m29dw641f STMicroelectronics, m29dw641f Datasheet - Page 21

• Manufacturer Part Number: m29dw641f
• Description: 64 Mbit 4mb X16, Multiple Bank, Boot Block 3v Supply Flash Memory
• Manufacturer: STMicroelectronics

M29DW641F
5
5.1
5.1.1
Software Protection
The M29DW641F has two different Software Protection modes: the Standard and Password
Protection modes.
On first use all parts default to the Standard Protection mode and the customer is free to
activate the Standard or the Password Protection mode.
The desired protection mode is activated by setting one of two one-time programmable bits,
the Standard Protection mode Lock bit or the Password Protection mode Lock bit.
Programming the Standard or the Password Protection mode Lock bit to ‘1’ will permanently
activate the Standard 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 device is shipped with all blocks unprotected. The Block Protection status can be read
by issuing the Auto Select command (see
The Standard and Password Protection modes offer two levels of protection, a Block
Lock/Unlock protection and a Non-volatile Protection.
For the four outermost parameter 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
Standard Protection mode
Block Lock/Unlock Protection
It is a flexible mechanism to protect/unprotect a block or a group of blocks from Program or
Erase Operations.
A volatile Lock bit is assigned to each block or group of blocks. When the lock bit is set to ‘1’
the associated block or group of blocks is protected from Program/Erase Operations, when
the Lock bit is set to ‘0’ the associated block or group of blocks is unprotected and can be
programmed or erased.
The Lock bits can be set (‘1’) and cleared (‘0’) individually as often as required by issuing a
Set Lock bit command and Clear Lock bit command, respectively.
After a Power-up or Hardware Reset, all the Lock bits are cleared to ‘0’ (block unlocked).
The device is shipped with all the Lock bits set to ‘0’.
PP
/WP pin Low.
Table 7: Block Protection
status).
Software Protection
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