S29PL-N_07 SPANSION [SPANSION], S29PL-N_07 Datasheet - Page 46

• Manufacturer Part Number: S29PL-N_07
• Description: 256/128/128 Mb (16/8/8 M x 16-Bit) CMOS, 3.0 Volt-only Simultaneous Read/Write, Page-Mode Flash Memory
• Manufacturer: SPANSION [SPANSION]

8.2
8.3
46
Persistent Protection Bits
Dynamic Protection Bits
The Persistent Protection Bits are unique and nonvolatile for each sector and have the same endurances as
the Flash memory. Preprogramming and verification prior to erasure are handled by the device, and therefore
do not require system monitoring.
Notes
Dynamic Protection Bits are volatile and unique for each sector and can be individually modified. DYBs only
control the protection scheme for unprotected sectors that have their PPBs cleared (erased to 1). By issuing
the DYB Set or Clear command sequences, the DYBs are set (programmed to 0) or cleared (erased 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.
Notes
1. Each PPB is individually programmed and all are erased in parallel.
2. Entry command disables reads and writes for the bank selected.
3. Reads within that bank return the PPB status for that sector.
4. Reads from other banks are allowed while writes are not allowed.
5. All Reads must be performed using the Asynchronous mode.
6. The specific sector addresses (A23 – A14 PL256N and A22 – A14 PL127N/PL129N) are written at
7. If the PPB Lock Bit is set, the PPB Program or erase command does not execute and times-out
8. There are no means for individually erasing a specific PPB and no specific sector address is
9. Exit command must be issued after the execution which resets the device to read mode and re-
10. The programming state of the PPB for a given sector can be verified by writing a PPB Status Read
1. The DYBs can be set (programmed to 0) or cleared (erased to 1) as often as needed. When the
2. If the option to clear the DYBs after power up is chosen, (erased to 1), then the sectors may be
3. The sectors would be in the protected state If the option to set the DYBs after power up is chosen
4. It is possible to have sectors that are persistently locked with sectors that are left in the dynamic
5. The DYB Set or Clear commands for the dynamic sectors signify protected or unprotected state of
6. To achieve the best protection, it is recommended to execute the PPB Lock Bit Set command early
the same time as the program command.
without programming or erasing the PPB.
required for this operation.
enables reads and writes for Bank A.
Command to the device as described by the flow chart below.
parts are first shipped, the PPBs are cleared (erased to 1) and upon power up or reset, the DYBs
can be set or cleared depending upon the ordering option chosen.
modified depending upon the PPB state of that sector.
(programmed to 0).
state.
the sectors respectively. However, if there is a need to change the status of the persistently locked
sectors, 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.
in the boot code and protect the boot code by holding WP# = V
have the same function when WP#/ACC = V
S29PL-N MirrorBit
D a t a
S h e e t
™
Flash Family
HH
( P r e l i m i n a r y )
as they do when WP#/ACC = V
IL
. Note that the PPB and DYB bits
S29PL-N_00_A5 June 6, 2007
IH
.