MT28F004B3VG-10TET Micron, MT28F004B3VG-10TET Datasheet - Page 7

• Manufacturer Part Number: MT28F004B3VG-10TET
• Description: 4Mb SMART 3 BOOT BLOCK FLASH MEMORY
• Manufacturer: Micron

FUNCTIONAL DESCRIPTION
corporate a number of features ideally suited for system
firmware. The memory array is segmented into indi-
vidual erase blocks. Each block may be erased without
affecting data stored in other blocks. These memory
blocks are read, written and erased with commands to
the command execution logic (CEL). The CEL controls
the operation of the internal state machine (ISM), which
completely controls all WRITE, BLOCK ERASE and VERIFY
operations. The ISM protects each memory location from
over-erasure and optimizes each memory location for
maximum data retention. In addition, the ISM greatly
simplifies the control necessary for writing the device in-
system or in an external programmer.
mation on the operation of the MT28F004B3 and
MT28F400B3 and is organized into these sections:
OVERVIEW
SMART 3 TECHNOLOGY (B3)
system READ, WRITE and ERASE operations. WRITE and
ERASE operations may be executed with a V
3.3V or 5V. Due to process technology advances, 5V V
optimal for application and production programming.
SEVEN INDEPENDENTLY ERASABLE MEMORY
BLOCKS
seven independently erasable memory blocks that allow
portions of the memory to be erased without affecting the
rest of the memory data. A special boot block is hard-
ware-protected against inadvertent erasure or writing by
requiring either a super-voltage on the RP# pin or driving
the WP# pin HIGH. One of these two conditions must
exist along with the V
before a WRITE or ERASE is performed on the boot block.
The remaining blocks require only the V
present on the V
4Mb Smart 3 Boot Block Flash Memory
F45_2.p65 – Rev. 2, Pub. 3/01
The MT28F004B3 and MT28F400B3 Flash devices in-
The Functional Description provides detailed infor-
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Smart 3 technology allows maximum flexibility for in-
The MT28F004B3 and MT28F400B3 are organized into
Overview
Memory Architecture
Output (READ) Operations
Input Operations
Command Set
ISM Status Register
Command Execution
Error Handling
WRITE/ERASE Cycle Endurance
Power Usage
Power-Up
PP
pin before writing or erasing.
PP
voltage (3.3V or 5V) on the V
PP
PP
voltage be
voltage of
PP
SMART 3 BOOT BLOCK FLASH MEMORY
PP
pin
is
7
HARDWARE-PROTECTED BOOT BLOCK
written only when the RP# pin is taken to V
WP# pin is brought HIGH. This provides additional secu-
rity for the core firmware during in-system firmware
updates should an unintentional power fluctuation or
system reset occur. The MT28F004B3 and MT28F400B3
are available with the boot block starting at the bottom of
the address space (“B” suffix) or the top of the address
space (“T” suffix).
SELECTABLE BUS SIZE (MT28F400B3 ONLY)
(512K x 8) or 16-bit (256K x 16) data bus for reading and
writing the memory. The BYTE# pin is used to select the
bus width. In the x16 configuration, control data is read
or written only on the lower eight bits (DQ0–DQ7).
data pins for the selected configuration. When the x8
configuration is selected, data is written in byte form;
when the x16 configuration is selected, data is written in
word form.
INTERNAL STATE MACHINE (ISM)
simplified with an ISM that controls all erase and write
algorithms in the memory array. The ISM ensures protec-
tion against overerasure and optimizes write margin to
each cell.
crements and monitors WRITE attempts, verifies write
margin on each memory cell and updates the ISM status
register. When BLOCK ERASE is performed, the ISM
automatically overwrites the entire addressed block
(eliminates overerasure), increments and monitors
ERASE attempts, and sets bits in the ISM status register.
ISM STATUS REGISTER
to monitor the status of the ISM during WRITE and ERASE
operations. Two bits of the 8-bit status register are set and
cleared entirely by the ISM. These bits indicate whether
the ISM is busy with a WRITE or ERASE task and when an
ERASE has been suspended. Additional error informa-
tion is set in three other bits: V
erase status.
COMMAND EXECUTION LOGIC (CEL)
device. These commands control the operation of the
ISM and the read path (i.e., memory array, ID register or
status register). Commands may be issued to the CEL
while the ISM is active. However, there are restrictions on
This block of the memory array can be erased or
The MT28F400B3 allows selection of an 8-bit
Data written to the memory array utilizes all active
BLOCK ERASE and BYTE/WORD WRITE timing are
During WRITE operations, the ISM automatically in-
The ISM status register enables an external processor
The CEL receives and interprets commands to the
Micron Technology, Inc., reserves the right to change products or specifications without notice.
PP
status, write status and
©2001, Micron Technology, Inc.
HH
or when the
4Mb