UPD78P324 Datasheet, PDF (22/80 Pages) NEC – 16-/8-Bit Single-Chip Microcomputers

µPD78P324, 78P324(A)
4. ERASURE CHARACTERISTICS (µPD78P324KC/KD ONLY)
The µPD78P324KC/KD can erase (FFH) the content of the data written in the program memory and perform
rewriting.
The data content is erased by radiating light with a wavelength shorter than about 400 nm on the erasure
window. Normally, ultraviolet light with a wavelength of 254 nm is radiated. The volume of light required
for erasing the data content completely is as follows:
• Ultraviolet ray intensity x erasure time: 15 W·s/cm² or more
• Erasure time: 15 to 20 mins (This is so when using an ultraviolet lamp of 12,000 µW/cm². However, a
longer time may be required due to performance degradation of the ultraviolet ray lamp or dirt
deposited on the erasure window, etc.)
For erasure, make sure to place the ultraviolet ray lamp at a location within 2.5 cm from the erasure
window. If the ultraviolet ray lamp is equipped with a filter, make sure that the filter is removed for radiation.
5. ERASURE WINDOW SEAL (µPD78P324KC/KD ONLY)
If the erasure window part of the µPD78P324KC/KD is exposed to sunlight or fluorescent light for too long,
the EPROM data may be erased or the internal circuits may malfunction. To prevent such an accident, please
ensure that the erasure window part is covered with a protective seal except when the data is going to be
erased.
The EPROM package with window is shipped with a protective seal that is NEC’s guarantee of quality.
6. ONE-TIME PROM PRODUCT SCREENING
Structurally, it is not possible for NEC to test the one-time PROM products (µPD78P324GJ-5BJ/(A)/(A1)/
(A2) and 78P324LP/(A)/(A1)/(A2) completely before shipment. Therefore, it recommended that, after writing
the required data, the screening be implemented to verify the PROM after storing the product in the
following temperature and condition.
Storage Temperature
125 °C
Storage Time
24 hrs
NEC provides at a charge services including the one-time PROM writing, sealing, screening and verifying
under the title of QTOP microcomputer. For further details, please contact an NEC salesperson.
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