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Chapter 8 Appendices
136
EPROM Versions
8-1-6
Cautions on Operating the ROM Writer
■ Cautions on operating the ROM writer
(1)The Vpp programming voltage for the EPROM versions is 12.5V.
Programming with a 21-volt ROM writer can lead to damage. The ROM
writer specifications must match those for standard 1-megabit
EPROMS:Vpp=12.5V V;tpw=0.2ms.
(2)Make sure that the socket adapter matches the ROM writer socket and
that the chip is correctly mounted in the socket adapter. Faulty
connections can lead to damage.
(3)After clearing all memory of the ROM writer, load the program.
(Write the data X'FF' on the address X'0000' to X'7FFF'.)
(4)After confirming the device name, write the addresses from the start to
the final address.
(5)The option bits for supporting the mask option are prepared at the final
ROM address.
This writer has no internal ID codes of Silicon Signature and Intelligent
Identifier of the auto-device selection command of ROM writer. If the
auto-device selection command is to be executed for this writer, the
device is likely damaged. Therefore, never use this command.
■ When disabling the writing
When disabling the writing, check the following points.
(1)Check that the device is mounted correctly on the socket.(pin bending,
connecting failure).
(2)Check that the erase check result is no problem.
(3)Check that the adapter type is identical to the device name.
(4)Check that the writing mode is set correctly.
(5)Check that the data is correctly transferred to the ROM writer.
(6)Recheck the check points (1),(2) and (3) provided on the above
paragraph of ìCautions on Handling the ROM writerî.
When the writing is disabled even after the above check points are
confirmed and the device is replaced with another one, contact the
nearest semiconductor design center.
(See the attached sales office table.)