MT28C3224P20 Micron Technology, MT28C3224P20 Datasheet - Page 22

• Manufacturer Part Number: MT28C3224P20
• Description: FLASH AND SRAM COMBO MEMORY
• Manufacturer: Micron Technology

2 Meg x 16 Page Flash 256K x 16 SRAM Combo Memory
MT28C3224P20_3.p65 – Rev. 3, Pub. 7/02
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 9).
F_WP#
The LOCK DOWN function is dependent on the
0
0
0
1
1
1
1
DQ1
0
0
1
0
0
1
1
NOTE: 1. Other locations within the configuration address space are reserved by
ITEM
Manufacturer Code (x16)
Device Code
·
·
Block Lock Configuration
·
·
·
Chip Protection Register Lock
Chip Protection Register 1
Chip Protection Register 2
DQ0
0
1
1
0
1
0
1
Top boot configuration
Bottom boot configuration
Block is unlocked
Block is locked
Block is locked down
2. “XX” specifies the block address of lock configuration.
Micron for future use.
Locked (Default)
Lock Down
Lock Down
Lock Down
Unlocked
Unlocked
Disabled
Disabled
NAME
Locked
Chip Configuration Addressing
Block Locking State Transition
ERASE/PROGRAM
Table 8
Table 9
ALLOWED
22
256K x 16 SRAM COMBO MEMORY
ADDRESS
00000h
00001h
XX002h
80h
81h–84h
85h–88h
Yes
Yes
Yes
No
No
No
No
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 +00002 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 8 shows the block locking
state transition scheme. After data is read from the
The lock status of every block can be read in the
2
Micron Technology, Inc., reserves the right to change products or specifications without notice.
2 MEG x 16 PAGE FLASH
To [001]
To [101]
To [111]
LOCK
DATA
002Ch
44B4h
44B5h
Lock
DQ0 = 0
DQ0 = 1
DQ1 = 1
PR Lock
Factory Data
User Data
–
–
–
–
1
UNLOCK
To [000]
To [100]
To [110]
–
–
–
–
©2002, Micron Technology, Inc.
ADVANCE
To [011]
To [011]
To [111]
To [111]
To [111]
DOWN
LOCK
–
–