HY29F400
Table 2. HY29F400 Normal Bus Operations
1
Operation
CE#
OE#
L
H
H
X
X
X
X
WE#
H
L
H
X
X
X
X
RESET #
H
H
H
H
V
CC
± 0.5V
L
V
SS
± 0.5V
Address
A
IN
A
IN
X
X
X
X
X
2
DQ[7:0]
D
OUT
D
IN
High-Z
High-Z
High-Z
High-Z
High-Z
DQ[15:8]
3
BYTE# = H BYTE# = L
D
OUT
D
IN
High-Z
High-Z
High-Z
High-Z
High-Z
High-Z
High-Z
High-Z
High-Z
High-Z
High-Z
High-Z
Read
L
Write
L
Output Disable
L
CE# TTL Standby
H
CE# CMOS Standby V
CC
± 0.5V
Hardware Reset
(TTL Standby)
Hardware Reset
(CMOS Standby)
X
X
Notes:
1. L = V
IL
, H = V
IH
, X = Don’t Care, D
OUT
= Data Out, D
IN
= Data In. See DC Characteristics for voltage levels.
2. Address is A[17:-1] in Byte Mode and A[17:0] in Word Mode.
3. DQ[15] is the A[-1] input in Byte Mode (BYTE# = L).
the inputs and control levels they require, and the
resulting outputs. Certain bus operations require
a high voltage on one or more device pins. Those
are described in Table 3.
Read Operation
Data is read from the HY29F400 by using stan-
dard microprocessor read cycles while placing the
address of the byte or word to be read on the
device’s address inputs, A[17:0] in Word mode
(BYTE# = H) or A[17:-1] in Byte mode (BYTE# =
L) . As shown in Table 2, the host system must
drive the CE# and OE# inputs Low and drive WE#
High for a valid read operation to take place. The
device outputs the specified array data on DQ[7:0]
in Byte mode and on DQ[15:0] in Word mode.
Note that DQ[15] serves as address input A[-1]
when the device is operating in Byte mode.
The HY29F400 is automatically set for reading
array data after device power-up and after a hard-
ware reset to ensure that no spurious alteration of
the memory content occurs during the power tran-
sition. No command is necessary in this mode to
obtain array data, and the device remains enabled
for read accesses until the command register con-
tents are altered.
This device features an Erase Suspend mode.
While in this mode, the host may read the array
data from any sector of memory that is not marked
for erasure. If the host attempts to read from an
address within an erase-suspended sector, or
while the device is performing an erase or byte/
6
word program operation, the device outputs sta-
tus data instead of array data. After completing a
programming operation in the Erase Suspend
mode, the system may once again read array data
with the same exceptions noted above. After com-
pleting an internal program or internal erase algo-
rithm, the HY29F400 automatically returns to the
Read Array Data mode.
The host must issue a hardware reset or the soft-
ware reset command (see Command Definitions)
to return a sector to the read array data mode if
DQ[5] goes high during a program or erase cycle,
or to return the device to the Read Array Data
mode while it is in the Electronic ID mode.
Write Operation
Certain operations, including programming data
and erasing sectors of memory, require the host
to write a command or command sequence to the
HY29F400. Writes to the device are performed
by placing the byte or word address on the device’s
address inputs while the data to be written is input
on DQ[7:0] in Byte mode (BYTE# = L) and on
DQ[15:0] in Word mode (BYTE# = H). The host
system must drive the CE# and WE# pins Low
and drive OE# High for a valid write operation to
take place. All addresses are latched on the fall-
ing edge of WE# or CE#, whichever happens later.
All data is latched on the rising edge of WE# or
CE#, whichever happens first.
Rev. 5.2/May 01
HYNIX [ HYNIX SEMICONDUCTOR ]
