HY29LV160 Hynix Semiconductor, HY29LV160 Datasheet - Page 10

• Manufacturer Part Number: HY29LV160
• Description: 16 Mbit (2M x 8/1M x 16) Low Voltage Flash Memory
• Manufacturer: Hynix Semiconductor

HY29LV160
Sector Protect Operation
The hardware sector protection feature disables
both program and erase operations in any sector
or combination of sectors. This function can be
implemented either in-system or by using program-
ming equipment.
The method intended for programming equipment
requires a high voltage (V
and the control pins. Refer to the Appendix at the
end of this document for additional information.
The in-system method requires V
RESET# pin and uses standard microprocessor
bus cycle timing to implement sector protection.
The flow chart in Figure 1 illustrates the algorithm.
The HY29LV160 is shipped with all sectors un-
protected. It is possible to determine whether a
sector is protected or unprotected. See the Elec-
tronic ID Mode section for details.
Sector Unprotect Operation
The hardware sector unprotection feature re-en-
ables both program and erase operations in pre-
viously protected sectors. This function can be
implemented either in-system or by using program-
ming equipment. Note that to unprotect any sec-
10
A[19:12] = Sector to Protect
A[6] = 0, A[1] = 1, A[0] = 0
Write 0x60 to Address
Write 0x60 to device
R E S E T # = V
TRYCNT = 1
Set Address:
Wait 1 us
S T A R T
ID
ID
) on address pin A[9]
Figure 1. Sector Protect Algorithm
ID
Write 0x40 to Address
Read from Address
only on the
Protect Another
Data = 0x01?
Wait 150 us
Sector?
Y E S
Y E S
N O
N O
tor, all unprotected sectors must first be protected
prior to the first sector unprotect write cycle. Also,
the unprotect procedure will cause all sectors to
become unprotected, thus, sectors that require
protection must be protected again after the un-
protect procedure is run.
The method intended for programming equipment
requires a high voltage (V
and the control pins. Refer to the Appendix for
additional information.
The in-system method requires V
RESET# pin and uses standard microprocessor
bus cycle timing to implement sector unprotection.
The flow chart in Figure 2 illustrates the algorithm.
Temporary Sector Unprotect Operation
This feature allows temporary unprotection of pre-
viously protected sectors to allow changing the
data in-system. Sector Unprotect mode is activated
by setting the RESET# pin to V
mode, formerly protected sectors can be pro-
grammed or erased by invoking the appropriate
commands (see Device Commands section).
Once V
ously protected sectors are protected again. Fig-
ure 3 illustrates the algorithm.
Increment TRYCNT
T R Y C N T = 2 5 ?
ID
is removed from RESET#, all the previ-
N O
Y E S
ID
) on address pin A[9]
W r i t e R e s e t C o m m a n d
SECTOR PROTECT
DEVICE FAILURE
ID
R E S E T # = V
C O M P L E T E
. While in this
ID
Rev. 1.2/May 01
only on the
IH