S25FL256SDPMHVF01 View Datasheet(PDF) - Cypress Semiconductor
Part Name
Description
Manufacturer
S25FL256SDPMHVF01
Cypress Semiconductor
S25FL256SDPMHVF01 Datasheet PDF : 144 Pages
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S25FL128S, S25FL256S
8.4.1
ASP Register
The ASP register is used to permanently configure the behavior of Advanced Sector Protection (ASP) features. See Table 7.17,
ASP Register (ASPR) on page 54.
As shipped from the factory, all devices default ASP to the Persistent Protection mode, with all sectors unprotected, when power is
applied. The device programmer or host system must then choose which sector protection method to use. Programming either of
the, one-time programmable, Protection Mode Lock Bits, locks the part permanently in the selected mode:
ASPR[2:1] = 11 = No ASP mode selected, Persistent Protection Mode is the default.
ASPR[2:1] = 10 = Persistent Protection Mode permanently selected.
ASPR[2:1] = 01 = Password Protection Mode permanently selected.
ASPR[2:1] = 00 = Illegal condition, attempting to program both bits to zero results in a programming failure.
ASP register programming rules:
If the password mode is chosen, the password must be programmed prior to setting the Protection Mode Lock Bits.
Once the Protection Mode is selected, the Protection Mode Lock Bits are permanently protected from programming and no
further changes to the ASP register is allowed.
The programming time of the ASP Register is the same as the typical page programming time. The system can determine the status
of the ASP register programming operation by reading the WIP bit in the Status Register. See Status Register 1 (SR1) on page 48
for information on WIP.
After selecting a sector protection method, each sector can operate in each of the following states:
Dynamically Locked — A sector is protected and can be changed by a simple command.
Persistently Locked — A sector is protected and cannot be changed if its PPB Bit is 0.
Unlocked — The sector is unprotected and can be changed by a simple command.
8.4.2
Persistent Protection Bits
The Persistent Protection Bits (PPB) are located in a separate nonvolatile flash array. One of the PPB bits is related 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. The PPB have the same program and erase endurance as the main flash memory array. Preprogramming and
verification prior to erasure are handled by the device.
Programming a PPB bit requires the typical page programming time. Erasing all the PPBs requires typical sector erase time. During
PPB bit programming and PPB bit erasing, status is available by reading the Status register. Reading of a PPB bit requires the initial
access time of the device.
Notes:
1. Each PPB is individually programmed to 0 and all are erased to 1 in parallel.
2. If the PPB Lock bit is 0, the PPB Program or PPB Erase command does not execute and fails without programming or erasing the PPB.
3. The state of the PPB for a given sector can be verified by using the PPB Read command.
8.4.3
Dynamic Protection Bits
Dynamic Protection Bits are volatile and unique for each sector and can be individually modified. DYB only control the protection for
sectors that have their PPB set to 1. By issuing the DYB Write command, a DYB is cleared to 0 or set to 1, thus placing each sector
in the protected or unprotected state respectively. 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 DYBs can be set or cleared as often as needed
as they are volatile bits.
Document Number: 001-98283 Rev. *I
Page 60 of 144
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