UPD78P014 datasheet(23/62 Pages) NEC

23 / 62 page

µPD78P014

ERASURE PROCEDURE (

µPD78P014DW ONLY)

With the

µPD78P014DW, it is possible to erase (set to FFH) data written to the program memory, and rewrite the

memory.

The data can be erased by exposing the window to light with a wavelength of approximately 400 nm or less.

Usually, exposure is performed with ultraviolet light with a wavelength of 254 nm. The amount of exposing required

for complete erasure is shown below.

•

UV intensity x erasure time: 15 W•s/cm2 or more

•

Erasure time: 15 to 20 minutes (using a 12,000

µW/cm2 ultraviolet lamp. A longer erasure time may be

required in case of deterioration of the ultraviolet lamp or dirt on the erasure window).

Erasure should be carried out with the ultraviolet lamp placed at a distance of 2.5 cm or less from the window.

If the ultraviolet lamp is fitted with a filter, this should be removed before performing exposure.

OPAQUE FILM FOR ERASURE WINDOW (

µPD78P014DW ONLY)

An opaque film should be applied to the erasure window except when erasing the EPROM contents, in order to

prevent the EPROM contents from being unintentionally erased by light other than from the erasure lamp, and the

internal circuits other than EPROM from misoperation due to light.

ONE-TIME PROM VERSION SCREENING

One-time PROM versions (

µPD78P014CW and µPD78P014GC-AB8) cannot be fully tested and shipped by NEC for

reasons related to their structure. It is recommended that after writing the necessary data and storing at high

temperature under the following conditions, screening should be conducted to verify the PROM.

Storage Temperature

Storage Time

125

°C

24 hours

NEC provides charged services for one-time PROM writing, marking, screening, and verification, under the name

“QTOP Microcomputer”. Contact NEC for details.

UPD78P014 Datasheet(PDF) 23 Page - NEC