MYX28F00AM29EWH Datasheet, PDF (27/51 Pages) –

15.5
15.6
16
1Gb Parallel NOR Flash
MYX28F00AM29EWH*
*Advanced information. Subject to change without notice.
To achieve the best protection, the PROGRAM NONVOLATILE PROTECTION LOCK BIT command should be
executed early in the boot code, and the boot code should be protected by holding V_PP/WP# LOW.
Nonvolatile protection bits and volatile protection bits have the same function when V_PP/WP# is HIGH or when
V_PP/WP# is at the voltage for program acceleration (V_PPH).
Password Protection Mode
The password protection mode provides a higher level of security than the nonvolatile protection mode by
requiring a 64-bit password to unlock the nonvolatile protection bit lock bit. In addition to this password
requirement, the nonvolatile protection bit lock bit is set to 0 after power-up and reset to maintain the device in
password protection mode.
Executing the UNLOCK PASSWORD command by entering the correct password clears the nonvolatile
protection bit lock bit, enabling the block nonvolatile protection bits to be modified. If the password provided is
incorrect, the nonvolatile protection bit lock bit remains locked, and the state of the nonvolatile protection bits
cannot be modified.
Note: There is no means to verify the password after password protection mode is enabled. If the password is
lost after enabling the password protection mode, there is no way to clear the nonvolatile protection bit lock bit.
Password Access
Password access is a security enhancement that protects information stored in the main array blocks by
preventing content alteration or reads until a valid 64-bit password is received. Password access may be
combined with nonvolatile and/or volatile protection to create a multi-tiered solution.
Common Flash Interface
The common Flash interface (CFI) is a JEDEC-approved, standardized data structure that can be read from
the Flash memory device. It allows a system’s software to query the device to determine various electrical and
timing parameters, density information, and functions supported by the memory. The system can interface
easily with the device, enabling the software to upgrade itself when necessary.
When the READ CFI command is issued, the device enters CFI query mode and the data structure is read from
memory. The query data is always presented on the lowest order data outputs (DQ[7:0]), and the other data
outputs (DQ[15:8]) are set to 0.
MYX28F00AM29EWH
Revision 1.0 - 11/14/2014
27
Form #: CSI-D-685 Document 003