ofir,

When EEProm was fist available in the early 80's, it was used largely for storing auto-dial phone numbers in phones. It allowed information to be saved even if all the power was turned off... its non-volatile.

The other reason why it fit this market so well is that its easy to change the values. This type of use, storing settings and brief data for operation during the next power cycle still characterizes its use. The chips are designed for very high write cycle lifetimes, so they can be written and changed many times.

The products are not used like RAM. If you constantly wrote values to EEProm in leau of more RAM memory, it wouldn't take too long before the storage would fail. Its best therefore for calibration, settings, serial numbers, datalogging storage, etc.

FLASH is the successor to EEProm. Its got some nice attributes but you have to watch the write cycle lifetime figures because they generally have about one tenth that of EEProm. Flash is largely used as EProm/Prom/Rom once were, to hold a program or large datablock that may require downloaded upgrades.

Some use FLASH more like EEProm, but there are tradeoffs. EEProm are generally designed for R/W access at the byte level. When you write, the cell is erased and your new data is burned in. FLASH tends to be designed only erase large blocks at a time, after which you can write once over each of the erased bytes. So, its not as ideal for storing setting changes becasue you must erase so much before you update - and Murphy's Law would suggest that as you held all the data in RAM while the FLASH was erasing, you'd lose power and all your info.

aka J