114
6.3.2
Programming Precautions
•
Use the specified programming voltage and timing.
The programming voltage in PROM mode (V
PP
) is 12.5 V. Use of a higher voltage can
permanently damage the chip. Be especially careful with respect to PROM programmer
overshoot.
Setting the PROM programmer to Hitachi specifications for the HN27C101 will result in
correct V
PP
of 12.5 V.
•
Make sure the index marks on the PROM programmer socket, socket adapter, and chip are
properly aligned. If they are not, the chip may be destroyed by excessive current flow. Before
programming, be sure that the chip is properly mounted in the PROM programmer.
•
Avoid touching the socket adapter or chip while programming, since this may cause contact
faults and write errors.
•
Select the programming mode carefully. The chip cannot be programmed in page
programming mode.
•
When programming with a PROM programmer, be sure to specify addresses from H'0000 to
H'EDFF. If address H'EE00 and higher addresses are programmed by mistake, it may become
impossible to program the PROM or verify the programmed data. When programming, assign
H'FF data to the address area from H'EE00 to H'1FFFF.