mx25l3255d Macronix International Co., mx25l3255d Datasheet - Page 10

• Manufacturer Part Number: mx25l3255d
• Description: Security Serial Flash
• Manufacturer: Macronix International Co.

P/N: PM1431
DATA PROTECTION
MX25L3255D is designed to offer protection against accidental erasure or programming caused by spurious system
level signals that may exist during power transition. During power up the device automatically resets the state ma-
chine in the standby mode. In addition, with its control register architecture, alteration of the memory contents only
occurs after successful completion of specific command sequences. The device also incorporates several features
to prevent inadvertent write cycles resulting from VCC power-up and power-down transition or system noise.
• Valid command length checking: The command length will be checked whether it is at byte base and completed
• Write Enable (WREN) command: WREN command is required to set the Write Enable Latch bit (WEL) before
•
•
I. Block Write Lock protection
on byte boundary.
other command to change data. The WEL bit will return to reset stage under following situation:
- Power-up
- Write Disable (WRDI) command completion
- Page Program (PP) command completion
- Continuously Program mode (CP) instruction completion
- Sector Erase (SE) command completion
- Block Erase (BE) command completion
- Chip Erase (CE) command completion
Deep Power Down Mode: By entering deep power down mode, the flash device also is under protected from
writing all commands except Release from deep power down mode command (RDP) and Read Electronic Sig-
nature command (RES).
Advanced Security Features: there are some protection and securuity features which protect content from inad-
vertent write and hostile access.
- The Software Protected Mode (SPM) use A23-A16 address bits to allow a block (64K Byte) of memory to be
protected as read only through the Block Write Lock protection command (BLOCKP). This feature allows user to
unprotect the entice chip through the chip unprotect command (UNLOCK).
- The Hardware Protected Mode (HPM) use WP#/SIO2 to protect the Block.
If WP#/SIO2=VIL (input Low), all blocks of memory to be protected as read only.
If WP#/SIO2=VIH (input High), all blocks depends on whether they were last Lock or Unlock. If the system goes
into four I/O read mode, the feature of HPM will be disabled.
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MX25L3255D
REV. 0.03, MAR. 13, 2009