am41pds3224d Meet Spansion Inc., am41pds3224d Datasheet - Page 13

• Manufacturer Part Number: am41pds3224d
• Description: 32 Mbit 2 M ? 16-bit Cmos 1.8 Volt-only, Simultaneous Operation Page Mode Flash Memory And 4 Mbit 512 K ? 8-bit/256 K ? 16-bit Static Ram Preliminary
• Manufacturer: Meet Spansion Inc.

FLASH DEVICE BUS OPERATIONS
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.
See “Requirements for Reading Array Data” for more
information. Refer to the AC Read-Only Operations
table for timing specifications and to Figure 15 for the
timing diagram. I
represents the active current specification for reading
array data.
Read Mode
Random Read (Non-Page Mode Read)
The device has two control functions which must be
satisfied in order to obtain data at the outputs. CE# is
the power control and should be used for device selec-
tion. OE# is the output control and should be used to
gate data to the output pins if the device is selected.
Address access time (t
stable addresses to valid output data. The chip enable
access time (t
dresses and stable CE# to valid data at the output
pins. The output enable access time is the delay from
the falling edge of OE# to valid data at the output pins
(assuming the addresses have been stable for at least
t
Page Mode Read
The device is capable of fast Page mode read and is
compatible with the Page mode Mask ROM read oper-
ation. This mode provides faster read access speed
for random locations within a page. The Page size of
the device is 4 words. The appropriate Page is se-
lected by the higher address bits A20–A0 and the LSB
bits A1–A0 determine the specific word within that
page. This is an asynchronous operation with the mi-
croprocessor supplying the specific word location.
The random or initial page access is equal to t
t
the locations specified by the microprocessor fall
12
ACC
CE
and subsequent Page read accesses (as long as
–t
OE
time).
CE
CC1
) is the delay from the stable ad-
IH
.
in the DC Characteristics table
ACC
) is equal to the delay from
IL
. CE#f is the power
P R E L I M I N A R Y
ACC
Am41PDS3224D
or
within that Page) are equivalent to t
deasserted and reasserted for a subsequent access,
the access time is t
the device and OE# is the output control and should be
used to gate data to the output pins if the device is se-
lected. Fast Page mode accesses are obtained by
keeping A20–A2 constant and changing A1–A0 to se-
lect the specific word within that page. See Figure 16
for timing specifications.
The following table determines the specific word within
the selected page:
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
The device features an Unlock Bypass mode to facil-
itate faster programming. Once the device enters the
Unlock Bypass mode, only two write cycles are re-
quired to program a word, instead of four. The “Word
Program 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 3 indicates the address
space that each sector occupies.
I
tive current specification for the write mode. The Mea-
surements performed by placing a 50
the data pin with a bias of V
high to the data bus driven to V
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,
CC2
f in the DC Characteristics table represents the ac-
Word 0
Word 1
Word 2
Word 3
IL
Word
, and OE# to V
Table 3. Page Word Mode
ACC
or t
HH
IH
on this pin, the device auto-
CE
.
. Here again, CE# selects
CC
A1
/2. The time from OE#
0
0
1
1
CC
/2 is taken as t
PACC
. When CE# is
termination on
May 13, 2002
A0
0
1
0
1
DF
AC