COTS PEM
BOOT SECTOR FLASH
Austin Semiconductor, Inc.
AS29LV016J
Figure 2. In-System Sector Protect/Unprotect Algorithms
START
PLSCNT = 1
RESET# = VID
Wait 1 μs
Temporary Sector
No First Write
Group Unprotect Mode
Cycle = 60h?
Protect all sectors:
The indicated portion
of the sector group protect
algorithm must be
performed for all
unprotected sector groups
prior to issuing the
first sector group
unprotect address
START
PLSCNT = 1
RESET# = VID
Wait 1 μs
First Write No
Cycle = 60h?
Temporary Sector
Group Unprotect Mode
Yes
Increment
PLSCNT
No
PLSCNT
= 25?
Yes
Device failed
Yes
Set up sector
group address
Sector Group Protect:
Write 60h to sector group
address with
A6 = 0,
A3 = A2 = 0,
A1 = 1, A0 = 0
Wait 150 μs
Verify Sector Group
Protect: Write 40h
to sector group address
with A6 = 0,
A3 = A2 = 0,
A1 = 1, A0 = 0
Read from
sector group address
with A6 = 0,
A3 = A2 = 0,
A1 = 1, A0 = 0
Reset
PLSCNT = 1
No
Data = 01h?
Yes
Yes
Protect another
sector group?
Increment
PLSCNT
No
PLSCNT
= 1000?
Yes
No All sectors
protected?
Yes
Set up first sector
group address
Sector Group Unprotect:
Write 60h to sector
address with
A6 = 1,
A3 = A2 = 0,
A1 = 1, A0 = 0
Wait 1.5 ms
Verify Sector Group
Unprotect: Write
40h to sector group
address with
A6 = 1,
A3 = A2 = 0,
A1 = 1, A0 = 0
Read from
sector group address
with A6 = 1,
A3 = A2 = 0,
A1 = 1, A0 = 0
No
Data = 00h?
Set up
next sector group
address
Yes
No
Remove VID
from RESET#
Write reset
command
Sector Group
Sector Group
Protect Algorithm Protect complete
Device failed
Last sector No
group verified?
Yes
Sector Group
Unprotect Algorithm
Remove VID
from RESET#
Write reset
command
Sector Group
Unprotect complete
AS29LV016J
Rev. 0.0 02/09
13
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