HY29F400
After an erase-suspended program operation is
complete, the host can initiate another program-
ming operation (or read operation) within non-sus-
pended sectors. The host can determine the sta-
tus of a program operation during the erase-sus-
pended state just as in the standard programming
operation.
mode, but is invalid while the device is actively
programming or erasing.
The Electronic ID command sequence is initiated
by writing two unlock cycles, followed by the Elec-
tronic ID command. The device then enters the
Electronic ID mode, and:
n A read cycle at address 0xXXX00 retrieves the
The system must write the Erase Resume com-
mand to exit the Erase Suspend mode and con-
tinue the sector erase operation. Further writes of
the Resume command are ignored. Another Erase
Suspend command can be written after the de-
vice has resumed erasing.
manufacturer code (Hynix = 0xAD).
n In Word mode, a read cycle at address
0xXXX01 returns the device code (HY29F400T
= 0x2223, HY29F400B = 0x22AB). In Byte
mode, the same information is retrieved from
address 0xXXX02 (HY29F400T = 0x23,
HY29F400B = 0xAB).
The host may also write the Electronic ID com-
mand sequence when the device is in the Erase
Suspend mode. The device allows reading Elec-
tronic ID codes even if the addresses used for the
ID read cycles are within erasing sectors, since
the codes are not stored in the memory array.
When the device exits the Electronic ID mode, the
device reverts to the Erase Suspend mode, and
is ready for another valid operation. See Electronic
ID section for more information.
n In Word mode, a read cycle containing a sec-
tor address in A[17:12] and the address 0x02
in A[7:0] returns 0xXX01 if that sector is pro-
tected, or 0xXX00 if it is unprotected. In Byte
mode, the status information is retrieved using
0x04 in A[6:-1] (0x01 if the sector is protected,
0x00 if the sector is unprotected).
The host system may read at any address any
number of times, without initiating another com-
mand sequence. Thus, for example, the host may
determine the protection status for all sectors by
doing successive reads at the address specified
above while changing the sector address for each
cycle.
Electronic ID Command
The Electronic ID operation intended for use in
programming equipment has been described pre-
viously. The host processor can also be obtain
the same data by using the Electronic ID com-
mand sequence shown in Table 5. This method
does not require VID on any pin. The Electronic ID
command sequence may be invoked while the
device is in the Read mode or the Erase Suspend
The system must write the Reset command to exit
the Electronic ID mode and return to the Read
mode, or to the Erase Suspend mode if the de-
vice was in that mode when the command se-
quence was issued.
WRITE OPERATION STATUS
The HY29F400 provides a number of facilities to
determine the status of a program or erase op-
eration. These are the RY/BY# (Ready/Busy#)
pin and certain bits of a status word which can be
read from the device during the programming and
erase operations. Table 6 summarizes the status
indications and further detail is provided in the
subsections which follow.
BY# is valid after the rising edge of the final WE#
pulse in the corresponding command sequence.
If the output is Low (busy), the device is actively
erasing or programming, including programming
while in the Erase Suspend mode. If the output is
High (ready), the device has completed the op-
eration and is ready to read array data in the nor-
mal or Erase Suspend modes, or it is in the standby
mode.
RY/BY# - Ready/Busy#
RY/BY# is an open-drain output pin that indicates
whether a programming or erase Automatic Algo-
rithm is in progress or has completed. A pull-up
resistor to VCC is required for proper operation. RY/
DQ[7] - Data# Polling
The Data# (“Data Bar”) Polling bit, DQ[7], indicates
to the host system whether an Automatic Algo-
Rev. 5.2/May 01
15
HYNIX [ HYNIX SEMICONDUCTOR ]
