M29W128GH, M29W128GL
Hardware protection
4
Hardware protection
The M29W128GH and M29W128GL feature a V /WP pin that protects the highest or
PP
lowest block. Refer to Section 2: Signal descriptions for a detailed description of the signal.
5
Software protection
The M29W128GH and M29W128GL have three different software protection modes:
●
●
●
Volatile protection
Non-volatile protection
Password protection
On first use all parts default to operate in non-volatile protection mode and the customer is
free to activate the non-volatile or the password protection mode.
The desired protection mode is activated by setting either the one-time programmable Non-
volatile Protection Mode Lock bit, or the Password Protection Mode Lock bit of the Lock
Register (see Section 7.1: Lock Register). Programming the Non-volatile Protection Mode
Lock bit or the Password Protection Mode Lock bit, to ‘0’ will permanently activate the Non-
volatile or the Password Protection mode, respectively. These two bits are one-time
programmable and non-volatile: once the protection mode has been programmed, it cannot
be changed and the device will permanently operate in the selected protection mode. It is
recommended to activate the desired software protection mode when first programming the
device.
The Non-volatile and Password Protection modes both provide non-volatile protection.
Volatilely protected blocks and non-volatilely protected blocks can co-exist within the
memory array. However, the volatile protection only control the protection scheme for blocks
that are not protected using the non-volatile or password protection.
If the user attempts to program or erase a protected block, the device ignores the command
and returns to read mode.
The device is shipped with all blocks unprotected. The block protection status can be read
either by performing a read electronic signature (see Table 6 and Table 7) or by issuing an
Auto Select command (see Table 19: Block protection status).
For the lowest and highest blocks, an even higher level of block protection can be achieved
by locking the blocks using the non-volatile protection and then by holding the V /WP pin
PP
Low.
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NUMONYX [ NUMONYX B.V ]
