AM29F200AB-120EC AMD [Advanced Micro Devices], AM29F200AB-120EC Datasheet - Page 8

• Manufacturer Part Number: AM29F200AB-120EC
• Description: 2 Megabit (256 K x 8-Bit/128 K x 16-Bit) CMOS 5.0 Volt-only, Boot Sector Flash Memory
• Manufacturer: AMD [Advanced Micro Devices]

DEVICE BUS OPERATIONS
This section describes the requirements and use of the
device bus operations, which are initiated through the
internal command register. The command register itself
does not occupy any addressable memory location.
The register is composed of latches that store the com-
mands, along with the address and data information
needed to execute the command. The contents of the
Legend:
L = Logic Low = V
Note: See the sections on Sector Protection and Temporary Sector Unprotect for more information.
Word/Byte Configuration
The BYTE# pin controls whether the device data I/O
pins DQ15–DQ0 operate in the byte or word configura-
tion. If the BYTE# pin is set at logic ‘1’, the device is in
word configuration, DQ15–DQ0 are active and con-
trolled by CE# and OE#.
If the BYTE# pin is set at logic ‘0’, the device is in byte
configuration, and only data I/O pins DQ0–DQ7 are ac-
tive and controlled by CE# and OE#. The data I/O pins
DQ8–DQ14 are tri-stated, and the DQ15 pin is used as
an input for the LSB (A-1) address function.
Requirements for Reading Array Data
To read array data from the outputs, the system must
drive the CE# and OE# pins to V
control and selects the device. OE# is the output control
and gates array data to the output pins. WE# should re-
main at V
determines whether the device outputs array data in
words or bytes.
The internal state machine is set for reading array
data upon device power-up, or after a hardware re-
set. This ensures that no spurious alteration of the
8
Read
Write
CMOS Standby
TTL Standby
Output Disable
Hardware Reset
Temporary Sector Unprotect
(See Note)
IH
Operation
. On x16 (word-wide) devices, the BYTE# pin
IL
, H = Logic High = V
V
CC
Table 1. Am29F200A Device Bus Operations
IL
CE#
. CE# is the power
± 0.5 V
IH
H
X
X
L
L
L
, V
ID
= 12.0 0.5 V, X = Don’t Care, D
P R E L I M I N A R Y
OE#
H
X
X
H
X
X
L
Am29F200A
WE#
H
X
X
H
X
X
L
V
register serve as inputs to the internal state machine.
The state machine outputs dictate the function of the
device. The appropriate device bus operations table
lists the inputs and control levels required, and the re-
sulting output. The following subsections describe
each of these operations in further detail.
memory content occurs during the power transition.
No command 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. The
device remains enabled for read access until the
command register contents are altered.
See “Reading Array Data” for more information. Refer
to the AC Read Operations table for timing specifica-
tions and to the Read Operations Timings diagram for
the timing waveforms. I
table represents the active 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
On x16 (word-wide) devices, for program operations,
the BYTE# pin determines whether the device ac-
cepts program data in bytes or words. Refer to
“Word/Byte Configuration” for more information.
RESET#
CC
V
± 0.5 V
H
H
H
H
L
ID
IL
, and OE# to V
IN
= Data In, D
A0–A16
A
A
A
X
X
X
X
IN
IN
IN
CC1
OUT
DQ0–DQ7
IH
High-Z
High-Z
High-Z
High-Z
.
D
= Data Out, A
in the DC Characteristics
D
D
OUT
IN
IN
BYTE#
High-Z
High-Z
High-Z
High-Z
= V
D
D
D
DQ8–DQ15
OUT
IN
IN
IN
IH
= Address In
BYTE#
High-Z
High-Z
High-Z
High-Z
High-Z
High-Z
= V
X
IL