S71PL254 datasheet(53/196 Pages) SPANSION

53 / 196 page

August 12, 2004 S29PL127J_064J_032J_MCP_00_A3

S29PL127J/S29PL064J/S29PL032J for MCP

Advance

I n f o rmatio n

Sector Protection

The PL127J, PL064J, and PL032J features several levels of sector protection,

which can disable both the program and erase operations in certain sectors or

sector groups.

Sector Protection Schemes

Password Sector Protection

A highly sophisticated protection method that requires a password before

changes to certain sectors or sector groups are permitted

WP# Hardware Protection

A write protect pin that can prevent program or erase operations in sectors SA1-

133, SA1-134, SA2-0 and SA2-1.

The WP# Hardware Protection feature is always available, independent of the

software managed protection method chosen.

Selecting a Sector Protection Mode

All parts default to operate in the Persistent Sector Protection mode. The cus-

tomer must then choose if the Persistent or Password Protection method is most

desirable. There are two one-time programmable non-volatile bits that define

which sector protection method will be used. If the Persistent Sector Protection

method is desired, programming the Persistent Sector Protection Mode Locking

Bit permanently sets the device to the Persistent Sector Protection mode. If the

Password Sector Protection method is desired, programming the Password Mode

Locking Bit permanently sets the device to the Password Sector Protection mode.

It is not possible to switch between the two protection modes once a locking bit

has been set. One of the two modes must be selected when the device is first

programmed. This prevents a program or virus from later setting the Password

Mode Locking Bit, which would cause an unexpected shift from the default Per-

sistent Sector Protection Mode into the Password Protection Mode.

The device is shipped with all sectors unprotected. Optional Spansion program-

ming services enable programming and protecting sectors at the factory prior to

shipping the device. Contact your local sales office for details.

Table 12. Sector Protection Schemes

DYB

PPB

PPB Lock

Sector State

Unprotected—PPB and DYB are changeable

Unprotected—PPB not changeable, DYB is changeable

Protected—PPB and DYB are changeable

Protected—PPB not changeable, DYB is changeable

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