at52bc1661a ATMEL Corporation, at52bc1661a Datasheet - Page 6

• Manufacturer Part Number: at52bc1661a
• Description: 16-mbit Flash + 8-mbit Psram Stack Memory
• Manufacturer: ATMEL Corporation

ERASURE: Before a word can be reprogrammed, it must be erased. The erased state of
memory bits is a logical “1”. The entire device can be erased by using the Chip Erase com-
mand or individual sectors can be erased by using the Sector Erase command.
CHIP ERASE: The entire device can be erased at one time by using the six-byte chip erase
software code. After the chip erase has been initiated, the device will internally time the erase
operation so that no external clocks are required. The maximum time to erase the chip is t
.
EC
If the sector lockdown has been enabled, the chip erase will not erase the data in the sector
that has been locked out; it will erase only the unprotected sectors. After the chip erase, the
device will return to the read or standby mode.
SECTOR ERASE: As an alternative to a full chip erase, the device is organized into 39 sec-
tors (SA0 - SA38) that can be individually erased. The Sector Erase command is a six-bus
cycle operation. The sector address is latched on the falling WE edge of the sixth cycle while
the 30H data input command is latched on the rising edge of WE. The sector erase starts after
the rising edge of WE of the sixth cycle. The erase operation is internally controlled; it will
automatically time to completion. The maximum time to erase a sector is t
. When the sec-
SEC
tor programming lockdown feature is not enabled, the sector will erase (from the same Sector
Erase command). An attempt to erase a sector that has been protected will result in the oper-
ation terminating immediately.
WORD PROGRAMMING: Once a memory block is erased, it is programmed (to a logical “0”)
on a word-by-word basis. Programming is accomplished via the internal device command reg-
ister and is a four-bus cycle operation. The device will automatically generate the required
internal program pulses.
Any commands written to the chip during the embedded programming cycle will be ignored. If
a hardware reset happens during programming, the data at the location being programmed
will be corrupted. Please note that a data “0” cannot be programmed back to a “1”; only erase
operations can convert “0”s to “1”s. Programming is completed after the specified t
cycle
BP
time. The Data Polling feature or the Toggle Bit feature may be used to indicate the end of a
program cycle. If the erase/program status bit is a “1”, the device was not able to verify that the
erase or program operation was performed successfully.
VPP PIN: The circuitry of the device is designed so that it cannot be programmed or erased if
the V
voltage is less that 0.4V. When V
is at 0.9V or above, normal program and erase
PP
PP
operations can be performed. The VPP pin cannot be left floating.
PROGRAM/ERASE STATUS: The device provides several bits to determine the status of a
program or erase operation: I/O2, I/O3, I/O5, I/O6 and I/O7. The “Status Bit Table” on page 12
and the following four sections describe the function of these bits. To provide greater flexibility
for system designers, the Flash contains a programmable configuration register. The configu-
ration register allows the user to specify the status bit operation. The configuration register can
be set to one of two different values, “00” or “01”. If the configuration register is set to “00”, the
part will automatically return to the read mode after a successful program or erase operation. If
the configuration register is set to a “01”, a Product ID Exit command must be given after a
successful program or erase operation before the part will return to the read mode. It is impor-
tant to note that whether the configuration register is set to a “00” or to a “01”, any
unsuccessful program or erase operation requires using the Product ID Exit command to
return the device to read mode. The default value (after power-up) for the configuration regis-
ter is “00”. Using the four-bus cycle Set Configuration Register command as shown in the
“Command Definition in Hex” table on page 13, the value of the configuration register can be
changed. Voltages applied to the RESET pin will not alter the value of the configuration regis-
ter. The value of the configuration register will affect the operation of the I/O7 status bit as
described below.
AT52BC1661A(T) [Preliminary]
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3455A–STKD–11/04