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White Electronic Designs Corporation (602) 437-1520 www.whiteedc.com
White Electronic Designs
W78M64V-XSBX
July 2006
Rev. 4
White Electronic Designs Corp. reserves the right to change products or specications without notice.
TEMPORARY SECTOR UNPROTECT
This feature allows temporary unprotection of previously
protected sectors to change data in-system. The Sector
Unprotect mode is activated by setting the RESET# pin to
VID. During this mode, formerly protected sectors can be
programmed or erased by selecting the sector addresses.
Once VID is removed from the RESET# pin, all the previously
protected sectors are protected again. Figure 3 shows the
algorithm, and Figure 24 shows the timing diagrams, for
this feature. While PPB lock is set, the device cannot enter
the Temporary Sector Unprotection Mode.
SecSi sector is divided into 64 factory-lockable words that
can be programmed and locked by the user. The SecSi
sector is located at addresses 000000h-00007Fh in both
Persistent Protection mode and Password Protection mode.
It uses indicator bits (DQ6, DQ7) to indicate the factory-
locked and user-locked status of the part.
The system accesses the SecSi Sector through a command
sequence (see “Enter SecSi Sector/Exit SecSi Sector
Command Sequence”). After the sysem has written the
Enter SecSi Sector command sequence, it may read the
SecSi Sector by using the addresses normally occupied by
the boot sectors. This mode of operation continues until the
system issues the Exit SecSi Sector command sequence,
or until power is removed from the device. On power-up, or
following a hardware reset, the device reverts to sending
commands to the normal address space. Note that the ACC
function and unlock bypass modes are not available when
the SecSi Sector is enabled.
Factory-Locked Area (64 words)
The factory-locked area of the SecSi Sector (000000h-
00003Fh) is locked when the part is shipped, whether or
not the area was programmed at the factory. The SecSi
Sector Factory-locked Indicator Bit (DQ7) is permanently
set to a “1”.
User-Lockable Area (64 words)
The user-lockable area of the SecSi Sector (000040h-
00007Eh) is shipped unprotected, which allows the user
to program and optionally lock the area as appropriate for
the application. The SecSi Sector User-locked Indicator Bit
(DQ6) is shipped as “0” and can be permanently locked to
“1” by issuing the SecSi Protection Bit Program Command.
The SecSi Sector can be read any number of times, but
can be programmed and locked only once. Note that
the accelerated programming (ACC) and unlock bypass
functions are not available when programming the SecSi
Sector.
The User-lockable SecSi Sector area can be protected using
one of the following procedures:
Follow the SecSi Sector protection Agorithm as
shown in Figure 4. This allows in-system protection
of the SecSi Sector without raising any device pin
to a high voltage. Note that this method is only
appliacable to the SecSi Sector.
To verify the protect/unprotect status of the SecSi
Sector, follow the algorithm shown in Figure 5.
SecSi (SECURED SILICON) SECTOR
FLASH MEMORY REGION
The SecSi (Secured Silicon) Sector feature provides a Flash
memory region that enables permanent part identication
through an Electronic Serial Number (ESN) The 128-word
START
Perform Erase or
Program Operations
RESET# = V
IH
Temporary Sector
Unprotect Completed
(Note 2)
RESET# = V
ID
(Note 1)
FIGURE 3. TEMPORARY SECTOR UNPROTECT
OPERATION
Notes:
1.
All protected sectors unprotected (If WP#/ACC = VIL, sectors 0, 1, 268, 269 will
remain protected).
2.
All previously protected sectors are protected once again