MBM29DL34TF/BF are organized into two physical banks; Bank 1 and Bank 2, which can be considered to be
two separate memory arrays as far as certain operations are concerned. This device is the same as Fujitsu’s
standard 3 V only Flash memories with the additional capability of allowing a normal non-delayed read access
from a non-busy bank of the array while an embedded write (either a program or an erase) operation is simul-
taneously taking place on the other bank.
In the device, a design concept called Sliding Bank Architecture is implemented. Using this concept the device
can execute simultaneous operation between Bank 1 and Bank 2(Refer to “1. Simultaneous Operation” in
“s FUNCTIONAL DESCRIPTION”.).
The standard device offers access times 70 ns allowing operation of high-speed microprocessors without the
wait. To eliminate bus contention the device has separate chip enable (CE) , write enable (WE) and output enable
The MBM29DL34TF/BF support pin and command set compatible with JEDEC standard E2PROMs. Commands
are written to the command register using standard microprocessor write timings. Register contents serve as
input to an internal state-machine which controls the erase and programming circuitry. Write cycles also internally
latch addresses and data needed for the programming and erase operations. Reading data out of the device is
similar to reading from 5.0 V and 12.0 V Flash or EPROM devices.
The device is programmed by executing the program command sequence. This will invoke the Embedded
Program AlgorithmTM which is an internal algorithm that automatically times the program pulse widths and verifies
proper cell margin. Typically each sector can be programmed and verified in about 0.5 seconds. Erase is
accomplished by executing the erase command sequence. This will invoke the Embedded Erase AlgorithmTM
which is an internal algorithm that automatically preprograms the array if it is not already programmed before
executing the erase operation. During erase, the device automatically times the erase pulse widths and verifies
the proper cell margin.
Each sector is typically erased and verified in 0.5 second (if already completely preprogrammed) .
The device also features a sector erase architecture. The sector mode allows each sector to be erased and
reprogrammed without affecting other sectors. The device is erased when shipped from the factory.
The device features single 3.0 V power supply operation for both read and write functions. Internally generated
and regulated voltages are provided for the program and erase operations. A low VCC detector automatically
inhibits write operations on the loss of power. The end of program or erase is detected by Data Polling of DQ7,
by the Toggle Bit feature on DQ6, or the RY/BY output pin. Once the end of a program or erase cycle has been
completed, the device internally return to the read mode.
The device also has a hardware RESET pin. When this pin is driven low, execution of any Embedded Program
Algorithm or Embedded Erase Algorithm is terminated. The internal state machine is then reset to the read
mode. The RESET pin may be tied to the system reset circuitry. Therefore if a system reset occurs during the
Embedded ProgramTM * Algorithm or Embedded EraseTM * Algorithm, the device is automatically reset to the
read mode and have erroneous data stored in the address locations being programmed or erased. These
locations need rewriting after the Reset. Resetting the device enables the system’s microprocessor to read the
boot-up firmware from the Flash memory.
Fujitsu’s Flash technology combines years of Flash memory manufacturing experience to produce the highest
levels of quality, reliability, and cost effectiveness. The device memory electrically erases the entire chip or all
bits within a sector simultaneously via Fowler-Nordhiem tunneling. The bytes/words are programmed one byte/
word at a time using the EPROM programming mechanism of hot electron injection.
*: Embedded EraseTM and Embedded ProgramTM are trademarks of Advanced Micro Devices, Inc.