edit content 95020WP? - Page 1
Forum section: electronics / beginners

author: legepe
author_rank: Contributor
timestamp: May 04, 2016, 03:29:56 pm
content: Hi all,Recieved today the mini pro tl866cs and want to copy the contents of a 95020WP, erase it, edit the content then copy back to the 95020WPFirstly, there is no marking on one of the corners of the eeprom to identify which way it should be inserted to the programmer. Can someone please tell me how to identify which way it should go...My other concern is that it is WP.. which i understand stands for write protect. will this be stright forward to copy and edit the data or could i possibly do some damage?I'm brand new to this kind of thing and don't want to make any mistakes...Your advice is appreciated...legepe

author: newbrain
author_rank: Super Contributor
timestamp: May 04, 2016, 08:43:18 pm
content: The datasheet is always a good source for this kind of information.If the package is a SO8 (possibly the most common?), you'll notice that one of the edges is slanted.See the picture below for pin numbering:with the slanted side on your left, pin 1 is top left, usual counter-clockwise numbering.As for WP, according to the ST datasheet, the W stands for 2.5V to 5.5V operating voltage, and the P for Rohs compliance.

author: rstofer
author_rank: Super Contributor
timestamp: May 04, 2016, 09:44:08 pm
content: Were it me, I would build a little test jig with an Arduino or even a Raspberry PI (better choice). I would NEVER rewrite the original EEPROM, instead I would put a solid ground on Pin 3 - W' (logic '1' on Hold' as well) to prevent write and hold operations. Then I would get some other chips (they are available on eBay among other places) and DigiKey has them for $0.23. I would only write to the new chips. That way, I'm never any worse off than when I began.I would write a little Python code to grab the data from the original and store it. On the Raspberry PI, that would be to a file. You can then edit the file to contain whatever you need and use another little bit of Python to write the new chip. Example Python code for SPI comes with the device. It will be on the SD card after it is initialized.Here's a tutorial that uses C++:https://learn.sparkfun.com/tutorials/raspberry-pi-spi-and-i2c-tutorialHere's the datasheet:http://pdf.datasheetcatalog.com/datasheet2/6/0rqy30h78u9fxcfuhqxc90tifxyy.pdfYou can find Python examples on the Internet.

author: wraper
author_rank: Unknown
timestamp: May 04, 2016, 09:49:31 pm
content: Quote from: rstofer on May 04, 2016, 09:44:08 pmSo much hassle to just edit eeprom contents? I would understand if you already have RPI and want tinker with it, but seriously?

author: rstofer
author_rank: Super Contributor
timestamp: May 04, 2016, 10:29:49 pm
content: My primary concern in a project like this is to not lose the original EEPROM contents. Nothing else matters! In the end, I won't be any worse off than I am before I start.The next problem is how to extract the SPI data. There are a lot of microcontrollers that can handle SPI. Almost all of them, in fact. But what to do with the data I read? I might want to put it somewhere while I figure out what to change. Maybe I want to print it. It could be that I already know which bytes to change. In that case, I would just read a byte, substitute if necessary and write a byte. There would be no need for storage, just two chips on a breadboard with something driving the SPI bus.But we don't know! Nothing was said about how the changes would be implemented.Since I can easily read SPI on a Raspberry PI and it already has a file system for saving the contents, sure, I'm going to do it that way. It helps that I have a couple of PIs sitting here. The alternative might be an Arduino because there is already an SPI library. But storage is something that needs to be built, it isn't included in the box. More work... Using raw hardware (like a PIC) is just too much effort. First I have to get SPI working, then I have to read the data and then what? I guess I could use a Basic Stamp and bit-bang the SPI but that seems like a lot of work.No, I'll take the high level approach and use a board with a file system. I just know I'm going to want to print the file...

author: wraper
author_rank: Unknown
timestamp: May 04, 2016, 10:46:15 pm
content: Quote from: rstofer on May 04, 2016, 10:29:49 pmWhen you have such priority, you do not tinker with the hardware and software to just read a few chips. Because it would be barely tested, not a kind of permanent construction, and shit happens.

author: rstofer
author_rank: Super Contributor
timestamp: May 04, 2016, 11:13:23 pm
content: Quote from: wraper on May 04, 2016, 10:46:15 pmI can't overwrite the original if I pull pin 3 to ground. Now all I have to worry about is getting Vcc and Gnd on the proper pins and dealing with SPI. Personally, I would put a 330 ohm resistor in series with each signal (MISO, MOSI, CLK & CE). It won't hurt the signal levels but it prevents any kind of short circuit damage.The package for this devices implies that I will need a dip adapter before I can breadboard it. I'm not much into using bits of wire. For the very reason you suggest, I don't want to have a problem. If I were truly paranoid, I would write and then read back from one of my replacement parts before I ever even thought of plugging the original into the breadboard. Debug the breadboard before exposing the original.In everything I do, I try to ask myself "What can go wrong?". Because, you're right, bad stuff happens. But it happens less often if you stop and think about what can go wrong.I'm assuming that whatever this EEPROM goes in is important enough to protect. If not, why do this stuff at all?

author: legepe
author_rank: Contributor
timestamp: May 05, 2016, 09:09:08 am
content: Thanks for all your replies… some really useful information…As I’ve already said, I am an absolute beginner and was thinking that copying the data from the 95020WP would be as simple as pressing a few buttons in the software interface that comes with the TL866CS.Firstly, with the TL866CS - I’m assuming it will not work at all withwpeeprom’s? and Ive just realized it won’t work on win7 64bitThe 95020WP is out of a second hand speedo head where I need to correct the mileage… before installing it in my vehicle. (The second stage will be to correct the mileage in the BSI unit to match the speedo head)I therefore not only need to copy the data from the 95020 but find a way to locate the mileage within the data then edit and copy it back… or would I be better simply reading the data and editing it within the 95020Any further help will be appreciated…legepe

author: wraper
author_rank: Unknown
timestamp: May 05, 2016, 09:13:19 am
content: Quote from: legepe on May 05, 2016, 09:09:08 amIf you just want to replace the old faulty unit, then copy eeprom contents from it and write to the eeproms in the replacement unit (make a backup of them first, just in case).

author: legepe
author_rank: Contributor
timestamp: May 05, 2016, 09:22:17 am
content: Will i be able to do that with the TL866CS?

author: wraper
author_rank: Unknown
timestamp: May 05, 2016, 10:51:36 am
content: Quote from: legepe on May 05, 2016, 09:22:17 amwhy not? All the same, just no need to edit (unlikely to be easy due to the lack of expierience, unless someone tells particularly what data and how to change it).

author: rstofer
author_rank: Super Contributor
timestamp: May 05, 2016, 02:48:17 pm
content: Quote from: legepe on May 05, 2016, 09:22:17 amAccording to this document, the TL866CS will work on 32 and 64 bit Win 7:http://www.autoelectric.cn/minipro/miniprosupportlist.txtIt also has the W package listed but I'm assuming it requires an IC adapter. There are TL866 adapters available for the purpose. No, I don't know exactly how to buy them.I haven't chased down all the package dimensions but the one that stood out is the 0.05" pin pitch (1.27mm). Perhaps something like this Schmartboard will work:http://schmartboard.com/schmartboard-ez-1-27mm-pitch-soic-to-dip-adapter-204-0004-01/It certainly looks like the SO8N package has the same pad locations as an SOIC. Maybe the only difference is the sloped edge or some other cosmetic feature. But, again, I didn't chase down all the details.The programmer software will allow you to edit the EEPROM. It won't allow you to print a reference document.It seems like you have some soldering and unsoldering to do. Unless there is some other way...

author: legepe
author_rank: Contributor
timestamp: May 05, 2016, 03:16:26 pm
content: I have some adapters that physically allow me to connect the eeprom to the programmer... Ive located the sloped edge so I can position the eeprom correctly in the programmer, but before doing so, is it completely safe to read and copy all the data (make a back up) using the TL866CS in the 95020WP with it being (WP) write protected?

author: wraper
author_rank: Unknown
timestamp: May 05, 2016, 03:31:07 pm
content: WP is what written on them. Actually they are something like ...WMN-6P, W for power working voltage range, P - lead free. Ebay is full of cheap SO-8 ZIF adapters, actually they are pretty good. With one I programmed more than 2000 eeproms and it's still like new.

author: rstofer
author_rank: Super Contributor
timestamp: May 05, 2016, 03:41:15 pm
content: Quote from: legepe on May 05, 2016, 03:16:26 pmThis WP thing has absolutely nothing to do with write protection. Read the datasheet! The W gives you the working voltage range (2.5 - 5.5V) and the P indicates RoHS lead free. Page 35 here:http://pdf.datasheetcatalog.com/datasheet2/6/0rqy30h78u9fxcfuhqxc90tifxyy.pdfCompletely safe? With no experience, no helping hand? Probably not. If you can buy other chips, why not experiment with them first? They will come blank (contents probably 0xFF). You can write new data and read it back, erase the device, rinse and repeat. You can do it dozens of times until you are absolutely convinced that you know what you are doing and then go for the real chip. "What can go wrong?" is something you should think about. Treat that original chip as though it were gold.

author: legepe
author_rank: Contributor
timestamp: May 05, 2016, 03:47:56 pm
content: Thanks a lot for your advice... i will do what you say and get myself some blank chips.. I was looking on ebay and there are a few variants ie SOP-8 95020WP 4Kbit, 2Kbit and 1Kbit Serial SPI Bus EEPROMHow can I know exactly what the device is?The full number on the device is 95020WP Then below is K835S

author: rstofer
author_rank: Super Contributor
timestamp: May 05, 2016, 04:13:05 pm
content: Quote from: legepe on May 05, 2016, 03:47:56 pmPage 35 of the datasheet! The 010 is 1k, 020 is 2k and 040 is 4k bits.

author: legepe
author_rank: Contributor
timestamp: May 05, 2016, 04:39:18 pm
content: Thanks for your patience... i will dedicate more time to finding information..