|A29L004||512K X 8 Bit CMOS 3.0 Volt-only, Boot Sector Flash Memory|
|A29L004 Datasheet PDF : 39 Pages |
can be re-enabled after the last Sector Erase command is
written. If the time between additional sector erase commands
can be assumed to be less than 50µs, the system need not
monitor I/O3. Any command other than Sector Erase or Erase
Suspend during the time-out period resets the device to
reading array data. The system must rewrite the command
sequence and any additional sector addresses and
The system can monitor I/O3 to determine if the sector erase
timer has timed out. (See the " I/O3: Sector Erase Timer"
section.) The time-out begins from the rising 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.
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 status of the erase
operation by using I/O7, I/O6, or I/O2. Refer to "Write
Operation Status" for information on these status bits.
4 illustrates the algorithm for the erase operation. 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 interrupt
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
50µs 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
algorithm. Writing the Erase Suspend command during the
Sector Erase time-out immediately terminates the time-out
period and suspends the erase operation. Addresses 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 20µs to
suspend the erase operation. However, when the Erase
Suspend command is written during the sector erase time-
out, the device immediately terminates the time-out period
and suspends the erase operation.
After the erase operation has been suspended, the system
can read array data from or program data to any sector not
selected for erasure. (The device "erase suspends" all sectors
selected for erasure.) Normal read and write timings and
command definitions apply. Reading at any address within
erase-suspended sectors produces status data on I/O7 - I/O0.
The system can use I/O7, or I/O6 and I/O2 together, to
determine if a sector is actively erasing or is erase-
suspended. See "Write Operation Status" for information on
these status bits.
After an erase-suspended program operation is complete, the
system can once again read array data within non-suspended
sectors. The system can determine the status of the program
operation using the I/O7 or I/O6 status bits, just as in the
standard program operation. See "Write Operation Status" for
The system may also write the autoselect command
sequence when the device is in the Erase Suspend mode.
The device allows reading autoselect codes even at
addresses within erasing sectors, since the codes are not
stored in the memory array. When the device exits the
autoselect mode, the device reverts to the Erase Suspend
mode, and is ready for another valid operation. See
"Autoselect Command Sequence" for more information.
The system must write the Erase Resume command (address
bits are "don't care") to exit the erase suspend mode and
continue the sector erase operation. Further writes of the
Resume command are ignored. Another Erase Suspend
command can be written after the device has resumed
Data = FFh ?
1. See the appropriate Command Definitions table for erase
2. See "I/O3 : Sector Erase Timer" for more information.
Figure 4. Erase Operation
PRELIMINARY (October, 2002, Version 0.0)
AMIC Technology, Corp.
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