P R E L I M I N A R Y
START
START
Protect all sectors:
The indicated portion
of the sector protect
algorithm must be
performed for all
PLSCNT = 1
PLSCNT = 1
RESET# = VID
RESET# = VID
unprotected sectors
prior to issuing the
first sector
Wait 1 µs
Wait 1 µs
unprotect address
No
First Write
No
First Write
Cycle = 60h?
Temporary Sector
Unprotect Mode
Temporary Sector
Unprotect Mode
Cycle = 60h?
Yes
Yes
Set up sector
address
No
All sectors
protected?
Sector Protect:
Write 60h to sector
address with
A6 = 0, A1 = 1,
A0 = 0
Yes
Set up first sector
address
Sector Unprotect:
Wait 150 µs
Write 60h to sector
address with
A6 = 1, A1 = 1,
A0 = 0
Verify Sector
Protect: Write 40h
to sector address
with A6 = 0,
Reset
PLSCNT = 1
Increment
PLSCNT
Wait 15 ms
A1 = 1, A0 = 0
Verify Sector
Unprotect: Write
40h to sector
address with
A6 = 1, A1 = 1,
A0 = 0
Read from
sector address
with A6 = 0,
A1 = 1, A0 = 0
Increment
PLSCNT
No
No
PLSCNT
= 25?
Read from
sector address
with A6 = 1,
Data = 01h?
Yes
A1 = 1, A0 = 0
No
Yes
Set up
next sector
address
Yes
No
PLSCNT
= 1000?
Protect another
sector?
Data = 00h?
Yes
Device failed
No
Yes
Remove VID
from RESET#
No
Last sector
verified?
Device failed
Write reset
command
Yes
Remove VID
Sector Unprotect
Algorithm
from RESET#
Sector Protect
Algorithm
Sector Protect
complete
Write reset
command
Sector Unprotect
complete
Note: The term “sector” in the figure applies to both sectors and sector blocks.
Figure 2. In-System Sector/Sector Block Protect and Unprotect Algorithms
July 19, 2002
Am49DL32xBG
21
CYPRESS [ CYPRESS ]
