AM29DL640D120 AMD [Advanced Micro Devices], AM29DL640D120 Datasheet - Page 10

• Manufacturer Part Number: AM29DL640D120
• Description: 64 Megabit CMOS 3.0 Volt-only, Simultaneous Read/Write Flash Memory
• Manufacturer: AMD [Advanced Micro Devices]

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 14 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# to V
For program operations, the BYTE# pin determines
whether the device accepts program data in bytes or
words. Refer to “Word/Byte Configuration” for more
information.
The device features an Unlock Bypass mode to facili-
tate faster programming. Once a bank enters the
Unlock Bypass mode, only two write cycles are re-
quired to program a word or byte, instead of four. The
“Byte/Word Program Command Sequence” section
has details on programming data to the device using
b o t h s t a n d a r d a n d U n l o ck B y p a s s c o m m a n d
sequences.
An erase operation can erase one sector, multiple sec-
tors, or the entire device. Table 2 indicates the address
space that each sector occupies. The device address
space is divided into four banks: Banks 1 and 4 con-
tains the boot/parameter sectors, and Banks 2 and 3
contains the larger, code sectors of uniform size. A
“bank address” is the address bits required to uniquely
select a bank. Similarly, a “sector address” is the ad-
dress bits required to uniquely select a sector. The
“Command Definitions” section has details on erasing
a sector or the entire chip, or suspending/resuming the
erase operation.
I
tive current specification for the write mode. The AC
Characteristics section contains timing specification
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
mode, temporarily unprotects any protected sectors,
and uses the higher voltage on the pin to reduce the
time required for program operations. The system
October 7, 2004
CC1
CC2
in the DC Characteristics table represents the ac-
in the DC Characteristics table represents the ac-
IL
, and OE# to V
HH
IH
on this pin, the device auto-
.
Am29DL640D
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 17 for related
information.
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 Autoselect Mode and Autose-
l e c t C o m m a n d S e q u e n c e s e c t i o n s fo r m o r e
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 21 shows how read and write cycles
may be initiated for simultaneous operation with zero
latency. I
represent the current specifications for read-while-pro-
gram 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# and RESET# pins are both held at V
(Note that this is a more restricted voltage range than
V
V
but the standby current will be greater. The device re-
quires standard access time (t
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.
I
standby current specification.
CC3
HH
IH
CC
.) If CE# and RESET# are held at V
from the WP#/ACC pin returns the device to nor-
± 0.3 V, the device will be in the standby mode,
in the DC Characteristics table represents the
CC6
and I
CC7
in the DC Characteristics table
HH
must not be asserted on
CE
) for read access
IH
, but not within
CC
± 0.3 V.
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