lected (WORD# = 0). Writing the Password Unlock
command is address order specific. In other words, for
the x32 data bus configuration, the lower 32 bits of the
password are written first and then the upper 32 bits of
the password are written. For the x16 data bus config-
uration, the lower address A0:A-1= 00, the next Pass-
word Unlock command is to A0:A-1= 01, then to
A0:A-1= 10, and finally to A0:A-1= 11. Writing out of se-
quence results in the Password Unlock not returning a
match with the password and the PPB Lock Bit re-
mains set.
All PPB Erase Command
The All PPB Erase command is used to erase all
PPBs in bulk. There is no means for individually eras-
ing a specific PPB. Unlike the PPB program, no spe-
cific sector address is required. However, when the
PPB erase command is written (60h) and A6 = 1, all
Sector PPBs are erased in parallel. If the PPB Lock Bit
is set the ALL PPB Erase command will not execute
and the command will time-out without erasing the
PPBs. The host system must determine whether all
PPB has been fully erased by noting the status of DQ0
in the sixth cycle of the All PPB Erase command. If
DQ0 = 1, the entire six-cycle All PPB Erase command
sequence must be reissued until DQ0 = 1.
Once the Password Unlock command is entered, the
RDY/BSY# pin goes LOW indicating that the device is
busy. Also, reading the small bank (25% bank) results
in the DQ6 pin toggling, indicating that the Password
Unlock function is in progress. Reading the large bank
(75% bank) returns actual array data. Approximately
1uSec is required for each portion of the unlock. Once
the first portion of the password unlock completes
(RDY/BSY# is not driven and DQ6 does not toggle
when read), the Password Unlock command is issued
again, only this time with the next part of the pass-
word. If WORD# = 1, the second Password Unlock
command is the final command before the PPB Lock
Bit is cleared (assuming a valid password). If WORD#
= 0, this is the fourth Password Unlock command. In
x16 mode, four Password Unlock commands are re-
quired to successfully clear the PPB Lock Bit. As with
the first Password Unlock command, the RY/BY# sig-
nal goes LOW and reading the device results in the
DQ6 pin toggling on successive read operations until
complete. It is the responsibility of the microprocessor
to keep track of the number of Password Unlock com-
mands (2 for x32 bus and 4 for x16 bus), the order,
and when to read the PPB Lock bit to confirm suc-
cessful password unlock
It is the responsibility of the user to preprogram all
PPBs prior to issuing the All PPB Erase command. If
the user attempts to erase a cleared PPB, over-era-
sure may occur making it difficult to program the PPB
at a later time. Also note that the total number of PPB
program/erase cycles is limited to 100 cycles. Cycling
the PPBs beyond 100 cycles is not guaranteed.
The All PPB Erase command is permitted if the SecSi
sector is enabled.
DYB Write
The DYB Write command is used for setting the DYB,
which is a volatile bit that is cleared at reset. There is
one DYB per sector. If the PPB is set, the sector is
protected regardless of the value of the DYB. If the
PPB is cleared, setting the DYB to a 1 protects the
sector from programs or erases. Since this is a volatile
bit, removing power or resetting the device will clear
the DYBs. The bank address is latched when the com-
mand is written.
The DYB Write command is permitted if the SecSi
sector is enabled.
The Password Unlock command is permitted if the
SecSi sector is enabled.
PPB Lock Bit Set
PPB Program Command
The PPB Lock Bit set command is used for setting the
DYB, which is a volatile bit that is cleared at reset.
There is one DYB per sector. If the PPB is set, the
sector is protected regardless of the value of the DYB.
If the PPB is cleared, setting the DYB to a 1 protects
the sector from programs or erases. Since this is a vol-
atile bit, removing power or resetting the device will
clear the DYBs. The bank address is latched when the
command is written.
The PPB Program command is used to program, or
set, a given PPB. Each PPB is individually pro-
grammed (but is bulk erased with the other PPBs).
The specific sector address (A18–A11) are written at
the same time as the program command 60h with A6
= 0. If the PPB Lock Bit is set and the corresponding
PPB is set for the sector, the PPB Program command
will not execute and the command will time-out without
programming the PPB.
The PPB Lock command is permitted if the SecSi sec-
tor is enabled.
The host system must determine whether a PPB has
been fully programmed by noting the status of DQ0 in
the sixth cycle of the PPB Program command. If DQ0
= 0, the entire six-cycle PPB Program command se-
quence must be reissued until DQ0 = 1.
DYB Status
The programming of the DYB for a given sector can be
verified by writing a DYB status verify command to the
device.
June 7, 2006
Am29BDD160G
43
SPANSION [ SPANSION ]
