Hardware manual

Rev. 3.0, 09/98, page 261 of 361
14.3.2 Notes on Writing
(1) Write with the specified voltages and timing. The programming voltage (V
PP
) is 12.5V.
Caution: Applied voltages in excess of the specified values can permanently destroy the chip. Be
particularly careful about the PROM writer’s overshoot characteristics.
If the PROM writer is set to HN27C101 specifications, V
PP
will be 12.5V.
(2) Before writing data, check that the socket adapter and chip are correctly mounted in the
PROM writer. Overcurrent damage to the chip can result if the index marks on the PROM
writer, socket adapter, and chip are not correctly aligned.
(3) Don’t touch the socket adapter or chip while writing. Touching either of these can cause
contact faults and write errors.
(4) Page programming is not supported. Do not select page programming mode.
(5) The H8/338 PROM size is 48K bytes. The H8/337 PROM size is 32K bytes. Set the
address range to H'0000 to H'BFFF for the H8/338, and to H'0000 to H'7FFF for the H8/337.
When programming, specify H'FF data for unused address areas (H'C000 to H'1FFFF in the
H8/338, H'8000 to H'1FFFF in the H8/337).