresses are not designed to be erased, maybe by design, or maybe it needs to be left closer to 20 mins under the UV source to ensure a clean erase and no memory effect.
I know it probably wasn't your goal with this video, but you may have pulled that 555 to hastily from the breadboard, as providing a somewhat accurately timed pulse is one of the easiest applications for it.
"...the memory address E000...". I have never used a Z80. Still, it's just another CPU, right? Well, so what (or rather where) is E000? It's not anywere near the EPROM of course. A 2k-bytes EPROM goes from 0000h to 07ffh. It could be in another EPROM (the one left alone in the eraser?)... Anyway, this is great stuff, Julian. Thanks!
While you are on your way explaining about this type of technology, you could include the GAL/PAL chips. Maybe as bankswitching???
Interesting and strange results :D
Hello,how can i rise the miniPro programming voltage to 25v? The programmer has a 21v max voltage,i have to add the 4volts with a external supply or battery ,or pull out the pin and feed 25v from external supply?is time sensitive?edit: i pulled out the vpp pin and applied by hand 25V till the end, and it works! (on the miniPro)thank you.
at 10:04 I can feel the cpu's heartbeat
Ahhhhh, now you are talking my sort of language. As you will note from my channel, I deal a lot with old Fruit Machines, most which use a 27 / 27c (C type generally being the faster of the two) type EPROM's, and although quite rare for me to come across them, I have come across 2716 EPROM's previously, and do have a few in my spares bin, should you need any (They have all been UV wiped though, and I believe some work on 12.5v for programming)? Programmers for these smaller 27 series EPROM's, are unfortunately few and far between that are reliable, also noting the age of some of these EPROM's.
*WOW* !!! How the heck did you reprogramed the old data into the chip by just one bouncing contact :D you are the Uri Geller of the IT world xD xD xD
*bending metal was the past.... data recovery is the future!*
Cheers mate!
Hi
Eprom ic tm2764 vpp is 21v
What are replacement for this ic vpp 13v?
May i know brother?
Its pretty strange the erase didn't work! oO? Please do an update - I need to understand why the erase didn't work lol!!!! That's going to drive me nuts trying to understand why. EDIT: It's nothing to do with the 'inhibit' option - that's done using the CE apparently.
I think what 68Stan posted above it the most likely cause. On the same subject of ionisation - I've seen similar wierd things before where en EPROM can become light sensitive due to prolonged exposure to ambient light. I had an MVS game cart with a program ROM that suffered from this behaviour. When you covered the windows the cart failed the checksum tests, when you let ambient light into the window it passed 99% of the time. It took 2 or 3 attempts to erase that chip before it was completely erased, so maybe its the same problem here?
Hi i just purchased MX29F1615PC-10
Its a 42 pin flash prom and it is used
is it possible to erase the data on it with a Breadboard please let me know
This may seem dumb but what does the access time mean, am new to this?
Now I understand how they were able to reverse engineer the bios chip in Halt and Catch Fire.
very interesting video, thanks
There is a mystery a-foot my dear Watson. Can an Arduino be programed to deliver that 1 pulse.
this is old skool...... has to be a 555.
Hah! I remembered having something like those and indeed found three MBM2716s dated 81(33|43|45) sitting on a black foam bed in a plastic box. They've got stickers over the windows though so I'll be imprisoned if I remove them. >cough< Now to find a cheap UV eraser somewhere ...
Minor point but . . . Twenty One is not a hexadecimal value, it's decimal.
You mean 'Two One' in Hex, which is 33 in decimal.
What happens if you tie output lines to addresses and load some data in it? How fast will it jump from one address to the next?
This is how a "turing machine" works (just search on wikipedia). It's a ROM that takes as address some external imputs and some of the output bits. The output bits are the outpute. By properly programming the ROM it can do simple computations.
Can i programm an eprom mbm27C2564a with Arduino please ?
Fascinating!
Nice time machine.
I was going to ask about using a high power LED to erase it but I haven't found any high power LEDs at that short of a wavelength. the only LEDS of that wavelength are extremely expensive on the order of $100 for a 20mw LED. I suppose I could test it with a 365nm 10W LED and see what happens.
Is the age of the ultraviolet tube a factor? It might be worth giving it a sunlight erasure which would be useful data anyway since erasure units are still expensive. (If we get any sun that is).
Quite possibly a factor. An Arduino programmer and sunlight erasure would mean everyone can build a Z80 computer :)
I'm up for that. I've got a few 2716's and a Z80 but no eraser.
looking for z-80 chips now.
One thing I ran into doing this manually is that the hardware is "Indian" meaning the order read is reversed. Now check the data with an EPROM reader and see if you get same results.
It is "endian" not "Indian". ie. which *end* of a word (more than one byte) is stored first or in the lower memory address. (or disk sector, etc.)
what is that board called that he has the eprom chip in? the white one?
Breadboard?
Id say your UV light is showing its age, I used to erase many eproms at once years ago in a big unit, and that would take 20mins or so. I reckon a trip to a suntan studio, you could lay down on a sun bed next to your eproms and see if that works :-)
UNDELETE UNDELETE WHERE'S THE UNDELETE BUTTON
Oh. Its Julian.
+Luke Den Hartog he's a danger to society he can magically unerase EEproms :)
There's no facility that could hold him, he'd just manufacture a time machine and escape.
0:54 that was made in the 36th week of 1983 according to the date code.
What is the purpose of this "old school" project? I've only learned, I can put more 9V batteries in series using their own connections :) ... not much, but ... I'm trying to.
Why did he use a resistor to pull down CE? Couldnt you just use a 0 Ohm/Jumper?
Did you using power bank on the breadboard?