S70GL01GN00 Datasheet, PDF (34/83 Pages) SPANSION – 3.0 Volt-only Page Mode Flash Memory featuring 110 nm MirrorBit™ Process Technology

Advance Information
sequence execution, the DQ6 Toggle Bit I toggles until the programming of the
PPB bit or erasing of all PPB bits is completed which indicates programming and
erasing status. Erasing all of the PPB bits at once requires typical sector erase
time. During the erasing of all PPB bits, the DQ3 Sector Erase Timer bit outputs
a 1 to indicate the erasure of all PPB bits are in progress. When the erasure of all
PPB bits is completed, the DQ3 Sector Erase Timer bit outputs a 0 to indicate that
all PPB bits are erased. Reading the PPB Status bit requires the initial access time
of the device.
Persistent Protection Bit Lock (PPB Lock Bit)
A global volatile bit. When set to the freeze state, the PPB bits cannot be changed.
When cleared to the unfreeze state, the PPB bits are changeable. There is only
one PPB Lock Bit per device. The PPB Lock Bit is cleared to the unfreeze state after
power-up or hardware reset. There is no command sequence to unlock or un-
freeze state the PPB Lock Bit.
Configuring the PPB Lock Bit to the freeze state requires approximately 100ns.
Reading the PPB Lock Status bit requires the initial access time of the device.
DYB Bit
Unprotect
Unprotect
Unprotect
Unprotect
Protect
Protect
Protect
Protect
Table 5. Sector Protection Schemes
Protection States
PPB Bit
PPB Lock Bit
Sector State
Unprotect
Unfreeze
Unprotected – PPB and DYB are changeable
Unprotect
Freeze
Unprotected – PPB not changeable, DYB is changeable
Protect
Unfreeze
Protected – PPB and DYB are changeable
Protect
Freeze
Protected – PPB not changeable, DYB is changeable
Unprotect
Unfreeze
Protected – PPB and DYB are changeable
Unprotect
Freeze
Protected – PPB not changeable, DYB is changeable
Protect
Unfreeze
Protected – PPB and DYB are changeable
Protect
Freeze
Protected – PPB not changeable, DYB is changeable
Table 5 contains all possible combinations of the DYB bit, PPB bit, and PPB Lock
Bit relating to the status of the sector. In summary, if the PPB bit is set, and the
PPB Lock Bit is set, the sector is protected and the protection cannot be removed
until the next power cycle or hardware reset clears the PPB Lock Bit to unfreeze
state. If the PPB bit is cleared, the sector can be dynamically locked or unlocked.
The DYB bit then controls whether or not the sector is protected or unprotected.
If the user attempts to program or erase a protected sector, the device ignores
the command and returns to read mode. A program command to a protected sec-
tor enables status polling for approximately 1 µs before the device returns to read
mode without having modified the contents of the protected sector. An erase
command to a protected sector enables status polling for approximately 50 µs
after which the device returns to read mode without having erased the protected
sector. The programming of the DYB bit, PPB bit, and PPB Lock Bit for a given sec-
tor can be verified by writing a DYB Status Read, PPB Status Read, and PPB Lock
Status Read commands to the device.
The Autoselect Sector Protection Verification outputs the OR function of the DYB
bit and PPB bit per sector basis. When the OR function of the DYB bit and PPB bit
is a 1, the sector is either protected by DYB or PPB or both. When the OR function
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S70GL01GN00 MirrorBit^TM Flash
S70GL01GN00_00_A1 June 1, 2005