参数资料
型号: Am29F400BT-90FIB
厂商: Advanced Micro Devices, Inc.
英文描述: 4 Megabit (512 K x 8-Bit/256 K x 16-Bit) CMOS 5.0 Volt-only Boot Sector Flash Memory
中文描述: 4兆位(512亩x 8-Bit/256亩x 16位),5.0伏的CMOS只引导扇区闪存
文件页数: 11/37页
文件大小: 238K
代理商: AM29F400BT-90FIB
Am29F400B
11
P R E L I M I N A R Y
spurious system level signals during V
CC
power-up and
power-down transitions, or from system noise.
Low V
CC
Write Inhibit
When V
CC
is less than V
LKO
, the device does not ac-
cept any write cycles. This protects data during V
CC
power-up and power-down. The command register and
all internal program/erase circuits are disabled, and the
device resets. Subsequent writes are ignored until V
CC
is greater than V
LKO
. The system must provide the
proper signals to the control pins to prevent uninten-
tional writes when V
CC
is greater than V
LKO
.
Write Pulse “Glitch” Protection
Noise pulses of less than 5 ns (typical) on OE#, CE# or
WE# do not initiate a write cycle.
Logical Inhibit
Write cycles are inhibited by holding any one of OE# =
V
IL
, CE# = V
IH
or WE# = V
IH
. To initiate a write cycle,
CE# and WE# must be a logical zero while OE# is a
logical one.
Power-Up Write Inhibit
If WE# = CE# = V
IL
and OE# = V
IH
during power up, the
device does not accept commands on the rising edge
of WE#. The internal state machine is automatically
reset to reading array data on power-up.
COMMAND DEFINITIONS
Writing specific address and data commands or se-
quences into the command register initiates device op-
erations. Table 5 defines the valid register command
sequences. Writing
incorrect
address and data val-
ues
or writing them in the
improper sequence
resets
the device to reading array data.
All addresses are latched on the falling edge of WE# or
CE#, whichever happens later. All data is latched on
the rising edge of WE# or CE#, whichever happens
first. Refer to the appropriate timing diagrams in the
“AC Characteristics” section.
Reading Array Data
The device is automatically set to reading array data
after device power-up. No commands are required to
retrieve data. The device is also ready to read array
data after completing an Embedded Program or Em-
bedded Erase algorithm.
After the device accepts an Erase Suspend command,
the device enters the Erase Suspend mode. The sys-
tem can read array data using the standard read tim-
ings, except that if it reads at an address within erase-
suspended sectors, the device outputs status data.
After completing a programming operation in the Erase
Suspend mode, the system may once again read array
data with the same exception. See “Erase Sus-
pend/Erase Resume Commands” for more information
on this mode.
The system
must
issue the reset command to re-ena-
ble the device for reading array data if DQ5 goes high,
or while in the autoselect mode. See the “Reset Com-
mand” section, next.
See also “Requirements for Reading Array Data” in the
“Device Bus Operations” section for more information.
The Read Operations table provides the read parame-
ters, and Figure 9 shows the timing diagram.
Reset Command
Writing the reset command to the device resets the de-
vice to reading array data. Address bits are don’t care
for this command.
The reset command may be written between the se-
quence cycles in an erase command sequence before
erasing begins. This resets the device to reading array
data. Once erasure begins, however, the device ig-
nores reset commands until the operation is complete.
The reset command may be written between the se-
quence cycles in a program command sequence be-
fore programming begins. This resets the device to
reading array data (also applies to programming in
Erase Suspend mode). Once programming begins,
however, the device ignores reset commands until the
operation is complete.
The reset command may be written between the se-
quence cycles in an autoselect command sequence.
Once in the autoselect mode, the reset command
must
be written to return to reading array data (also applies
to autoselect during Erase Suspend).
If DQ5 goes high during a program or erase operation,
writing the reset command returns the device to read-
ing array data (also applies during Erase Suspend).
Autoselect Command Sequence
The autoselect command sequence allows the host
system to access the manufacturer and devices codes,
and determine whether or not a sector is protected.
Table 5 shows the address and data requirements. This
method is an alternative to that shown in Table 4, which
is intended for PROM programmers and requires V
ID
on address bit A9.
The autoselect command sequence is initiated by
writing two unlock cycles, followed by the autoselect
command. The device then enters the autoselect
mode, and the system may read at any address any
相关PDF资料
PDF描述
AM29F400BT-90SC 4 Megabit (512 K x 8-Bit/256 K x 16-Bit) CMOS 5.0 Volt-only Boot Sector Flash Memory
Am29F400BT-90SCB 4 Megabit (512 K x 8-Bit/256 K x 16-Bit) CMOS 5.0 Volt-only Boot Sector Flash Memory
AM29F400BT-90SE 4 Megabit (512 K x 8-Bit/256 K x 16-Bit) CMOS 5.0 Volt-only Boot Sector Flash Memory
AM29F400BT-90SEB 4 Megabit (512 K x 8-Bit/256 K x 16-Bit) CMOS 5.0 Volt-only Boot Sector Flash Memory
AM29F400BT-90SI 4 Megabit (512 K x 8-Bit/256 K x 16-Bit) CMOS 5.0 Volt-only Boot Sector Flash Memory
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AM29F400BT-90SF\\T 制造商:Spansion 功能描述:NOR Flash Parallel 5V 4Mbit 512K/256K x 8bit/16bit 90ns 44-Pin SO T/R
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AM29F400BT-90SI 制造商:Spansion 功能描述:
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