HY29F002T Datasheet, PDF (14/38 Pages) Hynix Semiconductor – 2 Megabit (256K x 8), 5 Volt-only, Flash Memory

HY29F002T
Figure 6 illustrates the Sector Erase procedure.
Erase Suspend/Erase Resume Commands
The Erase Suspend command allows the system
to interrupt a sector erase operation to read data
from, or program data in, any sector not being
erased. The command causes the erase opera-
tion to be suspended in all sectors selected for
erasure. This command is valid only during the
sector erase operation, including during the 50 µs
time-out period at the end of the initial command
sequence and any subsequent sector erase data
cycles, and is ignored if it is issued during chip
erase or programming operations.
The HY29F002T requires a maximum of 20 µs to
suspend the erase operation if the Erase Suspend
command is issued during active sector erasure.
However, if the command is written during the time-
out, the time-out is terminated and the erase op-
eration is suspended immediately. Any subse-
quent attempts to specify additional sectors for
erasure by writing the sector erase data cycle (SA/
0x30) will be interpreted as the Erase Resume
command (XXX/0x30), which will cause the Auto-
matic Erase algorithm to begin its operation. Note
that any other command during the time-out will
reset the device to the Read mode.
Once the erase operation has been suspended,
the system can read array data from or program
data to any sector not selected for erasure. Nor-
mal read and write timings and command defini-
tions apply. Reading at any address within erase-
suspended sectors produces status data on
DQ[7:0]. The host can use DQ[7], or DQ[6] and
DQ[2] together, to determine if a sector is actively
erasing or is erase-suspended. See “Write Op-
eration Status” for information on these status bits.
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.
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.
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.
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 V_ID on any pin. The Electronic ID
command sequence may be invoked while the
device is in the Read mode or the Erase Suspend
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
manufacturer code (Hynix = 0xAD).
n A read cycle at address 0xXXX01 returns the
device code (0xB0).
n A read cycle containing a sector address in
A[17:13] and the address 0x02 in A[7:0] returns
0x01 if that sector is protected, or 0x00 if it 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 address 0x02 while
changing the sector address in A[17:13] for each
cycle.
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.
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Rev. 4.1/May 01