AM29DL400BB-120EC AMD [Advanced Micro Devices], AM29DL400BB-120EC Datasheet - Page 14

• Manufacturer Part Number: AM29DL400BB-120EC
• Description: 4 Megabit (512 K x 8-Bit/256 K x 16-Bit) CMOS 3.0 Volt-only, Simultaneous Operation Flash Memory
• Manufacturer: AMD [Advanced Micro Devices]

14
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,
Sector Protect:
sector address
Protect another
RESET# = V
A1 = 1, A0 = 0
A1 = 1, A0 = 0
Sector Protect
from RESET#
Set up sector
Verify Sector
Cycle = 60h?
PLSCNT = 1
address with
Remove V
with A6 = 0,
with A6 = 0,
Wait 150 µs
Data = 01h?
Write reset
Read from
First Write
command
Wait 1 s
complete
address
Figure 2. In-System Sector Protect/Unprotect Algorithms
START
sector?
A0 = 0
Yes
Yes
No
ID
ID
Yes
PLSCNT = 1
P R E L I M I N A R Y
Reset
Am29DL400B
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
40h to sector
from RESET#
Verify Sector
address with
Cycle = 60h?
PLSCNT = 1
address with
Remove V
with A6 = 1,
Data = 00h?
Write reset
Wait 15 ms
Read from
Last sector
First Write
protected?
command
Wait 1 s
All sectors
complete
verified?
address
START
A0 = 0
A0 = 0
Yes
Yes
Yes
Yes
ID
ID
No
No
Temporary Sector
Unprotect Mode
next sector
address
Set up
21606C-6