Extended memory block
M29W128GH, M29W128GL
C.2
Customer lockable extended memory block
A device where the extended memory block is customer lockable is delivered with the DQ7
bit set to ‘0’ and the extended memory block unprotected. It is up to the customer to program
and protect the extended memory block but care must be taken because the protection of
the extended memory block is not reversible.
If the device has not been shipped with the extended memory block factory protected, the
block can be protected by setting the Extended Memory Block Protection bit, DQ0, to ‘0’.
However, this bit is one-time programmable and once protected the extended memory block
cannot be unprotected.
Once the extended memory block is programmed, the Exit Extended Memory Block
command must be issued to exit the Extended Memory Block mode and return the device to
Read mode.
Table 41. Extended memory block address and data
Address(1)
Data
x 8
x 16
Factory locked
Customer lockable
000000h-0000FFh 000000h-00007Fh Security identification number Determined by customer
1. See Table 34: Block addresses.
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NUMONYX [ NUMONYX B.V ]
