MX29LA129M H/L
It is also possible to determine if the group is protected
in the system by writing a Read Silicon ID command.
Performing a read operation with A2=VIH, it will produce
a logical "1" at Q0 for the protected sector.
last protected or unprotect using the method described in
"Sector/Sector Group Protection and Chip Unprotect".
Note that the WP# pin must not be left floating or uncon-
nected; inconsistent behavior of the device may result.
CHIP UNPROTECT OPERATION
TEMPORARY SECTOR GROUP UNPROTECT
OPERATION
The MX29LA129M H/L 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.
This feature allows temporary unprotect of previously
protected sector to change data in-system.The Tempo-
rary Sector Unprotect mode is activated by setting the
RESET# pin toVID(11.5V-12.5V). During this mode, for-
merly protected sectors can be programmed or erased
as unprotect sector. Once VID is remove from the RE-
SET# pin, all the previously protected sectors are pro-
tected again.
To activate this mode, the programming equipment must
force VID on control pin OE# and address pin A10. The
CEx pins must be set at VIL. Pins A7 must be set to
VIH.(seeTable 2) Refer to chip unprotect algorithm and
waveform for the chip unprotect algorithm. The unprotect
mechanism begins on the falling edge of the WE# pulse
and is terminated on the rising edge.
SILICON ID READ OPERATION
MX29LA129M H/L also provides another method.Which
requires VID on the RESET# only. This method can be
implemented either in-system or via programming equip-
ment. This method uses standard microprocessor bus
cycle timing.
Flash memories are intended for use in applications where
the local CPU alters memory contents. As such, manu-
facturer and device codes must be accessible while the
device resides in the target system. PROM program-
mers typically access signature codes by raising A10 to
a high voltage. However, multiplexing high voltage onto
address lines is not generally desired system design prac-
tice.
It is also possible to determine if the chip is unprotect in
the system by writing the Read Silicon ID command.
Performing a read operation with A2=VIH, it will produce
00H at data outputs (Q0-Q7) for an unprotect sector.It is
noted that all sectors are unprotected after the chip
unprotect algorithm is completed.
MX29LA129M H/L provides hardware method to access
the silicon ID read operation.Which method requiresVID
on A10 pin, VIL on CEx, OE#, A7, and A2 pins. Which
applyVIL on A1 pin, the device will output MXIC's manu-
facture code of which applyVIH on A1 pin, the device will
output MX29LA129M H/L device code.
WRITE PROTECT (WP#)
The write protect function provides a hardware method
to protect all sectors without using VID.
VERIFY SECTOR GROUP PROTECT STATUS
OPERATION
If the system asserts VIL on the WP# pin, the device
disables program and erase functions in all sectors inde-
pendently of whether those sectors were protected or
unprotect using the method described in Sector/Sector
Group Protection and Chip Unprotect".
MX29LA129M H/L provides hardware method for sector
group protect status verify. Which method requires VID
on A10 pin, VIH on WE# and A2 pins, VIL on CEx, OE#,
A7, and A1 pins, and sector address on A16 to A23 pins.
Which the identified sector is protected, the device will
output 01H.Which the identified sector is not protect, the
device will output 00H.
If the system asserts VIH on the WP# pin, the device
reverts to whether the sectors were last set to be pro-
tected or unprotect. That is, sector protection or
unprotection for the sectors depends on whether they were
P/N:PM1171
REV. 1.0, FEB. 27, 2006
17
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