12. EPROM, Erasable PROMs

• EROM characterestics are:

  • Can be written several times.

  • Offers further flexibility during system prototyping.

  • Can be erased by exposing to ultraviolet light.

  • Cannot erase contents of selected locations.

  • All content is lost on re-write.

• Electrically erasable PROMs, or EEPROMs.

  • Contents are electrically erased.

  • No need to erase all contents

  • Typically a subset of the locations are erased as a group.

  • Most EEPROMs do not provide the capability to individually erase contents of a single location.