Cloning this IC - Page 1
Forum section: electronics / general

author: yvautrin
author_rank: Contributor
timestamp: September 22, 2019, 10:30:17 am
content: Hello all, I am new in this world, and will apreciate your help!I have been asked to clone some IC, so I ordered some blank ones of exactly the same type!Now, where to start from? I have a pickit 2 usb module, how should I proceed to first copy the Hex from the original, and then to write the blank ones?Lep appreciated!

author: amspire
author_rank: Super Contributor
timestamp: September 22, 2019, 10:56:19 am
content: You will need an EEPROM Programmer that supports that memory IC.One that has been discussed in this forum that is pretty good is the TL866II Plus. Avoid the earlier models of the TL866 - they are now obsolete.http://autoelectric.cn/EN/TL866_main.htmlYou want to make sure that you get a genuine model and not a clone, but it sounds like the devices on eBay and AliExpress now are geniune.There are cheaper programmers, but you have to check they support the IC you want to program. Cheaper programmers can be a lucky dip.

author: amspire
author_rank: Super Contributor
timestamp: September 22, 2019, 12:59:06 pm
content: It is possible to make your own microelectronic circuit to program this chip, but you have to precisely follow the details in the data sheet. You will need the ability to increase Vcc from 5V to 6.25V and to apply 12.5V to the Vpp pin.The risk is if you do not get the programming just right, you may not fully set the programmed bits, or you might damage the chip. Using the commercial programmer is a much easier solution.Richard.

author: yvautrin
author_rank: Contributor
timestamp: September 25, 2019, 10:48:20 am
content: So, I now got my hands on a TL866 II Plus, what are next steps? (ok, install the software first! )Then read the original IC?I got the specsheet for the blank ones.Just don't want to avoid beginner's mistakes!Thanks all for your appreciated help!

author: amspire
author_rank: Super Contributor
timestamp: September 25, 2019, 11:01:34 am
content: It is a bit out of date, but you can look at Dave's EEVBLOG video on the original TL866:The steps will be to read and save the contents of the existing EPROMS first, and then program the blank ones.I do not have a TL866, but some programmers can automatically detect the chip type. Otherwise you need to select the correct chip type manually.If you are really nervous about accdentally damaging the original chips, practice on a blank chip first. Put it in and read it - it will be all zero's or FF's. If the TL866 II interfaces allows you to change the data, go and change some bytes to something else and try writing back to the blank chip. Use the blank chip for practice until it is easy. You will be able to erase the blank chip when you are finished.Once you see how it works, it will be very straightforward.

author: yvautrin
author_rank: Contributor
timestamp: September 25, 2019, 11:41:56 am
content: Thanks for your reply!The IC I have to clone is OTP ROM, so i won't have the chance to erase it if i fail! I ordered more chips that I need, so i can afford to loose one or 2 (they are 2&/piece!)Any ore advices!thanks

author: amyk
author_rank: Super Contributor
timestamp: September 25, 2019, 11:53:04 am
content: I looked at the data sheet more carefully, and yes it does say "one time programmable EPROM" --- I thought the "E" meant "erasable"?Anyway you can buy other EEPROMs to practice on if you really feel unsure about how to operate the programmer, but I wouldn't worry about it.

author: yvautrin
author_rank: Contributor
timestamp: September 26, 2019, 03:19:06 am
content: EEPROM = electrically erasable programmable read-only memoryEPROM = erasable programmable read-only memory (UV erasable)

author: james_s
author_rank: Super Contributor
timestamp: September 26, 2019, 05:21:03 am
content: EPROM is often used to describe OTP ROMs too, though not strictly correct. There are less expensive OTP ROMs that are identical inside to EPROMs but lack the expensive quartz window that allows erasing them.Either way it's pretty simple, select the correct chip in the software, read the original chip, optionally save the buffer as a file, look at the data in the buffer to verify it looks right. Then insert the blank and click Program.

author: yvautrin
author_rank: Contributor
timestamp: September 29, 2019, 05:10:55 am
content: Here we go, got a TL 866 II+, can read the original IC, save the .bin, check the blanks one, it is not all FF , now i am confused with the VCC and VPP, the datasheet says programming voltage OE/VPP = 12.75V with VCC 6.25V so what shouldI select in Xgpro ...

author: yvautrin
author_rank: Contributor
timestamp: September 29, 2019, 05:55:18 am
content: forgot to post the screenshot of the "blank" one...

author: yvautrin
author_rank: Contributor
timestamp: September 29, 2019, 06:53:34 am
content: so basically, i am f***ed... as they sold me non blank chips that i can not erase....

author: yvautrin
author_rank: Contributor
timestamp: September 29, 2019, 08:25:45 am
content: Will a medical grade X ray do the trick? A friend of mine runs a clinic here, so i might try it, but what about frequency? exposure time, etc....

author: voltsandjolts
author_rank: Unknown
timestamp: September 29, 2019, 09:16:53 am
content: There is small chance you could use these "new" chips if they have enough blank memory remaining to hold your code.If upper memory is blank and your system does not need all address lines, e.g. tie top address line high to use upper half of chip.

author: fchk
author_rank: Frequent Contributor
timestamp: September 29, 2019, 09:23:40 am
content: Digikey sells 1092-1021-ND MX29F800CTTI-70G.Datasheet:https://www.arrow.de/products/mx29f800ctti-70g/macronix-internationalThis chip can operate in x8 or x16 mode. You will have to make a little adapter board.It's a flash chip, so it's erasable.Alternative:Digikey sells AT27C080-90PU-ND. This is a drop-in replacement for your chip, but OTP and quite expensive.fchk

author: yvautrin
author_rank: Contributor
timestamp: September 29, 2019, 10:15:39 am
content: There is enough space on the "blank" chips to upload the program from the original one, but how do i do that, and how the system they go on will know which to start reading the program...?

author: Nusa
author_rank: Super Contributor
timestamp: September 29, 2019, 10:57:08 am
content: Quote from: yvautrin on September 29, 2019, 10:15:39 amDoes the original program use less than half the space? Does the 2nd half of the replacement chips read as blank? Those are things you can check. If so, you can program the 2nd half, and then use the address line trick mentioned above to make it read as the first half when you install it. Otherwise, you're still screwed.

author: yvautrin
author_rank: Contributor
timestamp: September 29, 2019, 11:02:41 am
content: yes, I guess the original program uses less than half the available memory.The program starts is from address 0000-0000 to 003-1390, then from 003-13A0 until the end 000F-FFE0, it is all "00" with just 2 bits in the last line (000F-FFF0)So, how do I do the "address line trick"...?

author: voltsandjolts
author_rank: Unknown
timestamp: September 29, 2019, 11:08:35 am
content: You could short the high address line to VCC. But cut the pinA18A19 so when you plug it into your system, the pin is not connected to the bus (it would short 5V to the bus lineA18A19). Your system reads from address 0 as it did before, it doesn't know it is 'halfway' through memory.Edit:Oh crap! I meant A19, which is high address pin, not A18.Remember, your 'new' code must also use less than half the memory for this to work.If you program the chip before connecting A19 to VCC, you must tell your programmer to start programming from halfway address 0x80000 (instead of 0x00000)If you program the chip after shorting A19 to VCC, you must cut/lift that pin so it is not connected to programmer tool. It will then complain about pin disconnected but you should be able to continue anyway (depends on programmer tool).

author: amspire
author_rank: Super Contributor
timestamp: September 29, 2019, 11:12:37 am
content: Quote from: yvautrin on September 29, 2019, 11:02:41 amYou copy the first 512K of the originals to the second 512K of the chips you have.This of course only works if the programmer will let you write anything to this OTP EEPROM. You may find all writes disabled.Then you need to tie A19 high (pin 1). If the chip is in a socket, bend pin 1 up so it is not in the socket and add a wire from Pin1 straight across to VCC (pin 32).Also, you can look at the much cheaper smaller chips like the AC27C040 (512K) or even AC27C040 if you only need 256K. These chips will probably plug straight in.

author: amyk
author_rank: Super Contributor
timestamp: September 29, 2019, 07:59:46 pm
content: In my experience it is very uncommon for ROMs to use less than half of the available space --- otherwise, the manufacturer would've used the cheaper smaller part.

author: james_s
author_rank: Super Contributor
timestamp: September 29, 2019, 10:06:10 pm
content: Quote from: blueskull on September 29, 2019, 07:00:53 amSeems like I read somewhere someone tried using xrays to erase a non-windowed EPROM and while it did erase, it also ruined it, it could not be reliably programmed again.I think it would require a much longer exposure than you typically get from a medical or dental xray system in stock form. I do have some dental heads I could experiment with giving a ROM a series of long low power exposures. These tubes are capable of much longer exposures than typically used as long as the power level is kept low. Anode heat capacity is the limiting factor.

author: yvautrin
author_rank: Contributor
timestamp: October 08, 2019, 06:01:56 am
content: ok, it did not work, not enough space left on the supposed to be blank chips...Can I replace the blank one with another type of eeprom? (I live in Egypt, so options are limited), if yes, which type of IC would you recommend?