M29W400DT ST Microelectronics, M29W400DT Datasheet - Page 5

• Manufacturer Part Number: M29W400DT
• Description: 4 Mbit (512Kb x8 or 256Kb x16 / Boot Block) 3V Supply Flash Memory
• Manufacturer: ST Microelectronics

SUMMARY DESCRIPTION
The M29W400D is a 4 Mbit (512Kb x8 or 256Kb
x16) non-volatile memory that can be read, erased
and reprogrammed. These operations can be per-
formed using a single low voltage (2.7 to 3.6V)
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 writ-
ten 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
Figure 2. Logic Diagram
A0-A17
RP
W
G
E
18
M29W400DT
M29W400DB
V CC
V SS
15
DQ0-DQ14
DQ15A–1
BYTE
RB
AI06853
command set required to control the memory is
consistent with JEDEC standards.
The blocks in the memory are asymmetrically ar-
ranged, see Figures 6 and 7, Block 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 32K is a small Main Block where the ap-
plication may be stored.
Chip Enable, Output Enable and Write Enable sig-
nals control the bus operation of the memory.
They allow simple connection to most micropro-
cessors, often without additional logic.
The memory is offered in SO44, TSOP48 (12 x
20mm) and TFBGA48 (0.8mm pitch) packages.
The memory is supplied with all the bits erased
(set to ’1’).
Table 1. Signal Names
A0-A17
DQ0-DQ7
DQ8-DQ14
DQ15A–1
E
G
W
RP
RB
BYTE
V
V
NC
CC
SS
Address Inputs
Data Inputs/Outputs
Data Inputs/Outputs
Data Input/Output or Address Input
Chip Enable
Output Enable
Write Enable
Reset/Block Temporary Unprotect
Ready/Busy Output
(not available on SO44 package)
Byte/Word Organization Select
Supply Voltage
Ground
Not Connected Internally
M29W400DT, M29W400DB
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