M50FLW040B ST Microelectronics, M50FLW040B Datasheet - Page 6

• Manufacturer Part Number: M50FLW040B
• Description: 4 Mbit 3V Supply Firmware Hub / Low Pin Count Flash Memory
• Manufacturer: ST Microelectronics

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M50FLW040A, M50FLW040B
SUMMARY DESCRIPTION
The M50FLW040 is a 4 Mbit (512Kb x8) non-vola-
tile memory that can be read, erased and repro-
grammed. These operations can be performed
using a single low voltage (3.0 to 3.6V) supply. For
fast programming and fast erasing in production
lines, an optional 12V power supply can be used
to reduce the erasing and programming time.
The memory is divided into 8 Uniform Blocks of
64 KBytes each, three of which are divided into 16
uniform sectors of 4 KBytes each (see
A.
erased independently. So, it is possible to pre-
serve valid data while old data is erased. Blocks
can be protected individually to prevent accidental
program or erase commands from modifying their
contents.
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 re-
quired to update the memory contents. The end of
a program or erase operation can be detected and
6/52
for details). All blocks and sectors can be
APPENDIX
any error conditions identified. The command set
to control the memory is consistent with the JE-
DEC standards.
Two different bus interfaces are supported by the
memory:
The memory is supplied with all the bits erased
(set to ’1’).
The primary interface, the FWH/LPC
Interface, uses Intel’s proprietary Firmware
Hub (FWH) and Low Pin Count (LPC)
protocol. This has been designed to remove
the need for the ISA bus in current PC
Chipsets. The M50FLW040 acts as the PC
BIOS on the Low Pin Count bus for these PC
Chipsets.
The secondary interface, the Address/
Address Multiplexed (or A/A Mux) Interface, is
designed to be compatible with current Flash
Programmers, for production line
programming prior to fitting the device in a PC
Motherboard.