at52bc3221a ATMEL Corporation, at52bc3221a Datasheet - Page 7

• Manufacturer Part Number: at52bc3221a
• Description: 32-mbit Flash 8-mbit Psram Stack Memory
• Manufacturer: ATMEL Corporation

AT52BC3221A(T)
erase/program status bit is a “0” while the erase or program operation is still in progress.
Please see “Status Bit Table” on page 11 for more details.
V
STATUS BIT: The device provides a status bit on I/O3, which provides information
PP
regarding the voltage level of the VPP pin. During a program or erase operation, if the voltage
on the VPP pin is not high enough to perform the desired operation successfully, the I/O3 sta-
tus bit will be a “1”. Once the V
status bit has been set to a “1”, the system must write the
PP
Product ID Exit command to return to the read mode. On the other hand, if the voltage level is
high enough to perform a program or erase operation successfully, the V
status bit will out-
PP
put a “0”. Please see “Status Bit Table” on page 11 for more details.
SECTOR LOCKDOWN: Each sector has a programming lockdown feature. This feature pre-
vents programming of data in the designated sectors once the feature has been enabled.
These sectors can contain secure code that is used to bring up the system. Enabling the lock-
down feature will allow the boot code to stay in the device while data in the rest of the device is
updated. This feature does not have to be activated; any sector’s usage as a write-protected
region is optional to the user.
At power-up or reset, all sectors are unlocked. To activate the lockdown for a specific sector,
the six-bus cycle Sector Lockdown command must be issued. Once a sector has been locked
down, the contents of the sector is read-only and cannot be erased or programmed.
SECTOR LOCKDOWN DETECTION: A software method is available to determine if program-
ming of a sector is locked down. When the device is in the software product identification
mode (see “Software Product Identification Entry/Exit” sections on page 24), a read from
address location 00002H within a sector will show if programming the sector is locked down. If
the data on I/O0 is low, the sector can be programmed; if the data on I/O0 is high, the program
lockdown feature has been enabled and the sector cannot be programmed. The software
product identification exit code should be used to return to standard operation.
SECTOR LOCKDOWN OVERRIDE: The only way to unlock a sector that is locked down is
through reset or power-up cycles. After power-up or reset, the content of a sector that is
locked down can be erased and reprogrammed.
ERASE SUSPEND/ERASE RESUME: The Erase Suspend command allows the system 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 device 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, another sector cannot be erased. To resume the sector erase operation, the system
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 erase is suspended, the user can read from any sector within the memory 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 Program Suspend command allows the
system to interrupt a programming operation and then read data from a different word within
the memory. 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 must write the Program Resume command. The program suspend and resume are
one-bus cycle commands. The command sequence for the erase suspend and program sus-
pend are the same, and the command sequence for the erase resume and program resume
are the same.
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