AM29F100T-90SC AMD (ADVANCED MICRO DEVICES), AM29F100T-90SC Datasheet - Page 13

• Manufacturer Part Number: AM29F100T-90SC
• Manufacturer: AMD (ADVANCED MICRO DEVICES)

Specifications of AM29F100T-90SC

• Lead Free Status / Rohs Status: Not Compliant

Chip Erase Command Sequence
Chip erase is a six-bus-cycle operation. The chip erase
command sequence is initiated by writing two unlock
cycles, followed by a set-up command. Two additional
unlock write cycles are then followed by the chip erase
command, which in turn invokes the Embedded Erase
algorithm. The device does not require the system to
preprogram prior to erase. The Embedded Erase algo-
rithm automatically preprograms and verifies the entire
memory for an all zero data pattern prior to electrical
erase. The system is not required to provide any con-
trols or timings during these operations. The Command
Definitions table shows the address and data require-
ments for the chip erase command sequence.
Any commands written to the chip during the Embed-
ded Erase algorithm are ignored. Note that a hardware
reset during the chip erase operation immediately ter-
minates the operation. The Chip Erase command
sequence should be reinitiated once the device has re-
turned to reading array data, to ensure data integrity.
The system can determine the status of the erase op-
eration by using DQ7, DQ6, or RY/BY#. See “Write
Operation Status” for information on these status bits.
When the Embedded Erase algorithm is complete, the
device returns to reading array data and addresses are
no longer latched.
Figure 3 illustrates the algorithm for the erase opera-
tion. See the Erase/Program Operations tables in “AC
Characteristics” for parameters, and to the Chip/Sector
Erase Operation Timings for timing waveforms.
Sector Erase Command Sequence
Sector erase is a six bus cycle operation. The sector
erase command sequence is initiated by writing two
unlock cycles, followed by a set-up command. Two ad-
ditional unlock write cycles are then followed by the
address of the sector to be erased, and the sector
erase command. The Command Definitions table
shows the address and data requirements for the sec-
tor erase command sequence.
The device does not require the system to preprogram
the memory prior to erase. The Embedded Erase algo-
rithm automatically programs and verifies the sector for
an all zero data pattern prior to electrical erase. The
system is not required to provide any controls or tim-
ings during these operations.
After the command sequence is written, a sector erase
time-out of 50 µs begins. During the time-out period,
additional sector addresses and sector erase com-
mands may be written. Loading the sector erase buffer
may be done in any sequence, and the number of sec-
tors may be from one sector to all sectors. The time
between these additional cycles must be less than 50
be accepted, and erasure may begin. It is recom-
s, otherwise the last address and command might not
Am29F100
mended that processor interrupts be disabled during
this time to ensure all commands are accepted. The in-
terrupts can be re-enabled after the last Sector Erase
command is written. If the time between additional sec-
tor erase commands can be assumed to be less than
50 µs, the system need not monitor DQ3. Any com-
mand other than Sector Erase or Erase Suspend
during the time-out period resets the device to
reading array data. The system must rewrite the com-
mand sequence and any additional sector addresses
and commands.
The system can monitor DQ3 to determine if the sector
erase timer has timed out. (See the “DQ3: Sector
Erase Timer” section.) The time-out begins from the ris-
ing edge of the final WE# pulse in the command
sequence.
Once the sector erase operation has begun, only the
Erase Suspend command is valid. All other commands
are ignored. Note that a hardware reset during the
sector erase operation immediately terminates the op-
eration. The Sector Erase command sequence should
be reinitiated once the device has returned to reading
array data, to ensure data integrity.
When the Embedded Erase algorithm is complete, the
device returns to reading array data and addresses are
no longer latched. The system can determine the sta-
tus of the erase operation by using DQ7, DQ6, or RY/
BY#. Refer to “Write Operation Status” for information
on these status bits.
Figure 3 illustrates the algorithm for the erase opera-
tion. Refer to the Erase/Program Operations tables in
the “AC Characteristics” section for parameters, and to
the Sector Erase Operations Timing diagram for timing
waveforms.
Erase Suspend/Erase Resume Commands
The Erase Suspend command allows the system to in-
terrupt a sector erase operation and then read data
from, or program data to, any sector not selected for
erasure. This command is valid only during the sector
erase operation, including the 50 µs time-out period
during the sector erase command sequence. The
Erase Suspend command is ignored if written during
the chip erase operation or Embedded Program algo-
rithm. Writing the Erase Suspend command during the
Sector Erase time-out immediately terminates the
time-out period and suspends the erase operation. Ad-
dresses are “don’t-cares” when writing the Erase
Suspend command.
When the Erase Suspend command is written during a
sector erase operation, the device requires a maximum
of 20 s to suspend the erase operation. However,
when the Erase Suspend command is written during
the sector erase time-out, the device immediately ter-
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