MX29F040
SECTOR PROTECTION WITH 12V SYSTEM
The MX29F040 features sector protection. This feature
will disable both program and erase operations for these
sectors protected. To activate this mode, the program-
ming 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 cir-
cuitry begins on the falling edge of the WE or CE, which-
ever happens later pulse and is terminated on the rising
edge. Please refer to sector protect algorithm and wave-
form.
To verify programming of the protection circuitry, the pro-
gramming equipment must force VID on address pin A9
( with CE and OE at VIL and WE at VIH). When A1=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 don't care. Address locations with A1
= VIL are reserved to read manufacturer and device codes.
(Read Silicon ID)
It is also possible to determine if the sector is protected
in the system by writing a Read Silicon ID command.
Performing a read operation with A1=VIH, it will produce
a logical "1" at Q0 for the protected sector.
is noted that all sectors are unprotected after the chip
unprotect algorithm is completed.
POWER-UP SEQUENCE
The MX29F040 powers up in the Read only mode. In
addition, the memory contents may only be altered after
successful completion of the predefined command se-
quences.
SECTOR PROTECTION WITHOUT 12V SYS-
TEM
The MX29F040 also feature a sector protection method
in a system without 12V power supply. The programming
equipment do not need to supply 12 volts to protect sec-
tors. The details are shown in sector protect algorithm
and waveform.
CHIP UNPROTECT WITHOUT 12V SYSTEM
The MX29F040 also feature a 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 algo-
rithm and waveform.
CHIP UNPROTECT WITH 12V SYSTEM
The MX29F040 also features the chip unprotect mode,
so that all sectors are unprotected after chip unprotect
is completed to incorporate any changes in the code. It
is recommended to protect all sectors before 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.(see
Table 2) Refer to chip unprotect algorithm and wave-
form for the chip unprotect algorithm. The unprotection
mechanism begins on the falling edge of the WE or CE,
whichever happens later, 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.
Performing a read operation with A1=VIH, it will produce
00H at data outputs(Q0-Q7) for an unprotected sector. It
P/N:PM0538
REV. 2.3, DEC. 10, 2004
12
MCNIX [ MACRONIX INTERNATIONAL ]
