AM29SL400DB90 SPANSION [SPANSION], AM29SL400DB90 Datasheet - Page 14

• Manufacturer Part Number: AM29SL400DB90
• Description: 4 Megabit (512 K x 8-Bit/256 K x 16-Bit) CMOS 1.8 Volt-only Super Low Voltage Flash Memory
• Manufacturer: SPANSION [SPANSION]

12
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
A6 = 0, A1 = 1,
Protect another
Sector Protect:
sector address
Figure 1. In-system Sector Protection/Unprotection Algorithms
RESET# = V
A1 = 1, A0 = 0
A1 = 1, A0 = 0
Sector Protect
from RESET#
Verify Sector
Set up sector
PLSCNT = 1
Cycle = 60h?
Remove V
address with
with A6 = 0,
with A6 = 0,
Data = 01h?
Wait 150 µs
Write reset
Read from
First Write
command
Wait 1 µs
complete
address
START
sector?
A0 = 0
Yes
Yes
No
ID
A D V A N C E
ID
Yes
PLSCNT = 1
Reset
Am29SL400D
I N F O R M A T I O N
The indicated portion
Protect all sectors:
unprotected sectors
of the sector protect
prior to issuing the
unprotect address
algorithm must be
performed for all
Sector Unprotect
first sector
Algorithm
Device failed
Increment
PLSCNT
PLSCNT
= 1000?
Yes
No
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
from RESET#
Verify Sector
40h to sector
address with
Cycle = 60h?
Remove V
PLSCNT = 1
address with
with A6 = 1,
Data = 00h?
Wait 15 ms
Write reset
Read from
First Write
Last sector
command
Wait 1 µs
All sectors
protected?
complete
address
verified?
START
A0 = 0
A0 = 0
Rev. A Amend. +1 April 13, 2005
Yes
Yes
Yes
Yes
ID
ID
No
No
Temporary Sector
Unprotect Mode
next sector
address
Set up