MX25L12845E
DATA PROTECTION
MX25L12845E is designed to offer protection against accidental erasure or programming caused by spurious sys-
tem level signals that may exist during power transition. During power up the device automatically resets the state
machine 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 fea-
tures 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
on byte boundary.
• Write Enable (WREN) command: WREN command is required to set the Write Enable Latch bit (WEL) before
other command to change data. The WEL bit will return to reset stage under following situation:
- Power-up
- Write Disable (WRDI) command completion
- Write Status Register (WRSR) command completion
- Page Program (PP, 4PP) command completion
- Continuously Program mode (CP) instruction completion
- Sector Erase (SE) command completion
- Block Erase (BE, BE32K) command completion
- Chip Erase (CE) command completion
- Single Block Lock/Unlock (SBLK/SBULK) instruction completion
- Gang Block Lock/Unlock (GBLK/GBULK) instruction 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).
I. Block lock protection
- The Software Protected Mode (SPM) uses (BP3, BP2, BP1, BP0) bits to allow part of memory to be protected
as read only. The protected area definition is shown as table of "Protected Area Sizes", the protected areas are
more flexible which may protect various area by setting value of BP0-BP3 bits. Please refer to table of "Protect-
ed Area Sizes".
- The Hardware Protected Mode (HPM) use WP#/SIO2 to protect the (BP3, BP2, BP1, BP0) bits and SRWD bit.
If the system goes into four I/O mode, the feature of HPM will be disabled.
- MX25L12845E provide individual block (or sector) write protect & unprotect. User may enter the mode with
WPSEL command and conduct individual block (or sector) write protect with SBLK instruction, or SBULK for
individual block (or sector) unprotect. Under the mode, user may conduct whole chip (all blocks) protect with
GBLK instruction and unlock the whole chip with GBULK instruction.
P/N: PM1428
REV. 0.06, MAR. 05, 2009
10
Macronix [ MACRONIX INTERNATIONAL ]
