9
AT52BR3224A(T)/3228A(T)
3338A–STKD–1/03
SECTOR LOCKDOWN OVERRIDE: The only way to unlock a sector that is locked down is
through reset or power-u p cycles. After power-up or rese t, the content of a sector that is
locked down can be erased and reprogrammed.
ERASE SUSPEND/ERASE RESUME: The Eras e Suspend comman d allows the syste m to
interrupt a sector or chip erase operation and then program or read data from a different sector
within the memory. After the Erase Suspend command is given, the devic e requires a maxi-
mum time of 15 µs to suspend the erase operation. After the erase operation has been
suspended, the system can then read data or program data to any other sector within the
device. An address is not required during the Erase Suspend command. During a sector erase
suspend , anot her sector cannot be er ased. To resume the se cto r eras e ope ration, the syste m
must write the Erase Resume command. The Erase Resume command is a one-bus cycle
command. The device also supports an erase suspend during a complete chip erase. While
the chip era se is su sp end ed, the use r can re ad fr om any se cto r wi thin the mem or y that is pro-
tected. The command sequence for a chip erase suspend and a sector erase suspend are the
same.
PROGRAM SUSPEND/PROGRAM RESUME: The P rogram Suspend command al lows the
system to interrupt a programming operation and then read data from a different word within
the memo ry. After the Program Suspend command is given, the device requires a maximum
of 20 µs to suspend the programming operation. After the programming operation has been
suspended, the system can then read data from any other word within the device that is not
contained in the sector in which the programming operation was suspended. An address is not
required during the program suspend operation. To resume the programming operation, the
system mus t write the Progra m Resume comman d. The program suspe nd and resume ar e
one-bus cycle commands. The command sequence for the erase su spend and program sus-
pend are the same, and the command sequence for the erase resume and program resume
are the same.
PRODUCT IDENTIFICATION: The pr odu ct identific atio n mo de i dent ifi es t he de vi ce and m an-
ufacturer as Atmel. It may be accessed by hardware or software operation. The hardwar e
operation mode can be used by an external programmer to identify the correct programming
algorithm for the Atmel product.
For detail s, see “O perating M odes” on page 20 (for hardwa re oper ation ) or “Softwar e Produc t
Identification Entry/Exit” sections on page 27. The manufacturer and device codes are the
same for both modes.
128-BIT PROTECTION REGISTER: The device contains a 128-bit register that can be used
for security purposes in system design. The protection register is divided into two 64-bit
blocks. The two blocks are designated as block A and block B. The data in block A is
non-cha ngeable a nd is p rogram med at th e facto ry with a unique num ber. Th e data i n bloc k B
is programmed by the user and can be locked out such that data in the block cannot be repro-
grammed. To program block B in the protection register, the four-bus cycle Program
Protection Register command must be used as shown in the “Command Definition in Hex”
table on page 14. To lock out block B, the four-bus cycle Lock Protection Register command
must be used as shown in the “Command Definition in Hex” table. Data bit D1 must be zero
duri ng the f ourth bu s cycl e. All ot her data bits d uring t he four th bus cycle ar e don’t cares. To
determine whether block B is locked out, the Product ID Entry command is given followed by a
read operation from address 80H. If data bit D1 is zero, block B is locked. If data bit D1 is one,
block B can be reprogrammed. Please see the “Protection Register Addressing Table” on
page 15 for the address locations in the protection register. To read the protection register, the
Product ID Entry command is given followed by a normal read operation from an address
within the protection register. After determining whether block B is protected or not, or reading
the protec tion register , the Product ID Exit co mmand must be given p rior to perform ing any
other operation.