at49bv163d ATMEL Corporation, at49bv163d Datasheet - Page 5

• Manufacturer Part Number: at49bv163d
• Description: 16-megabit 1m X 16/2m X 8 3-volt Only Flash Memory
• Manufacturer: ATMEL Corporation

4.6.1
4.6.2
4.6.3
4.7
3590A–FLASH–12/05
Sector Lockdown
DATA Polling
Toggle Bit
Erase/Program Status Bit
of the configuration register can be changed. Voltages applied to the RESET pin will not alter the
value of the configuration register. The value of the configuration register will affect the operation
of the I/O7 status bit as described below.
The AT49BV163D(T) features Data Polling to indicate the end of a program cycle. If the status
configuration register is set to a “00”, during a program cycle an attempted read of the last
byte/word loaded will result in the complement of the loaded data on I/O7. Once the program
cycle has been completed, true data is valid on all outputs and the next cycle may begin. During
a chip or sector erase operation, an attempt to read the device will give a “0” on I/O7. Once the
program or erase cycle has completed, true data will be read from the device. Data Polling may
begin at any time during the program cycle. Please see
details.
If the status bit configuration register is set to a “01”, the I/O7 status bit will be low while the
device is actively programming or erasing data. I/O7 will go high when the device has completed
a program or erase operation. Once I/O7 has gone high, status information on the other pins can
be checked.
The Data Polling status bit must be used in conjunction with the erase/program status bit as
shown in the algorithm in
In addition to Data Polling the AT49BV163D(T) provides another method for determining the end
of a program or erase cycle. During a program or erase operation, successive attempts to read
data from the memory will result in I/O6 toggling between one and zero. Once the program cycle
has completed, I/O6 will stop toggling and valid data will be read. Examining the toggle bit may
begin at any time during a program cycle. Please see
details.
The toggle bit status bit should be used in conjunction with the erase/program status bit as
shown in the algorithm in
The device offers a status bit on I/O5, which indicates whether the program or erase operation
has exceeded a specified internal pulse count limit. If the status bit is a “1”, the device is unable
to verify that an erase or a byte/word program operation has been successfully performed. If a
program (Sector Erase) command is issued to a protected sector, the protected sector will not
be programmed (erased). The device will go to a status read mode and the I/O5 status bit will be
set high, indicating the program (erase) operation did not complete as requested. Once the
erase/program status bit has been set to a “1”, the system must write the Product ID Exit com-
mand to return to the read mode. The erase/program status bit is a “0” while the erase or
program operation is still in progress. Please see
Each sector has a programming lockdown feature. This feature prevents 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 lockdown 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.
Figures 4-1 and
Figures 4-3 and
and
and
4-2
4-4
“Status Bit Table” on page 10
on
on
page
page
“Status Bit Table” on page 10
“Status Bit Table” on page 10
8.
9.
AT49BV163D(T)
for more details.
for more
for more
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