AM29F100B-90FI データシートの表示（PDF） - Advanced Micro Devices
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AM29F100B-90FI
Advanced Micro Devices
AM29F100B-90FI Datasheet PDF : 37 Pages
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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 it-
self does not occupy any addressable memory
location. The register is composed of latches that store
the commands, along with the address and data infor-
mation needed to execute the command. The contents
of the register serve as inputs to the internal state ma-
chine. 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
resulting output. The following subsections describe
each of these operations in further detail.
Table 1. Am29F100 Device Bus Operations
Operation
Read
Write
Standby
Output Disable
Hardware Reset
Temporary Sector
Unprotect
CE#
OE# WE# RESET#
L
LH
H
L
HL
H
VCC ± 0.5 V X
L
H
X VCC ± 0.5 V
H
H
X
XX
L
Addresses
(Note 1)
AIN
AIN
X
X
X
X
XX
VID
AIN
DQ8–DQ15
DQ0–
DQ7
DOUT
DIN
High-Z
BYTE#
= VIH
BYTE#
= VIL
DOUT
DIN
DQ8–DQ14 = High-Z,
DQ15 = A-1
High-Z
High-Z
High-Z High-Z
High-Z
High-Z High-Z
High-Z
DIN
DIN
High-Z
Legend:
L = Logic Low = VIL, H = Logic High = VIH, VID = 12.0 ± 0.5 V, X = Don’t Care, AIN = Addresses In, DIN = Data In, DOUT = Data Out
Notes:
1. Addresses are A15:A0 in word mode (BYTE# = VIH), A15:A-1 in byte mode (BYTE# = VIL).
2. The sector protect and sector unprotect functions must be implemented via programming equipment. See the “Sector Pro-
tection/Unprotection” section.
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 VIL. CE# is the power
control and selects the device. OE# is the output con-
trol and gates array data to the output pins. WE# should
remain at VIH. The BYTE# pin 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 reset. This
ensures that no spurious alteration of the memory con-
tent 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. ICC1 in the DC Characteristics
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 VIL, and OE# to VIH.
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.
7
Am29F100
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