HY29F400 Hynix Semiconductor, HY29F400 Datasheet - Page 14

• Manufacturer Part Number: HY29F400
• Description: 4 Megabit (512Kx8/256Kx16) 5 Volt-only Flash Memory
• Manufacturer: Hynix Semiconductor

additional sector erase data cycles. Once the sec-
tor erase operation itself has begun, only the Erase
Suspend command is valid. All other commands
are ignored.
As for the Chip Erase command, note that a hard-
ware reset immediately terminates the erase op-
eration. To ensure data integrity, the aborted Sec-
tor Erase command sequence should be reissued
once the reset operation is complete.
When the Automatic Erase algorithm terminates,
the device returns to the Read mode. Several
methods are provided to allow the host to deter-
mine the status of the erase operation, as de-
scribed in the Write Operation Status section.
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 to, 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
HY29F400
14
Address for Erase Operation
Setup First (or Next) Sector
Write Last Cycle (SA/0x30)
Write First Five Cycles of
Command Sequence
Command Sequence
of SECTOR ERASE
Additional Sector?
SECTOR ERASE
Erase An
START
N O
YES
Time-out (DQ[3])
Sector Erase
Expired?
Figure 6. Sector Erase Procedure
N O
YES
sequence and any subsequent sector erase data
cycles, and is ignored if it is issued during chip
erase or programming operations.
The HY29F400 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.
(See Write Operation Status
ERASE COMPLETE
Check Erase Status
this erase cycle must be erased
but which were not specified in
Sectors which require erasure
Section)
later using a new command
Normal Exit
sequence
DQ[5] Error Exit
ERROR RECOVERY
GO TO
Rev. 5.2/May 01