MT28C6428P20FM-80 BET Micron Technology Inc, MT28C6428P20FM-80 BET Datasheet - Page 28

• Manufacturer Part Number: MT28C6428P20FM-80 BET
• Manufacturer: Micron Technology Inc

Specifications of MT28C6428P20FM-80 BET

• Operating Temperature (max): 85C
• Mounting: Surface Mount
• Lead Free Status / RoHS Status: Not Compliant

4 Meg x 16 Asynchronous/Page Flash 512K x 16 SRAM Combo Memory
MT28C6428P20_4.p65 – Rev. 4, Pub. 10/02
LOCKED DOWN STATE
PROGRAM and ERASE operations, but their protection
status cannot be changed using software commands
alone. A locked or unlocked block can be locked down
by writing the lock down command sequence, 60h fol-
lowed by 2Fh. Locked down blocks revert to the locked
state when the device is reset or powered down.
F_WP# input. When F_WP# = 0, blocks in lock down
[011] are protected from program, erase, and lock sta-
tus changes. When F_WP# = 1, the LOCK DOWN func-
tion is disabled ([111]) and locked down blocks can be
individually unlocked by a software command to the
[110] state, where they can be erased and programmed.
These blocks can then be relocked [111] and unlocked
[110], as desired, as long as F_WP# remains HIGH.
When F_WP# goes LOW, blocks that were previously
locked down return to the lock down state [011] regard-
less of any changes made while F_WP# was HIGH. De-
vice reset or power-down resets all locks, including
those in lock down, to the locked state (see Table 10).
READING A BLOCK’S LOCK STATUS
read device identification mode. To enter this mode,
write 90h to the bank containing address 00h. Subse-
quent READs at block address +00002h will output the
lock status of that block. The lowest two outputs, DQ0
and DQ1, represent the lock status. DQ0 indicates the
block lock/unlock status and is set by the LOCK com-
mand and cleared by the UNLOCK command. It is also
automatically set when entering lock down. DQ1 indi-
cates lock down status and is set by the LOCK DOWN
command. It can only be cleared by reset or power-
down, not by software. Table 9 shows the block locking
state transition scheme. The READ ARRAY command,
F_WP#
Blocks locked down (state [011]) are protected from
The LOCK DOWN function is dependent on the
The lock status of every block can be read in the
0
0
0
1
1
1
1
DQ1
0
0
1
0
0
1
1
DQ0
0
1
1
0
1
0
1
Locked (Default)
Lock Down
Lock Down
Lock Down
Unlocked
Unlocked
Disabled
Disabled
NAME
Locked
Block Locking State Transition
4 MEG x 16 ASYNCHRONOUS/PAGE FLASH
ERASE/PROGRAM
Table 9
ALLOWED
28
512K x 16 SRAM COMBO MEMORY
Yes
Yes
Yes
No
No
No
No
FFh, must be issued to the bank containing address
00h prior to issuing other commands.
LOCKING OPERATIONS DURING ERASE
SUSPEND
ing an ERASE SUSPEND by using the standard locking
command sequences to unlock, lock, or lock down. This
is useful in the case when another block needs to be
updated while an ERASE operation is in progress.
tion, first write the ERASE SUSPEND command (B0h),
then check the status register until it indicates that the
ERASE operation has been suspended. Next, write the
desired lock command sequence to block lock, and the
lock status will be changed. After completing any de-
sired LOCK, READ, or PROGRAM operations, resume
the ERASE operation with the ERASE RESUME com-
mand (D0h).
SUSPEND on the same block, the locking status bits
are changed immediately. When the ERASE is resumed,
the ERASE operation completes.
PROGRAM SUSPEND.
STATUS REGISTER ERROR CHECKING
quences during ERASE SUSPEND can introduce ambi-
guity into status register results.
invalid command produces a lock command error (SR4
and SR5 are set to “1”) in the status register. If a lock
command error occurs during an ERASE SUSPEND,
SR4 and SR5 are set to “1” and remain at “1” after the
ERASE SUSPEND command is issued. When the ERASE
Changes to block lock status can be performed dur-
To change block locking during an ERASE opera-
If a block is locked or locked down during an ERASE
A locking operation cannot be performed during a
Using nested locking or program command se-
Following protection configuration setup (60h), an
Micron Technology, Inc., reserves the right to change products or specifications without notice.
To [001]
To [101]
To [111]
LOCK
–
–
–
–
UNLOCK
To [000]
To [100]
To [110]
–
–
–
–
©2002, Micron Technology, Inc.
To [011]
To [011]
To [111]
To [111]
To [111]
DOWN
LOCK
–
–