S29GL01GS datasheet(20/106 Pages) SPANSION

20 / 106 page

GL-S MirrorBit® Family

S29GL_128S_01GS_00_08 October 9, 2013

Da ta

Sh e e t

There is no command in the Persistent Protection method to set the PPB Lock bit 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. This is sometimes

called Boot-code controlled sector protection.

The Password method clears the PPB Lock bit to 0 during POR or Hardware Reset to protect the PPB. A 64-

bit password may be permanently programmed and hidden for the password method. A command can be

used to provide a password for comparison with the hidden password. If the password matches the PPB Lock

bit is set to 1 to unprotect the PPB. A command can be used to clear the PPB Lock bit to 0.

The selection of the PPB Lock management method is made by programming OTP bits in the Lock Register

so as to permanently select the method used.

The Lock Register also contains OTP bits, for protecting the SSR.

The PPB bits are erased so that all main flash array sectors are unprotected when shipped from Spansion.

The Secured Silicon Region can be factory protected or left unprotected depending on the ordering option

(model) ordered.

3.4.3

PPB Lock

The Persistent Protection Bit Lock is a volatile bit for protecting all PPB bits. When cleared to 0, it locks all

PPBs and when set to 1, it allows the PPBs to be changed. There is only one PPB Lock Bit per device.

The PPB Lock command is used to clear the bit to 0. The PPB Lock Bit must be cleared to 0 only after all the

PPBs are configured to the desired settings.

In Persistent Protection mode, the PPB Lock is set to 1 during POR or a hardware reset. When cleared, no

software command sequence can set the PPB Lock, only another hardware reset or power-up can set the

PPB Lock bit.

In the Password Protection mode, the PPB Lock is cleared to 0 during POR or a hardware reset. The PPB

Lock can only set to 1 by the Password Unlock command sequence. The PPB Lock can be cleared by the

PPB Lock Bit Clear command.

3.4.4

Persistent Protection Bits (PPB)

The Persistent Protection Bits (PPB) are located in a separate nonvolatile flash array. One of the PPB bits is

assigned to each sector. When a PPB is 0 its related sector is protected from program and erase operations.

The PPB are programmed individually but must be erased as a group, similar to the way individual words may

be programmed in the main array but an entire sector must be erased at the same time. Preprogramming and

verification prior to erasure are handled by the EAC.

Programming a PPB bit requires the typical word programming time. During a PPB bit programming operation

or PPB bit erasing, Data polling Status DQ6 Toggle Bit I will toggle until the operation is complete. Erasing all

the PPBs requires typical sector erase time.

If the PPB Lock is 0, the PPB Program or erase commands do not execute and time-out without programming

or erasing the PPB.

The protection state of a PPB for a given sector can be verified by executing a PPB Status Read command

when entered in the PPB ASO.

3.4.5

Dynamic Protection Bits (DYB)

Dynamic Protection Bits are volatile and unique for each sector and can be individually modified. DYBs only

control protection for sectors that have their PPBs erased. By issuing the DYB Set or Clear command

sequences, the DYB are set to 0 or cleared to 1, thus placing each sector in the protected or unprotected

state respectively, if the PPB for the Sector is 1. This feature allows software to easily protect sectors against

inadvertent changes, yet does not prevent the easy removal of protection when changes are needed.

The DYB can be set to 0 or cleared to 1 as often as needed.

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