S29CD032J datasheet(48/81 Pages) SPANSION

48 / 81 page

S29CD-J and S29CL-J Flash Family

S29CD-J_CL-J_00_B7 October 11, 2012

Da ta

Sh e e t

4. The DYB Set or Clear commands for the dynamic sector groups signify the protected or

unprotected state of the sector groups respectively. However, if there is a need to change the

status of the persistently locked sector groups, a few more steps are required. First, the PPB Lock

Bit must be cleared by either putting the device through a power-cycle, or hardware reset. The

PPBs can then be changed to reflect the desired settings. Setting the PPB Lock Bit once again

locks the PPBs, and the device operates normally again.

9.5

Password Protection Method

The Password Protection Method allows an even higher level of security than the Persistent Sector Protection

Mode by requiring a 64-bit password for unlocking the device PPB Lock Bit. In addition to this password

requirement, after power-up and reset, the PPB Lock Bit is set “1” in order to maintain the password mode of

operation. Successful execution of the Password Unlock command by entering the entire password clears the

PPB Lock Bit, allowing for sector PPBs modifications.

Notes

1. There is no special addressing order required for programming the password. Once the password

is written and verified, the Password Mode Locking Bit must be set in order to prevent access.

2. The Password Program Command is only capable of programming “0”s. Programming a “1” after a

cell is programmed as a “0” results in a time-out with the cell as a “0”. (This is an OTP area).

3. The password is all “1”s when shipped from the factory.

4. When the password is undergoing programming, Simultaneous Read/Write operation is disabled.

Read operations to any memory location returns the programming status. Once programming is

complete, the user must issue a Read/Reset command to return the device to normal operation.

5. All 64-bit password combinations are valid as a password.

6. There is no means to read, program or erase the password is after it is set.

7. The Password Mode Lock Bit, once set, prevents reading the 64-bit password on the data bus and

further password programming.

8. The Password Mode Lock Bit is not erasable.

9. The exact password must be entered in order for the unlocking function to occur.

10. There is a built-in 2-µs delay for each password check. This delay is intended to stop any efforts to

run a program that tries all possible combinations in order to crack the password.

Table 9.1 Sector Protection Schemes

DYB

PPB

PPB Lock

Sector State

Unprotected—PPB and DYB are changeable

Unprotected—PPB not changeable, DYB is changeable

Protected—PPB and DYB are changeable

Protected—PPB not changeable, DYB is changeable

S29CD032J Datasheet(PDF) 48 Page - SPANSION

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