I got these EEPROMS lately and I want to use them for other projects, so I need to erse/write them.
I have Arduino Mega, powered by 12V power adapter and I am creting a shield with ZIF connector for many different use, one would be programming those EEPROS (other are to test ICs and such).
The datasheet states 12V on some pins to writing it (under some combination of 0v/5V other pins), 14V (and other combination on other pins) for erase.
I found some suggestions over the net, that even only 12V does work for erasing (or more preciselly there was writenn something like you need 12V here and this program for writing, that program for erasing with your Arduino)
But on the other hand I found a lot of advices about Arduino on net, which was not working flawlessly/everytime/at all as too much folk anyone with Arduino just write some lores and believes as facts the moment they buy it.
It would be handy for me, to be able use only 12V for experiments, but do not want destroy those EEPROMS accidentally. On the other hand buliding 14V from what I have just now would take me too much work and time.
My questions are:
- May be it possible, that 12V is enought for erasing the chip, or it is more probably just nonsence?
- Is it possible, that I will permanentally damage the EEPROM by trying it erase by only 12V (few times over few days), or the EEPROMS would be OK, just not erased fully/permanentally/at all?
(If the worse that can happen is to not erase the EEPROM, or erase just some cells and have bad values here and there, or erase it but that it would refresh/forgot some bits later over few days, so just bad values would appear there,
BUT if after proper 14V erase it would work again OK, I will try it and see, if I can use the results for short experiments, before getting better equipement.
BUT if there is risc of permanent damage, I would not try anything and postpone my experiments moth or two, until I get better equipement)
Than you for your insight
Best Answer
According to the W27C512 datasheet it needs 13.75~14.25V. This tight voltage range is specified to ensure that all chips will erase properly despite process variations. A lower voltage is unlikely to damage the EPROM. It will probably still erase properly down to some lower voltage, but the actual limit is not known and will vary between individual chips.
I tried using 12V and it appeared to erase my W27C512 successfully. However I only verified it at 5V so it is possible some cells didn't erase fully (the datasheet suggests verifying at 3.75V to "ensure a substantial erase margin"). If your chip erases at 12V and verifies at 3.75V then it should be OK for experimenting. Just be aware that programmed data might become corrupted, and don't use it in a critical application.