HY29F002T Datasheet, PDF (7/38 Pages) Hynix Semiconductor – 2 Megabit (256K x 8), 5 Volt-only, Flash Memory

set operation is completed within a time of t_RP. In
this case, the host can perform a read or write
operation t_RH after the RESET# pin returns High.
The RESET# pin may be tied to the system reset
signal. Thus, a system reset would also reset the
device, enabling the system to read the boot-up
firmware from the Flash memory.
Sector Protect/Unprotect Operations
Hardware sector protection can be invoked to dis-
able program and erase operations in any single
sector or combination of sectors. This function is
typically used to protect data in the device from
unauthorized or accidental attempts to program
or erase the device while it is in the system (e.g.,
by a virus) and is implemented using program-
ming equipment. Sector unprotection re-enables
the program and erase operations in previously
protected sectors.
Table 1 identifies the seven sector in the top and
bottom boot block versions of the HY29F002T and
the address ranges that each covers. The device
is shipped with all sectors unprotected.
The sector protect/unprotect operations require a
high voltage (V_ID) on address pin A[9] and the CE#
and/or OE# control pins, as detailed in Table 3.
When implementing these operations, note that
V_CC must be applied to the device before applying
V_ID, and that V_ID should be removed before remov-
ing V_CC from the device.
The flow chart in Figure 1 illustrates the proce-
dure for protecting sectors, and timing specifica-
tions and waveforms are shown in the specifica-
tions section of this document. Verification of pro-
tection is accomplished as described in the Elec-
tronic ID Mode section and shown in the flow chart.
The procedure for sector unprotection is illustrated
in the flow chart in Figure 2, and timing specifica-
tions and waveforms are given at the end of this
document. Note that to unprotect any sector, all
HY29F002T
unprotected sectors must first be protected prior
to the first unprotect write cycle.
Sectors can also be temporarily unprotected as
described in the next section.
Temporary Sector Unprotect Operation
This feature allows temporary unprotection of pre-
viously protected sectors to allow changing the
data in-system. Temporary Sector Unprotect
mode is activated by setting the RESET# pin to
V_ID. While in this mode, formerly protected sec-
tors can be programmed or erased by invoking
the appropriate commands (see Device Com-
mands section). Once V_ID is removed from RE-
SET#, all the previously protected sectors are pro-
tected again. Figure 3 illustrates the algorithm.
Electronic ID Mode Operation
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. The Electronic ID information can also
be obtained by the host through a command se-
quence, as described in the Device Commands
section.
Operation in the Electronic ID mode requires V_ID
on address pin A[9], with additional requirements
for obtaining specific data items as listed in Table
2:
n A read cycle at address 0xXXX00 retrieves the
manufacturer code (Hynix = 0xAD).
n A read cycle at address 0xXXX01 returns the
device code (HY29F002T = 0xB0).
n A read cycle containing a sector address (Table
1) 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.
Rev. 4.1/May 01
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