MX29LV800T/B
CHIP UNPROTECT
The MX29LV800T/B also features the chip unprotect
mode, so that all sectors are unprotected after chip
unprotectiscompletedtoincorporateanychangesinthe
code. It is recommended to protect all sectors before
activating chip unprotect mode.
Toactivatethismode,theprogrammingequipmentmust
forceVIDoncontrolpinOEandaddresspinA9. TheCE
pins must be set at VIL. Pins A6 must be set to VIH.
Refer to chip unprotect algorithm and waveform for the
chip unprotect algorithm. The unprotection mechanism
begins on the falling edge of the WE pulse and is
terminated on the rising edge.
It is also possible to determine if the chip is unprotected
in the system by writing the Read Silicon ID command.
PerformingareadoperationwithA1=VIH,itwillproduce
00H at data outputs(Q0-Q7) for an unprotected sector.
It is noted that all sectors are unprotected after the chip
unprotect algorithm is completed.
P/N:PM0709
REV. 1.3, JAN. 24, 2002
18
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