HY29F400 Datasheet, PDF (19/40 Pages) Hynix Semiconductor – 4 Megabit (512Kx8/256Kx16) 5 Volt-only Flash Memory

Write Pulse “Glitch” Protection
Noise pulses of less than 5 ns (typical) on OE#,
CE# or WE# do not initiate a write cycle.
Logical Inhibit
Write cycles are inhibited by asserting any one of
the following conditions: OE# = V_IL , CE# = V_IH, or
WE# = V_IH. To initiate a write cycle, CE# and WE#
must be a logical zero while OE# is a logical one.
HY29F400
Power-Up Write Inhibit
If WE# = CE# = V_IL and OE# = V_IH during power
up, the device does not accept commands on the
rising edge of WE#. The internal state machine is
automatically reset to the Read mode on power-
up.
Sector Protection
Additional data protection is provided by the
HY29F400’s sector protect feature, described pre-
viously, which can be used to protect sensitive
areas of the Flash array from accidental or unau-
thorized attempts to alter the data.
Rev. 5.2/May 01
19