m29w400db STMicroelectronics, m29w400db Datasheet - Page 6

• Manufacturer Part Number: m29w400db
• Description: 4 Mbit 512kb X8 Or 256kb X16, Boot Block 3v Supply Flash Memory
• Manufacturer: STMicroelectronics

Description
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Description
The M29W400D is a 4 Mbit (512 Kb x 8 or 256 Kb x 16) non-volatile memory that can be
read, erased and reprogrammed. These operations can be performed using a single low
voltage (2.7 to 3.6 V) supply. On power-up the memory defaults to its Read mode where it
can be read in the same way as a ROM or EPROM.
The memory is divided into blocks that can be erased independently so it is possible to
preserve valid data while old data is erased. Each block can be protected independently to
prevent accidental Program or Erase commands from modifying the memory. Program and
Erase commands are written to the command interface of the memory. An on-chip
Program/Erase controller simplifies the process of programming or erasing the memory by
taking care of all of the special operations that are required to update the memory contents.
The end of a program or erase operation can be detected and any error conditions
identified. The command set required to control the memory is consistent with JEDEC
standards.
The blocks in the memory are asymmetrically arranged, see
addresses. The first or last 64 Kbytes have been divided into four additional blocks. The
16 Kbyte boot block can be used for small initialization code to start the microprocessor, the
two 8 Kbyte parameter blocks can be used for parameter storage and the remaining
32 Kbyte is a small main block where the application may be stored.
Chip Enable, Output Enable and Write Enable signals control the bus operation of the
memory. They allow simple connection to most microprocessors, often without additional
logic.
The memory is offered in SO44, TSOP48 (12 x 20 mm), TFBGA48 0.8 mm pitch (6 x 9 mm
and 6 x 8 mm) packages. The memory is supplied with all the bits erased (set to ’1’).
In order to meet environmental requirements, ST offers the M29W400D in ECOPACK
packages. ECOPACK packages are Lead-free. The category of second level interconnect is
marked on the package and on the inner box label, in compliance with JEDEC Standard
JESD97. The maximum ratings related to soldering conditions are also marked on the inner
box label. ECOPACK is an ST trademark. ECOPACK specifications are available at:
www.st.com.
Figure 5
M29W400DT, M29W400DB
and
Figure
6, Block
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