AM29PDL640AGA85NS SPANSION [SPANSION], AM29PDL640AGA85NS Datasheet - Page 33

• Manufacturer Part Number: AM29PDL640AGA85NS
• Description: 64 Megabit (4 M x 16-Bit) CMOS 3.0 Volt-only, Simultaneous Operation Flash Memory and 16 Mbit (1 M x 16-Bit) Pseudo Static RAM
• Manufacturer: SPANSION [SPANSION]

of the password when programming. There are no pro-
visions for entering the 2-cycle unlock cycle, the pass-
word program command, and all the password data.
There is no special addressing order required for pro-
gramming the password. Also, when the password is
undergoing programming, Simultaneous 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 com-
mand 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 verifi-
cation. The Password Program Command is only ca-
pable 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 remain-
ing as a “0”. The password is all ones when shipped
from the factory. All 64-bit password combinations are
valid as a password.
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 al-
ways drive all F’s onto the DQ data bus.
The Password Verify command is permitted if the
SecSi sector is enabled. Also, the device will not oper-
ate in Simultaneous Operation when the Password
Verify command is executed. Only the password is re-
turned regardless of the bank address. The lower two
address bits (A1-A0) 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 cannot be erased! If the
Password Protection Mode Locking Bit is verified as
program without margin, the Password Protection
Mode Locking Bit Program command can be executed
to improve the program margin. Once the Password
Protection Mode Locking Bit is programmed, the Per-
sistent Sector Protection Locking Bit program circuitry
is disabled, thereby forcing the device to remain in the
Password Protection mode. Exiting the Mode Locking
Bit Program command is accomplished by writing the
Read/Reset command.
November 20, 2003
P R E L I M I N A R Y
Am49PDL640AG
Persistent Sector Protection Mode
Locking Bit Program Command
The Persistent Sector Protection Mode Locking Bit
Program Command programs the Persistent Sector
Protection Mode Locking Bit, which prevents the Pass-
word Mode Locking Bit from ever being programmed.
If the Persistent Sector Protection Mode Locking Bit is
verified as programmed without margin, the Persistent
Sector Protection Mode Locking Bit Program Com-
mand should be reissued to improve program margin.
By disabling the program circuitry of the Password
Mode Locking Bit, the device is forced to remain in the
Persistent Sector Protection mode of operation, once
this bit is set. Exiting the Persistent Protection Mode
Locking Bit Program command is accomplished by
writing the Read/Reset command.
SecSi Sector Protection Bit Program
Command
The SecSi Sector Protection Bit Program Command
programs the SecSi Sector Protection Bit, which pre-
vents the SecSi sector memory from being cleared. If
the SecSi Sector Protection Bit is verified as pro-
grammed without margin, the SecSi Sector Protection
Bit Program Command should be reissued to improve
program margin. Exiting the V
Protection Bit Program Command is accomplished by
writing the Read/Reset command.
PPB Lock Bit Set Command
The PPB Lock Bit Set command is used to set the
PPB Lock bit if it is cleared either at reset or if the
Password Unlock command was successfully exe-
cuted. There is no PPB Lock Bit Clear command.
Once the PPB Lock Bit is set, it cannot be cleared un-
less the device is taken through a power-on clear or
the Password Unlock command is executed. Upon set-
ting the PPB Lock Bit, the PPBs are latched into the
DYBs. If the Password Mode Locking Bit is set, the
PPB Lock Bit status is reflected as set, even after a
power-on reset cycle. Exiting the PPB Lock Bit Set
command is accomplished by writing the Read/Reset
command (only in the Persistent Protection Mode).
DYB Write Command
The DYB Write command is used to set or clear a DYB
for a given sector. The high order address bits
(A21–A12) are issued at the same time as the code
01h or 00h on DQ7-DQ0. All other DQ data bus pins
are ignored during the data write cycle. The DYBs are
modifiable at any time, regardless of the state of the
PPB or PPB Lock Bit. The DYBs are cleared at
power-up or hardware reset.Exiting the DYB Write
command is accomplished by writing the Read/Reset
command.
CC
-level SecSi Sector
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