s29as008j Meet Spansion Inc., s29as008j Datasheet - Page 20

• Manufacturer Part Number: s29as008j
• Description: 8 Megabit 1 M X 8-bit/512 K X 16-bit Cmos 1.8 Volt-only Boot Sector Flash Memory
• Manufacturer: Meet Spansion Inc.

20
Sector Protect
Temporary Sector
Unprotect Mode
Algorithm
Device failed
Increment
PLSCNT
PLSCNT
= 25?
No
Yes
No
No
Write 60h to sector
Protect: Write 40h
to sector address
Protect another
Sector Protect:
sector address
RESET# = V
A1 = 1, A0 = 0
A1 = 1, A0 = 0
A1 = 1, A0 = 0
Sector Protect
from RESET#
Verify Sector
Set up sector
address with
A3 = A2 = 0,
A3 = A2 = 0,
A3 = A2 = 0,
PLSCNT = 1
Cycle = 60h?
Remove V
with A6 = 0,
with A6 = 0,
Data = 01h?
Wait 100 µs
Write reset
Read from
First Write
command
Wait 1 µs
complete
address
START
A6 = 0,
sector?
No
Yes
Yes
Figure 7.1 In-System Sector Protect/Unprotect Algorithms
ID
ID
Yes
D a t a
PLSCNT = 1
Reset
S h e e t
S29AS008J
The indicated portion
unprotected sectors
Protect all sectors:
of the sector protect
prior to issuing the
unprotect address
algorithm must be
performed for all
( A d v a n c e
Sector Unprotect
first sector
Algorithm
Device failed
Increment
PLSCNT
PLSCNT
= 1000?
No
Yes
I n f o r m a t i o n )
No
No
Write 60h to sector
Set up first sector
Sector Unprotect:
Unprotect: Write
Sector Unprotect
A6 = 1, A1 = 1,
A6 = 1, A1 = 1,
sector address
RESET# = V
A1 = 1, A0 = 0
40h to sector
A3 = A2 = 0,
from RESET#
Verify Sector
address with
Cycle = 60h?
PLSCNT = 1
address with
with A6 = 1,
Remove V
Data = 00h?
Write reset
Wait 10 ms
Read from
Last sector
First Write
command
All sectors
protected?
Wait 1 µs
complete
address
verified?
START
A0 = 0
A0 = 0
S29AS008J_00_03 June 6, 2008
Yes
Yes
Yes
Yes
ID
ID
No
No
Temporary Sector
Unprotect Mode
next sector
address
Set up