Erasing an EEPROM chip

[jsbush]

I'm trying to gather information on how to erase EEPROM chips, essentially writing zeros to it to return it to its original state.


Is this possible by applying low voltage to it, or something low tech without having to use expensive EEPROM programmers?


Thanks

 

[blahblah99]

Yeah, depending on the EEPROM. You may be able to emulate a sector erase or device erase by hardwiring the clks and control pins using wires.

 

[Description]

What sort of EEPROM? Many of them have the clear window for UV erasure.

 

[jsbush]

Heres the datasheet for it

http://ww1.microchip.com/downloads/en/DeviceDoc/21073j.pdf

 

[blahblah99]

Originally posted by: Description
What sort of EEPROM? Many of them have the clear window for UV erasure.

Probably not. You're confusing it with EPROM, which does have a window.

 

[blahblah99]

Yes, it's possible but you will have to mimic the I2C bus using wires.

Look for a parallel port I2C circuit on google and that will do the trick.

 

[bobsmith1492]

They are erasable, hence the extra E. I seem to recall seeing devices that erase EEPROM, sort of like a battery charger. Not sure what they're called, though. Check an electronics catalog.

 

[Mark R]

Some EEPROM chips have an erase command. You just need to send this command and wait for the command to complete.

This chip uses byte-by-byte programming, so you will have to program each byte individually.

Note that this chip has a write protect function which can protect parts of the chip from erasure - once the WP function is activated it cannot be deactivated or changed.

You will, of course, need a circuit that can interface to the chip. This can be a full blow programmer, but it could be done by connecting the appropriate pins direct to the parallel port on a PC and running suitable software on the PC.

 

[Matthias99]

Originally posted by: bobsmith1492
They are erasable, hence the extra E. I seem to recall seeing devices that erase EEPROM, sort of like a battery charger. Not sure what they're called, though. Check an electronics catalog.

The extra E is is for 'Electrical'. 'Regular' EPROMs are erased by exposure to UV light. EEPROMs can be erased with appropriate control signals.

EPROM = Erasable Programmable ROM
EEPROM = Electrically Erasable Programmable ROM

 

[beansbaxter]

Just get a programmer and the software for the programmer should run a read/write once and suppress all the data to zeroes.

I would be highly shocked if there isnt a default way to erase the chip, unless (and I doubt) it is read only.

No different than doing the DSS hacking which involves a programmer, a looper, and a "chip"ped card that is being hashed.

 

[Fencer128]

Originally posted by: beansbaxter
Just get a programmer and the software for the programmer should run a read/write once and suppress all the data to zeroes.

I would be highly shocked if there isnt a default way to erase the chip, unless (and I doubt) it is read only.

No different than doing the DSS hacking which involves a programmer, a looper, and a "chip"ped card that is being hashed.

I think he's trying to do it without the aid of a programmer.

Mind you, basic EEPROM programmers can be quite cheap now.

Cheers,

Andy

 

[AbsolutDealage]

As an aside, EEPROM's and the like are actually '1' in the default state, not '0'.

 

[bobsmith1492]

Eh, first E, second E, whatever... 🙂

Anyway, take a few capacitors from tvs, monitors, and computer switching power supplies and hook 'em up in parallel. Connect a bridge rectifier in series with a 120 v light bulb to the main power lines and use it to charge the caps to about 150v DC. Discharge the caps across the EEPROM. Bingo - no more data on THAT chip!

 

[Peter]

*ahem*

As AbsolutDealage said already, empty EEPROMs contain all '1' not '0'.

Depending on the type of EEPROM and what it's attached to, there may or may not be a software operated method of erasing it in-circuit. If there is, you need the exact software written to do it. Typically, this is unavailable outside the place that manufactured the circuitry.