A d v a n c e I n f o r m a t i o n
The SecSi Sector Entry command is allowed when the device is in either program
or erase suspend modes. If the SecSi sector is enabled, the program or erase sus-
pend command is ignored. This prevents resuming either programming or
erasure on the SecSi sector if the overlayed sector was undergoing programming
or erasure. The host system must ensure that the device resume any sus-
pended program or erase operation after exiting the SecSi sector.
Executing any of the PPB program/erase commands, or Password Unlock com-
mand results in the small bank (25% bank) returning the status of these
operations while they are in progress, thus making the SecSi sector unavailable
for reading. If the SecSi sector is enabled while the DYB command is issued, the
DYB for the overlayed sector is NOT updated. Reading the DYB status using the
PPB Lock Bit/DYBDYB verify command when the SecSi sector is enabled returns
invalid data.
Password Program Command
The Password Program Command permits programming the password that is
used as part of the hardware protection scheme. The actual password is 64-bits
long. Depending upon the state of the WORD# pin, multiple Password Program
Commands are required. For a x32 bit data bus, 2 Password Program commands
are required. The user must enter the unlock cycle, password program command
(38h) and the program address/data for each portion of the password when pro-
gramming. There are no provisions for entering the 2-cycle unlock cycle, the
password program command, and all the password data. There is no special ad-
dressing order required for programming the password. Also, when the password
is undergoing programming, Simultaneous Read/Write operation is disabled.
Read operations to any memory location will return the programming status.
Once programming is complete, the user must issue a Read/Reset command to
return the device to normal operation. Once the Password is written and verified,
the Password Mode Locking Bit must be set in order to prevent verification. 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 by the Embedded
Program Algorithm™ with the cell remaining as a “0”. The password is all F’s when
shipped from the factory. All 64-bit password combinations are valid as a
password.
Password Programming is permitted if the SecSi sector is enabled.
Password Verify Command
The Password Verify Command is used to verify the Password. The Password is
verifiable only when the Password Mode Locking Bit is not programmed. If the
Password Mode Locking Bit is programmed and the user attempts to verify the
Password, the device will always drive all F’s onto the DQ data bus.
The Password Verify command is permitted if the SecSi sector is enabled. Also,
Simultaneous Read/Write operation is disabled when the Password Verify com-
mand is executed. Only the password is returned regardless of the bank address.
The lower two address bits (A0:A-1) are valid during the Password Verify. Writing
the Read/Reset command returns the device back to normal operation.
Password Protection Mode Locking Bit Program Command
The Password Protection Mode Locking Bit Program Command programs the
Password Protection Mode Locking Bit, which prevents further verifies or updates
to the Password. Once programmed, the Password Protection Mode Locking Bit
56
S29CD032G
30606B0 March 22, 2004
SPANSION [ SPANSION ]
