Hitachi H8/500 Series User Manual

17.3.2 Notes on Writing
1. Write with the specified voltages and timing. The programming voltage (Vpp) in the
PROM mode is 12.5V.
Caution: Applied voltages in excess of the specified values can permanently destroy to the chip.
Be particularly careful about the PROM writer’s overshoot characteristics.
If the PROM writer is set to Intel specifications or Hitachi HN27256 or HN27C256 specifications,
Vpp 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.
GND
OE
CE
Write
Verify
Address
Data Input data Output data
Vpp Vpp
Vcc
Vcc
Vcc
tAS
tDS
tVPS
tVCS
tDH
tPW tOES tOE
tOPW
tAH
tDF
Figure 17-5 PROM Write/Verify Timing
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Hitachi H8/500 Series Specifications

General

Brand	Hitachi
Model	H8/500 Series
Category	Computer Hardware
Language	English