November 24, 2003
Am70PDL127CDH/Am70PDL129CDH
17
A D V A N C E I N F O R M A T I O N
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#f1 or CE#f2 (PDL 129 only) to V
IL
, and OE# to V
IH
.
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, instead of four. The “Word Pro-
gram Command Sequence” section has details on
programming data to the device using both standard
and Unlock Bypass command sequences.
An erase operation can erase one sector, multiple sec-
tors, or the entire device.
Table 4
indicates the address
space that each sector occupies. A “bank address” is
the address bits required to uniquely select a bank.
Similarly, a “sector address” refers to the address 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 op-
eration.
I
CC2
in the DC Characteristics table represents the ac-
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 function is primarily in-
tended to allow faster manufacturing throughput at the
factory.
If the system asserts V
HH
on this pin, the device auto-
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
would use a two-cycle program command sequence
as required by the Unlock Bypass mode. Removing
V
HH
from the WP#/ACC pin returns the device to nor-
mal operation. Note that V
HH
must not be asserted on
WP#/ACC for operations other than accelerated pro-
gramming, or device damage may result. In addition,
the WP#/ACC pin should be raised to V
CC
when not in
use. That is, the WP#/ACC pin should not be left float-
ing or unconnected; inconsistent behavior of the de-
vice may result.
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 Command Se-
quence sections for more information.
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#f1, CE#f2 (PDL129 only) and RESET# pins are all
held at V
IO
± 0.3 V. (Note that this is a more restricted
voltage range than V
IH
.) If CE#f1, CE#f2 (PDL129
only), and RESET# are held at V
IH
, but not within V
CC
± 0.3 V, the device will be in the standby mode, but the
standby current will be greater. The device requires
standard access time (t
CE
) for read access 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.
ICC3 in the DC Characteristics table represents the
CMOS standby current specification.
Automatic Sleep Mode
The automatic sleep mode minimizes Flash device en-
ergy consumption. The device automatically enables
this mode when addresses remain stable for t
ACC
+
150 ns. The automatic sleep mode is independent of
the CE#f1/CE#f2 (PDL129 only), WE#, and OE# con-
trol signals. Standard address access timings provide
new data when addresses are changed. While in
sleep mode, output data is latched and always avail-
able to the system. Note that during automatic sleep
mode, OE# must be at V
IH
before the device reduces
current to the stated sleep mode specification. ICC5 in
the DC Characteristics table represents the automatic
sleep mode current specification.