s71jl064ha0bfw62 Advanced Micro Devices, s71jl064ha0bfw62 Datasheet - Page 55

• Manufacturer Part Number: s71jl064ha0bfw62
• Description: Stacked Multi-chip Product Mcp Flash Memory And Psram Cmos 3.0volt-only, Simultaneous Operation Flash Memories And Static Ram/pseudo-static Ram
• Manufacturer: Advanced Micro Devices

February 25, 2004 S71JLxxxHxx_00A1
Hardware Data Protection
Once the SecSi Sector is locked and verified, the system must write the Exit SecSi
Sector Region command sequence to return to reading and writing the remainder
of the array.
The SecSi Sector lock must be used with caution since, once locked, there is no
procedure available for unlocking the SecSi Sector area and none of the bits in
the SecSi Sector memory space can be modified in any way.
The command sequence requirement of unlock cycles for programming or erasing
provides data protection against inadvertent writes (refer to
mand definitions). In addition, the following hardware data protection measures
prevent accidental erasure or programming, which might otherwise be caused by
spurious system level signals during V
or from system noise.
Low V
When V
tects data during V
internal program/erase circuits are disabled, and the device resets to the read
mode. Subsequent writes are ignored until V
must provide the proper signals to the control pins to prevent unintentional writes
when V
Write Pulse “Glitch” Protection
Noise pulses of less than 5 ns (typical) on OE#, CE# or WE# do not initiate a write
cycle.
tion of the SecSi Sector Region without raising any device pin to a high
voltage. Note that this method is only applicable to the SecSi Sector.
To verify the protect/unprotect status of the SecSi Sector, follow the algo-
rithm shown in
CC
CC
CC
is less than V
is greater than V
Write Inhibit
Figure
CC
P r e l i m i n a r y
Figure 3. SecSi Sector Protect Verify
power-up and power-down. The command register and all
Write 40h to SecSi
LKO
Read from SecSi
Sector address
A1 = 1, A0 = 0
A1 = 1, A0 = 0
Sector address
Write 60h to
with A6 = 0,
with A6 = 0,
any address
3.
, the device does not accept any write cycles. This pro-
RESET# =
Wait 1 ms
V
LKO
IH
START
or V
.
ID
S29JL064H
CC
power-up and power-down transitions,
Remove V
If data = 00h,
SecSi Sector is
If data = 01h,
SecSi Sector is
from RESET#
Protect Verify
unprotected.
CC
SecSi Sector
Write reset
protected.
command
complete
is greater than V
IH
or V
ID
Table 11
LKO
. The system
for com-
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