s71ws512ne0bfwzz Meet Spansion Inc., s71ws512ne0bfwzz Datasheet - Page 32

• Manufacturer Part Number: s71ws512ne0bfwzz
• Description: Stacked Multi-chip Product Mcp Flash Memoy And Psram Cmos 1.8 Volt, Simultaneous Operation, Burst Mode Flash Memory And Pseudo-static Ram
• Manufacturer: Meet Spansion Inc.

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When the parts are first shipped, the PPBs are cleared (erased to “1”) and upon
power up or reset, the DYBs are set or cleared depending upon the ordering op-
tion chosen. If the option to clear the DYBs after power up is chosen, (erased to
“1”), then the sectors may be modified depending upon the PPB state of that sec-
tor. (See
(programmed to “0”), then the sectors would be in the protected state. The PPB
Lock Bit defaults to the cleared state (erased to “1”) after power up and the PPBs
retain their previous state as they are non-volatile. The default DYB state is
cleared (erased to “1”) with the sectors in the unprotected state.
It is possible to have sectors that have been persistently locked, and sectors that
are left in the dynamic state. The sectors in the dynamic state are all unprotected.
If there is a need to protect some of them, a simple DYB Set command sequence
is all that is necessary. The DYB Set or Clear command for the dynamic sectors
signify protected or unprotected state of 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 will lock the
PPBs, and the device operates normally again.
Note: to achieve the best protection, it’s recommended to execute the PPB Lock
Bit Set command early in the boot code, and protect the boot code by holding
WP# = V
VHH as they do when ACC = V
Table 5
to the status of the sector.
In summary, if the PPB is set (programmed to “0”), and the PPB Lock is set (pro-
grammed to “0”), the sector is protected and the protection can not be removed
until the next power cycle clears (erase to “1”) the PPB Lock Bit. Once the PPB
Lock Bit is cleared (erased to “1”), the sector can be persistently locked or un-
locked. Likewise, if both PPB Lock Bit or PPB is cleared (erased to “1”) the sector
can then be dynamically locked or unlocked. The DYB 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 or erase command to a pro-
DYB
1
0
1
0
1
0
1
0
contains all possible combinations of the DYB, PPB, and PPB Lock relating
IL
Table
. Note that the PPB and DYB bits have the same function when ACC =
S29WSxxxN MirrorBit™ Flash Family For Multi-chip Products (MCP) S71WS512NE0BFWZZ_00_ A1 June 28, 2004
5) If the option to set the DYBs after power up is chosen
Table 5. Sector Protection Schemes
PPB
1
1
0
0
1
1
0
0
A d v a n c e
IH
.
PPB Lock
1
1
1
1
0
0
0
0
I n f o r m a t i o n
Sector Protected through DYB
Sector Protected through DYB
Sector Protected through PPB
Sector Protected through PPB
Sector Protected through PPB
Sector Protected through PPB
Sector Unprotected
Sector Unprotected
Sector State
and DYB
and DYB