S25FL256SDPNFVB03 View Datasheet(PDF) - Cypress Semiconductor

Part Name

Description

Manufacturer

S25FL256SDPNFVB03

128 Mbit (16 Mbyte), 256 Mbit (32 Mbyte) 3.0V SPI Flash Memory

Cypress Semiconductor 

S25FL128S, S25FL256S

8.4 Advanced Sector Protection

Advanced Sector Protection (ASP) is the name used for a set of independent hardware and software methods used to disable or

enable programming or erase operations, individually, in any or all sectors. An overview of these methods is shown in Figure 8.1,

Advanced Sector Protection Overview on page 59.

Block Protection and ASP protection settings for each sector are logically OR’d to define the protection for each sector, i.e. if either

mechanism is protecting a sector the sector cannot be programmed or erased. Refer to Block Protection on page 58 for full details of

the BP2-0 bits.

Figure 8.1 Advanced Sector Protection Overview

6) Password Method requires a

password to set PPB Lock to ‘1’

to enable program or erase of

PPB bits

Memory Array

Sector 0

Sector 1

Sector 2

ASP Register

One Time Programmable

Password Method Persistent Method

(ASPR[2]=0)

(ASPR[1]=0)

64-bit Password

(One Time Protect)

7) Persistent Method only allows

PPB Lock to be cleared to ‘0’ to

prevent program or erase of PPB

bits. Power off or hardware reset

required to set PPB Lock to ‘1’

PBB Lock Bit

4) PPB Lock bit is volatile and

defaults to ‘1’ (persistent mode), or

‘0’ (password mode) upon reset

‘0’ = PPBs locked

Persistent

Protection Bits

(PPB)

PPB 0

PPB 1

PPB 2

‘1’=PPBs unlocked

5) PPB Lock = ‘0’ locks all PPBs

to their current state

Dynamic

Protection Bits

(DYB)

DYB 0

DYB 1

DYB 2

Sector N -2

Sector N -1

Sector N

1) N = Highest Address Sector,

a sector is protected if its PPB =’0’

or its DYB = ‘0’

PPB N-2

PPB N-1

PPB N

DYB N-2

DYB N-1

DYB N

2) PPB are programmed individually 3) DYB are volatile bits

but erased as a group

Every main flash array sector has a non-volatile (PPB) and a volatile (DYB) protection bit associated with it. When either bit is 0, the

sector is protected from program and erase operations.

The PPB bits are protected from program and erase when the PPB Lock bit is 0. There are two methods for managing the state of

the PPB Lock bit, Persistent Protection and Password Protection.

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.

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. This method requires use of a password to control PPB protection.

The selection of the PPB Lock bit management method is made by programming OTP bits in the ASP Register so as to permanently

select the method used.

Document Number: 001-98283 Rev. *I

Page 59 of 144

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