HY29LV400 Datasheet, PDF (16/40 Pages) Hynix Semiconductor – 4 Mbit (512K x 8/256K x 16) Low Voltage Flash Memory

HY29LV400
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 specified 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 command se-
quence, and is ignored if it is issued during chip
erase or programming operations.
The HY29LV400 requires a maximum of 20 µs to
suspend the erase operation if the Erase Suspend
command is issued during sector erasure. How-
ever, if the command is written during the time-
out, the time-out is terminated and the erase op-
eration is suspended immediately. Once the erase
operation has been suspended, the system can
read array data from or program data to any sec-
tor not specified for erasure. Normal read and
write timings and command definitions 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 the Write Operation Status sec-
tion 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 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 at addresses within erasing
sectors, since the codes are not stored in the
memory array. When the device exits the Elec-
tronic ID mode, the device reverts to the Erase
Suspend mode, and is ready for another valid op-
eration. See Electronic ID Mode section for more
information.
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.
Electronic ID Command
The Electronic ID mode provides manufacturer and
device identification and sector protection verifi-
cation through identifier codes output on DQ[7:0].
This mode is intended primarily for programming
equipment to automatically match a device to be
programmed with its corresponding programming
algorithm.
Two methods are provided for accessing the Elec-
tronic ID data. The first requires V_ID on address
pin A[9], as described previously in the Device
Operations section.
The Electronic ID data can also be obtained by
the host by invoking the Electronic ID command,
as shown in Table 6. This method does not re-
quire V_ID. The Electronic ID command sequence
may be issued while the device is in the Read
mode or in the Erase Suspend Read mode, that
is, except while 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 the system may read at
any address any number of times, without initiat-
ing another command sequence.
n A read cycle at address 0xXXX00 retrieves the
manufacturer code.
n A read cycle at address 0xXXX01 in Word
mode or 0xXXX02 in Byte mode returns the
device code.
n A read cycle containing a sector address (SA)
in A[17:12] and the address 0x02 in A[7:0] in
Word mode (or 0x04 in A[6:0, -1] in Byte mode)
returns 0x01 if that sector is protected, or 0x00
if it is unprotected.
The system must write the Reset command to exit
the Electronic ID mode and return to reading ar-
ray data.
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Rev. 1.0/Nov. 01