MX29F200T/B
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.
POWER SUPPLY DECOUPLING
In order to reduce power switching effect, each device
should have a 0.1uF ceramic capacitor connected
between its VCC and GND.
SECTOR PROTECTION WITH 12V SYSTEM
SECTOR PROTECTION WITHOUT 12V
SYSTEM
TheMX29F200T/Bfeatureshardwaresectorprotection.
This feature will disable both program and erase
operations for these sectors protected. To activate this
mode, the programming equipment must force VID on
address pin A9 and control pin OE, (suggest VID = 12V)
A6 = VIL and CE = VIL.(see Table 2) Programming of
the protection circuitry begins on the falling edge of the
WE pulse and is terminated on the rising edge. Please
refer to sector protect algorithm and waveform.
The MX29F200T/B also feature a hardware sector
protectionmethodinasystemwithout12Vpowersuppply.
The programming equipment do not need to supply 12
volts to protect sectors. The details are shown in sector
protectalgorithmandwaveform.
CHIP UNPROTECT WITHOUT 12V SYSTEM
To verify programming of the protection circuitry, the
programming equipment must force VID on address pin
A9(withCEandOEatVILandWEatVIH. WhenA1=1,
it will produce a logical "1" code at device output Q0 for
a protected sector. Otherwise the device will produce
00H for the unprotected sector. In this mode, the
addresses,except for A1, are in "don't care" state.
Address locations with A1 = VIL are reserved to read
manufacturer and device codes.(Read Silicon ID)
The MX29F200T/B also feature a hardware chip
unprotection method in a system without 12V power
supply. The programming equipment do not need to
supply 12 volts to unprotect all sectors. The details are
shown in chip unprotect algorithm and waveform.
POWER-UP SEQUENCE
It is also possible to determine if the sector is protected
in the system by writing a Read Silicon ID command.
PerformingareadoperationwithA1=VIH,itwillproduce
a logical "1" at Q0 for the protected sector.
TheMX29F200T/BpowersupintheReadonlymode. In
addition, thememorycontentsmayonlybealteredafter
successful completion of the predefined command
sequences.
CHIP UNPROTECT WITH 12V SYSTEM
The MX29F200T/B also features the chip unprotect
mode, so that all sectors are unprotected after chip
unprotect is completed to incorporate any changes in
thecode.Itisrecommendedtoprotectallsectorsbefore
activating chip unprotect mode.
To activate this mode, the programming equipment
must force VID on control pin OE and address pin A9.
The CE pins must be set at VIL. Pins A6 must be set to
VIH.(seeTable2) Refertochipunprotect algorithmand
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
P/N:PM0549
REV. 1.3 , DEC. 24, 2001
14
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