m29f800at STMicroelectronics, m29f800at Datasheet - Page 6

• Manufacturer Part Number: m29f800at
• Description: 8 Mbit 1mb X8 Or 512kb X16, Boot Block Single Supply Flash Memory
• Manufacturer: STMicroelectronics

M29F800AT, M29F800AB
dress Inputs. The Address Inputs are latched by
the Command Interface on the falling edge of Chip
Enable or Write Enable, whichever occurs last.
The Data Inputs/Outputs are latched by the Com-
mand Interface on the rising edge of Chip Enable
or Write Enable, whichever occurs first. Output En-
able must remain High, V
Write operation. See Figures 8 and 9, Write AC
Waveforms, and Tables 12 and 13, Write AC
Characteristics, for details of the timing require-
ments.
Output Disable. The Data Inputs/Outputs are in
the high impedance state when Output Enable is
High, V
Standby. When Chip Enable is High, V
Data Inputs/Outputs pins are placed in the high-
impedance state and the Supply Current is re-
duced to the Standby level.
When Chip Enable is at V
reduced to the TTL Standby Supply Current, I
To further reduce the Supply Current to the CMOS
Standby Supply Current, I
be held within V
levels see Table 10, DC Characteristics.
During program or erase operations the memory
will continue to use the Program/Erase Supply
Current, I
til the operation completes.
Automatic Standby. If CMOS levels (V
are used to drive the bus and the bus is inactive for
150ns or more the memory enters Automatic
Standby where the internal Supply Current is re-
duced to the CMOS Standby Supply Current, I
The Data Inputs/Outputs will still output data if a
Bus Read operation is in progress.
Special Bus Operations
Additional bus operations can be performed to
read the Electronic Signature and also to apply
and remove Block Protection. These bus opera-
tions are intended for use by programming equip-
ment and are not usually used in applications.
They require V
Electronic Signature. The memory has two
codes, the manufacturer code and the device
code, that can be read to identify the memory.
These codes can be read by applying the signals
listed in Tables 4A and 4B, Bus Operations.
Block Protection and Blocks Unprotection. Each
block can be separately protected against acci-
dental Program or Erase. Protected blocks can be
unprotected to allow data to be changed. Block
Protection and Block Unprotection operations
must only be performed on programming equip-
ment.
For further information refer to Application Note
AN1122, Applying Protection and Unprotection to
M29 Series Flash.
6/21
IH
.
CC4
, for Program or Erase operations un-
ID
CC
to be applied to some pins.
0.2V. For Standby current
IH
CC3
IH
, during the whole Bus
the Supply Current is
, Chip Enable should
CC
IH
0.2V)
, the
CC2
CC3
.
.
COMMAND INTERFACE
All Bus Write operations to the memory are inter-
preted by the Command Interface. Commands
consist of one or more sequential Bus Write oper-
ations. Failure to observe a valid sequence of Bus
Write operations will result in the memory return-
ing to Read mode. In this case, after at least 50ns,
an address transition or Chip Enable going Low is
required before reading correct data. The long
command sequences are imposed to maximize
data security.
The address used for the commands changes de-
pending on whether the memory is in 16-bit or 8-
bit mode. See either Table 5A, or 5B, depending
on the configuration that is being used, for a sum-
mary of the commands.
Read/Reset Command. The Read/Reset com-
mand returns the memory to its Read mode where
it behaves like a ROM or EPROM. It also resets
the errors in the Status Register. Either one or
three Bus Write operations can be used to issue
the Read/Reset command.
If the Read/Reset command is issued during a
Block Erase operation or following a Programming
or Erase error then the memory will take up to 10
to abort. During the abort period no valid data can
be read from the memory. Issuing a Read/Reset
command during a Block Erase operation will
leave invalid data in the memory.
Auto Select Command. The Auto Select com-
mand is used to read the Manufacturer Code, the
Device Code and the Block Protection Status.
Three consecutive Bus Write operations are re-
quired to issue the Auto Select command. Once
the Auto Select command is issued the memory
remains in Auto Select mode until another com-
mand is issued.
From the Auto Select mode the Manufacturer
Code can be read using a Bus Read operation
with A0 = V
may be set to either V
Code for STMicroelectronics is 0020h.
The Device Code can be read using a Bus Read
operation with A0 = V
address bits may be set to either V
Device Code for the M29F800AT is 00ECh and for
the M29F800AB is 0058h.
The Block Protection Status of each block can be
read using a Bus Read operation with A0 = V
A1 = V
the block. The other address bits may be set to ei-
ther V
then 01h is output on Data Inputs/Outputs DQ0-
DQ7, otherwise 00h is output.
Program Command. The Program command
can be used to program a value to one address in
the memory array at a time. The command re-
IL
IH
or V
, and A12-A18 specifying the address of
IL
IH
and A1 = V
. If the addressed block is protected
IL
IH
or V
IL
and A1 = V
. The other address bits
IH
. The Manufacturer
IL
IL
or V
. The other
IH
. The
IL
s
,