S25FS256S datasheet(80/154 Pages) SPANSION

80 / 154 page

S25FS-S Family

S25FS-S_00_04 November 6, 2013

Data

Sheet

(Pre limin ar y)

Figure 9.2 Advanced Sector Protection Overview

The Persistent Protection method sets the PPB Lock bit to 1 during POR, or hardware reset so that the PPB

bits are unprotected by a device reset. There is a command to clear the PPB Lock bit to 0 to protect the PPB.

There is no command in the Persistent Protection method to set the PPB Lock bit to 1, therefore the PPB

Lock bit will remain at 0 until the next power-off or hardware reset. The Persistent Protection method allows

boot code the option of changing sector protection by programming or erasing the PPB, then protecting the

PPB from further change for the remainder of normal system operation by clearing the PPB Lock bit to 0. This

is sometimes called Boot-code controlled sector protection.

Power On / Reset

ASPR[2]=0

ASPR[1]=0

PPBLOCK = 0

PPB Bits Locked

PPBLOCK = 1

PPB Bits Erasable

ASPR Bits Locked

ASPR Bits Are

Programmable

and Programmable

Password Unlock

PPBLOCK = 1

PPB Bits Erasable

and Programmable

Password Protection

Persistent Protection

Default

Persistent Protection

PPB Lock Bit Write

PPBLOCK = 0

PPB Bits Locked

Yes

Password Protection

Mode

protects

the

Persistent Protection

Mode does not

Default Mode allows

protect the PPB after

power up. The bits may

be changed. A PPB

Lock Bit write command

protects the PPB bits

until the next power-off

or reset.

PPB after power up.

A password unlock

command will enable

changes to PPB. A PPB

Lock Bit write command

turns protection back on.

ASPR to be programmed

to permanently select

the Protection mode.

The default mode otherwise

acts the same as the

Persistent Protection Mode.

After one of the protection

modes is selected, ASPR

is no longer programmable,

making the selected protection

mode permanent.

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