AM49DL6408H55FS SPANSION [SPANSION], AM49DL6408H55FS Datasheet - Page 12

• Manufacturer Part Number: AM49DL6408H55FS
• Description: 64 Megabit (4 M x 16-Bit) CMOS 3.0 Volt-only, Simultaneous Operation Flash Memory and 8 Mbit (512 K x 16-Bit)
• Manufacturer: SPANSION [SPANSION]

Requirements for Reading Array Data
To read array data from the outputs, the system must
drive the CE#f and OE# pins to V
control and selects the device. OE# is the output con-
trol and gates array data to the output pins. WE#
should remain at V
The internal state machine is set for reading array data
upon device power-up, or after a hardware reset. This
ensures that no spurious alteration of the memory
content occurs during the power transition. No com-
mand is necessary in this mode to obtain array data.
Standard microprocessor read cycles that assert valid
addresses on the device address inputs produce valid
data on the device data outputs. Each bank remains
enabled for read access until the command register
contents are altered.
Refer to the AC Read-Only Operations table for timing
specifications and to Figure 15 for the timing diagram.
I
tive current specification for reading array data.
Writing Commands/Command Sequences
To write a command or command sequence (which in-
cludes programming data to the device and erasing
sectors of memory), the system must drive WE# and
CE#f to V
The device features an Unlock Bypass mode to facili-
tate faster programming. Once a bank enters the Un-
lock Bypass mode, only two write cycles are required
to program a word or byte, instead of four.
An erase operation can erase one sector, multiple sec-
tors, or the entire device. Table 2 indicates the address
space that each sector occupies. Similarly, a “sector
address” is the address bits required to uniquely select
a sector. The “Flash Command Definitions” section
has details on erasing a sector or the entire chip, or
suspending/resuming the erase operation.
The device address space is divided into four banks. A
“bank address” is the address bits required to uniquely
select a bank.
I
tive current specification for the write mode. The Flash
AC Characteristics section contains timing specifica-
tion tables and timing diagrams for write operations.
Accelerated Program Operation
The device offers accelerated program operations
through the ACC function. This is one of two functions
provided by the WP#/ACC pin. This function is prima-
rily intended to allow faster manufacturing throughput
at the factory.
If the system asserts V
matically enters the aforementioned Unlock Bypass
10
CC1
CC2
in the DC Characteristics table represents the ac-
in the DC Characteristics table represents the ac-
IL
, and OE# to V
IH
.
HH
IH
on this pin, the device auto-
.
A D V A N C E
IL
. CE#f is the power
Am49DL6408H
I N F O R M A T I O N
mode, temporarily unprotects any protected sectors,
and uses the higher voltage on the pin to reduce the
time required for program operations. The system
would use a two-cycle program command sequence
as required by the Unlock Bypass mode. Removing
V
mal operation. Note that V
WP#/ACC for operations other than accelerated pro-
gramming, or device damage may result. In addition,
the WP#/ACC pin must not be left floating or uncon-
nected; inconsistent behavior of the device may result.
See “Write Protect (WP#)” on page 16 for related infor-
mation.
Autoselect Functions
If the system writes the autoselect command se-
quence, the device enters the autoselect mode. The
system can then read autoselect codes from the inter-
nal register (which is separate from the memory array)
on DQ15–DQ0. Standard read cycle timings apply in
this mode. Refer to the Sector/Sector Block Protection
and Unprotection and Autoselect Command Se-
quence sections for more information.
Simultaneous Read/Write Operations with
Zero Latency
This device is capable of reading data from one bank
of memory while programming or erasing in the other
bank of memory. An erase operation may also be sus-
pended to read from or program to another location
within the same bank (except the sector being
erased). Figure 20 shows how read and write cycles
may be initiated for simultaneous operation with zero
latency. I
rent specifications for read-while-program and
read-while-erase, respectively.
Standby Mode
When the system is not reading or writing to the de-
vice, it can place the device in the standby mode. In
this mode, current consumption is greatly reduced,
and the outputs are placed in the high impedance
state, independent of the OE# input.
The device enters the CMOS standby mode when the
CE#f and RESET# pins are both held at V
(Note that this is a more restricted voltage range than
V
within V
mode, but the standby current will be greater. The de-
vice requires standard access time (t
cess when the device is in either of these standby
modes, before it is ready to read data.
If the device is deselected during erasure or program-
ming, the device draws active current until the
operation is completed.
HH
IH
.) If CE#f and RESET# are held at V
from the WP#/ACC pin returns the device to nor-
CC
CC6
± 0.3 V, the device will be in the standby
f and I
CC7
f in the table represent the cur-
HH
must not be asserted on
March 12, 2004
CE
) for read ac-
CC
IH
, but not
± 0.3 V.